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An J, Yang H, Park SM, Chwae YJ, Joe EH. The LRRK2-G2019S mutation attenuates repair of brain injury partially by reducing the release of osteopontin-containing monocytic exosome-like vesicles. Neurobiol Dis 2024; 197:106528. [PMID: 38740348 DOI: 10.1016/j.nbd.2024.106528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/22/2024] [Accepted: 05/09/2024] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND Brain injury has been suggested as a risk factor for neurodegenerative diseases. Accordingly, defects in the brain's intrinsic capacity to repair injury may result in the accumulation of damage and a progressive loss of brain function. The G2019S (GS) mutation in LRRK2 (leucine rich repeat kinase 2) is the most prevalent genetic alteration in Parkinson's disease (PD). Here, we sought to investigate how this LRRK2-GS mutation affects repair of the injured brain. METHODS Brain injury was induced by stereotaxic injection of ATP, a damage-associated molecular pattern (DAMP) component, into the striatum of wild-type (WT) and LRRK2-GS mice. Effects of the LRRK2-GS mutation on brain injury and the recovery from injury were examined by analyzing the molecular and cellular behavior of neurons, astrocytes, and monocytes. RESULTS Damaged neurons express osteopontin (OPN), a factor associated with brain repair. Following ATP-induced damage, monocytes entered injured brains, phagocytosing damaged neurons and producing exosome-like vesicles (EVs) containing OPN through activation of the inflammasome and subsequent pyroptosis. Following EV production, neurons and astrocytes processes elongated towards injured cores. In LRRK2-GS mice, OPN expression and monocytic pyroptosis were decreased compared with that in WT mice, resulting in diminished release of OPN-containing EVs and attenuated elongation of neuron and astrocyte processes. In addition, exosomes prepared from injured LRRK2-GS brains induced neurite outgrowth less efficiently than those from injured WT brains. CONCLUSIONS The LRRK2-GS mutation delays repair of injured brains through reduced expression of OPN and diminished release of OPN-containing EVs from monocytes. These findings suggest that the LRRK2-GS mutation may promote the development of PD by delaying the repair of brain injury.
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Affiliation(s)
- Jiawei An
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea; Department of Pharmacology, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea; Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea
| | - Haijie Yang
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea; Department of Pharmacology, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea; Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea
| | - Sang Myun Park
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea; Department of Pharmacology, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea; Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea
| | - Yong-Joon Chwae
- Department of Microbiology, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea
| | - Eun-Hye Joe
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea; Department of Pharmacology, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea; Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Kyunggi-do 16499, Republic of Korea.
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Schädlich IS, Winzer R, Stabernack J, Tolosa E, Magnus T, Rissiek B. The role of the ATP-adenosine axis in ischemic stroke. Semin Immunopathol 2023:10.1007/s00281-023-00987-3. [PMID: 36917241 DOI: 10.1007/s00281-023-00987-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 01/25/2023] [Indexed: 03/16/2023]
Abstract
In ischemic stroke, the primary neuronal injury caused by the disruption of energy supply is further exacerbated by secondary sterile inflammation. The inflammatory cascade is largely initiated by the purine adenosine triphosphate (ATP) which is extensively released to the interstitial space during brain ischemia and functions as an extracellular danger signaling molecule. By engaging P2 receptors, extracellular ATP activates microglia leading to cytokine and chemokine production and subsequent immune cell recruitment from the periphery which further amplifies post-stroke inflammation. The ectonucleotidases CD39 and CD73 shape and balance the inflammatory environment by stepwise degrading extracellular ATP to adenosine which itself has neuroprotective and anti-inflammatory signaling properties. The neuroprotective effects of adenosine are mainly mediated through A1 receptors and inhibition of glutamatergic excitotoxicity, while the anti-inflammatory capacities of adenosine have been primarily attributed to A2A receptor activation on infiltrating immune cells in the subacute phase after stroke. In this review, we summarize the current state of knowledge on the ATP-adenosine axis in ischemic stroke, discuss contradictory results, and point out potential pitfalls towards translating therapeutic approaches from rodent stroke models to human patients.
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Affiliation(s)
- Ines Sophie Schädlich
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Riekje Winzer
- Institute of Immunology, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Joschi Stabernack
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Eva Tolosa
- Institute of Immunology, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
| | - Tim Magnus
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany.
| | - Björn Rissiek
- Department of Neurology, University Medical Centre Hamburg-Eppendorf, Martinistraße 52, 20246, Hamburg, Germany
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3
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Huang Y, Omorou M, Gao M, Mu C, Xu W, Xu H. Hydrogen sulfide and its donors for the treatment of cerebral ischaemia-reperfusion injury: A comprehensive review. Biomed Pharmacother 2023; 161:114506. [PMID: 36906977 DOI: 10.1016/j.biopha.2023.114506] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/06/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
As an endogenous gas signalling molecule, hydrogen sulfide (H2S) is frequently present in a variety of mammals and plays a significant role in the cardiovascular and nervous systems. Reactive oxygen species (ROS) are produced in large quantities as a result of cerebral ischaemia-reperfusion, which is a very serious class of cerebrovascular diseases. ROS cause oxidative stress and induce specific gene expression that results in apoptosis. H2S reduces cerebral ischaemia-reperfusion-induced secondary injury via anti-oxidative stress injury, suppression of the inflammatory response, inhibition of apoptosis, attenuation of cerebrovascular endothelial cell injury, modulation of autophagy, and antagonism of P2X7 receptors, and it plays an important biological role in other cerebral ischaemic injury events. Despite the many limitations of the hydrogen sulfide therapy delivery strategy and the difficulty in controlling the ideal concentration, relevant experimental evidence demonstrating that H2S plays an excellent neuroprotective role in cerebral ischaemia-reperfusion injury (CIRI). This paper examines the synthesis and metabolism of the gas molecule H2S in the brain as well as the molecular mechanisms of H2S donors in cerebral ischaemia-reperfusion injury and possibly other unknown biological functions. With the active development in this field, it is expected that this review will assist researchers in their search for the potential value of hydrogen sulfide and provide new ideas for preclinical trials of exogenous H2S.
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Affiliation(s)
- Yiwei Huang
- Basic Medical College, Jiamusi University, Jiamusi 154007, Heilongjiang, China; Key Laboratory of Microecology-Immune Regulatory Network and Related Diseases, Jiamusi 154007, Heilongjiang, China.
| | - Moussa Omorou
- Key Laboratory of Microecology-Immune Regulatory Network and Related Diseases, Jiamusi 154007, Heilongjiang, China; Basic Medical College, Jiamusi University, Jiamusi 154007, Heilongjiang, China.
| | - Meng Gao
- Key Laboratory of Microecology-Immune Regulatory Network and Related Diseases, Jiamusi 154007, Heilongjiang, China; Basic Medical College, Jiamusi University, Jiamusi 154007, Heilongjiang, China.
| | - Chenxi Mu
- Key Laboratory of Microecology-Immune Regulatory Network and Related Diseases, Jiamusi 154007, Heilongjiang, China; Basic Medical College, Jiamusi University, Jiamusi 154007, Heilongjiang, China.
| | - Weijing Xu
- School of Public Health, Jiamusi University, Jiamusi 154007, Heilongjiang, China.
| | - Hui Xu
- Key Laboratory of Microecology-Immune Regulatory Network and Related Diseases, Jiamusi 154007, Heilongjiang, China.
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P2X7 Receptors in Astrocytes: A Switch for Ischemic Tolerance. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27123655. [PMID: 35744780 PMCID: PMC9228417 DOI: 10.3390/molecules27123655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 11/17/2022]
Abstract
A sub-lethal ischemic episode (preconditioning [PC]) protects neurons against a subsequent lethal ischemic injury. This phenomenon is known as ischemic tolerance. PC itself does not cause brain damage, but affects glial responses, especially astrocytes, and transforms them into an ischemia-resistant phenotype. P2X7 receptors (P2X7Rs) in astrocytes play essential roles in PC. Although P2X7Rs trigger inflammatory and toxic responses, PC-induced P2X7Rs in astrocytes function as a switch to protect the brain against ischemia. In this review, we focus on P2X7Rs and summarize recent developments on how astrocytes control P2X7Rs and what molecular mechanisms they use to induce ischemic tolerance.
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Kwon JK, Choi DJ, Yang H, Ko DW, Jou I, Park SM, Joe EH. Kir4.1 is coexpressed with stemness markers in activated astrocytes in the injured brain and a Kir4.1 inhibitor BaCl 2 negatively regulates neurosphere formation in culture. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2021; 25:565-574. [PMID: 34697267 PMCID: PMC8552822 DOI: 10.4196/kjpp.2021.25.6.565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 08/10/2021] [Accepted: 09/07/2021] [Indexed: 11/15/2022]
Abstract
Astrocytes are activated in response to brain damage. Here, we found that expression of Kir4.1, a major potassium channel in astrocytes, is increased in activated astrocytes in the injured brain together with upregulation of the neural stem cell markers, Sox2 and Nestin. Expression of Kir4.1 was also increased together with that of Nestin and Sox2 in neurospheres formed from dissociated P7 mouse brains. Using the Kir4.1 blocker BaCl2 to determine whether Kir4.1 is involved in acquisition of stemness, we found that inhibition of Kir4.1 activity caused a concentration-dependent increase in sphere size and Sox2 levels, but had little effect on Nestin levels. Moreover, induction of differentiation of cultured neural stem cells by withdrawing epidermal growth factor and fibroblast growth factor from the culture medium caused a sharp initial increase in Kir4.1 expression followed by a decrease, whereas Sox2 and Nestin levels continuously decreased. Inhibition of Kir4.1 had no effect on expression levels of Sox2 or Nestin, or the astrocyte and neuron markers glial fibrillary acidic protein and β-tubulin III, respectively. Taken together, these results indicate that Kir4.1 may control gain of stemness but not differentiation of stem cells.
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Affiliation(s)
- Jae-Kyung Kwon
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon 16499, Korea
| | - Dong-Joo Choi
- Department of Pharmacology, Ajou University School of Medicine, Suwon 16499, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 16499, Korea
| | - Haijie Yang
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon 16499, Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon 16499, Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon 16499, Korea
| | - Dong Wan Ko
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon 16499, Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon 16499, Korea
| | - Ilo Jou
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon 16499, Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon 16499, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 16499, Korea
| | - Sang Myun Park
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon 16499, Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon 16499, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 16499, Korea
| | - Eun-Hye Joe
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon 16499, Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon 16499, Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon 16499, Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon 16499, Korea.,Department of Brain Science, Ajou University School of Medicine, Suwon 16499, Korea
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6
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An J, Yang H, Yang E, Chung S, Kim DY, Jou I, Park SM, Kim BG, Chwae YJ, Joe EH. Dying neurons conduct repair processes in the injured brain through osteopontin expression in cooperation with infiltrated blood monocytes. Glia 2020; 69:1037-1052. [PMID: 33300228 DOI: 10.1002/glia.23947] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 11/28/2020] [Accepted: 11/29/2020] [Indexed: 12/18/2022]
Abstract
The brain has an intrinsic capacity to repair injury, but the specific mechanisms are largely unknown. In this study, we found that, despite their incipient death, damaged neurons play a key repair role with the help of monocytes infiltrated from blood. Monocytes phagocytosed damaged and/or dying neurons that expressed osteopontin (OPN), with possible subsequent activation of their inflammasome pathway, resulting in pyroptosis. During this process, monocytes released CD63-positive exosome-like vesicles containing OPN. Importantly, following the exosome-like vesicles, neuron and astrocyte processes elongated toward the injury core. In addition, exosomes prepared from the injured brain contained OPN, and enhanced neurite outgrowth of cultured neurons in an OPN-dependent manner. Thus, our results introduce the concept that neurons in the injured brain that are destined to die perceive the stressful condition and begin the regeneration processes through induction of OPN, ultimately executing the repair process with the help of monocytes recruited from the circulation.
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Affiliation(s)
- Jiawei An
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea
| | - Haijie Yang
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea
| | - Esther Yang
- Department of Anatomy, Korea University College of Medicine, Seoul, South Korea
| | - Sooyoung Chung
- Center for Neuroscience, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea
| | - Dae-Yong Kim
- Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, Seoul, South Korea
| | - Ilo Jou
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea
| | - Sang Myun Park
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea
| | - Byung Gon Kim
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Department of Brain Science, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Department of Neurology, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea
| | - Yong-Joon Chwae
- Department of Microbiology, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea
| | - Eun-Hye Joe
- Neuroscience Graduate Program, Department of Biomedical Sciences, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Department of Pharmacology, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Center for Convergence Research of Neurological Disorders, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea.,Department of Brain Science, Ajou University School of Medicine, Suwon, Kyunggi-do, South Korea
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Shokoples BG, Paradis P, Schiffrin EL. P2X7 Receptors: An Untapped Target for the Management of Cardiovascular Disease. Arterioscler Thromb Vasc Biol 2020; 41:186-199. [PMID: 32998520 PMCID: PMC7752223 DOI: 10.1161/atvbaha.120.315116] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chronic low-grade inflammation contributes to the development of several diseases, including cardiovascular disease. Adequate strategies to target inflammation in cardiovascular disease are in their infancy and remain an avenue of great interest. The purinergic receptor P2X7 is a ubiquitously expressed receptor that predominately mediates inflammation and cellular death. P2X7 is a ligand-gated cation channel that is activated in response to high concentrations of extracellular ATP, triggering the assembly and activation of the NLRP3 (nuclear oligomerization domain like receptor family pyrin domain containing 3) inflammasome and subsequent release of proinflammatory cytokines IL (interleukin)-1β and IL-18. Increased P2X7 activation and IL-1β and IL-18 concentrations have been implicated in the development of many cardiovascular conditions including hypertension, atherosclerosis, ischemia/reperfusion injury, and heart failure. P2X7 receptor KO (knockout) mice exhibit a significant attenuation of the inflammatory response, which corresponds with reduced disease severity. P2X7 antagonism blunts blood pressure elevation in hypertension and progression of atherosclerosis in animal models. IL-1β and IL-18 inhibition has shown efficacy in clinical trials reducing major adverse cardiac events, including myocardial infarction, and heart failure. With several P2X7 antagonists available with proven safety margins, P2X7 antagonism could represent an untapped potential for therapeutic intervention in cardiovascular disorders.
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Affiliation(s)
- Brandon G. Shokoples
- Vascular and Hypertension Research Unit, Lady Davis Institute for Medical Research (B.G.S., P.P., E.L.S.), Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Quebec, Canada
| | - Pierre Paradis
- Vascular and Hypertension Research Unit, Lady Davis Institute for Medical Research (B.G.S., P.P., E.L.S.), Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Quebec, Canada
| | - Ernesto L. Schiffrin
- Vascular and Hypertension Research Unit, Lady Davis Institute for Medical Research (B.G.S., P.P., E.L.S.), Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Quebec, Canada
- Department of Medicine (E.L.S.), Sir Mortimer B. Davis-Jewish General Hospital, McGill University, Montreal, Quebec, Canada
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8
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Yang H, An J, Choi I, Lee K, Park SM, Jou I, Joe EH. Region-specific astrogliosis: differential vessel formation contributes to different patterns of astrogliosis in the cortex and striatum. Mol Brain 2020; 13:103. [PMID: 32698847 PMCID: PMC7374828 DOI: 10.1186/s13041-020-00642-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 07/14/2020] [Indexed: 11/10/2022] Open
Abstract
Brain injury causes astrocytes to become reactive (astrogliosis). In this study, we compared astrogliosis in acutely injured cortex and striatum of adult FVB/N mice induced by stereotaxic injection of ATP, a component of danger-associated molecular patterns (DAMPs). Interestingly, MR analysis showed that same amount of ATP induced smaller damage in the cortex than in the striatum. However, in histological analysis, thick and dense scar-like astrogliosis was found in the injured cortex near meninges within 2 wk., but not in other regions, including the striatum and even the cortex near the corpus callosum for up to 30 d. There was little regional difference in the number of Ki67(+)-proliferating astrocytes or mRNA expression of inflammatory cytokines. The most prominent difference between regions with and without scar-like astrogliosis was blood vessel formation. Blood vessels highly expressing collagen 1A1 formed densely near meninges, and astrocytes converged on them. In other regions, however, both blood vessels and astrocytes were relatively evenly distributed. Consistent with this, inhibition of blood vessel formation with the vascular endothelial growth factor (VEGF)-blocking antibody, Avastin, attenuated scar-like astrogliosis near meninges. These results indicate that region-specific astrogliosis occurs following brain injury, and that blood vessel formation plays a critical role in scar formation.
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Affiliation(s)
- Haijie Yang
- Department of Pharmacology/Neuroscience Graduate Program, National Research Lab of Brain Inflammation, Ajou University School of Medicine, Worldcup-ro 164, Youngtong-gu, Suwon, Kyunggi-do, 16499, South Korea.,Department of Brain Science, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea
| | - Jiawei An
- Department of Pharmacology/Neuroscience Graduate Program, National Research Lab of Brain Inflammation, Ajou University School of Medicine, Worldcup-ro 164, Youngtong-gu, Suwon, Kyunggi-do, 16499, South Korea.,Department of Brain Science, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea.,Department of Biomedical Sciences, Neuroscience Graduate Program, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea
| | - Insup Choi
- Department of Pharmacology/Neuroscience Graduate Program, National Research Lab of Brain Inflammation, Ajou University School of Medicine, Worldcup-ro 164, Youngtong-gu, Suwon, Kyunggi-do, 16499, South Korea.,Department of Brain Science, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea.,Department of Biomedical Sciences, Neuroscience Graduate Program, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea
| | - Kihwang Lee
- Department of Ophthalmology, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea
| | - Sang-Myun Park
- Department of Pharmacology/Neuroscience Graduate Program, National Research Lab of Brain Inflammation, Ajou University School of Medicine, Worldcup-ro 164, Youngtong-gu, Suwon, Kyunggi-do, 16499, South Korea.,Department of Biomedical Sciences, Neuroscience Graduate Program, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea
| | - Ilo Jou
- Department of Pharmacology/Neuroscience Graduate Program, National Research Lab of Brain Inflammation, Ajou University School of Medicine, Worldcup-ro 164, Youngtong-gu, Suwon, Kyunggi-do, 16499, South Korea.,Department of Biomedical Sciences, Neuroscience Graduate Program, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea.,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea
| | - Eun-Hye Joe
- Department of Pharmacology/Neuroscience Graduate Program, National Research Lab of Brain Inflammation, Ajou University School of Medicine, Worldcup-ro 164, Youngtong-gu, Suwon, Kyunggi-do, 16499, South Korea. .,Department of Brain Science, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea. .,Department of Biomedical Sciences, Neuroscience Graduate Program, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea. .,Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Worldcup-ro 164, Suwon, Kyunggi-do, 16499, South Korea.
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9
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Nguyen HM, di Lucente J, Chen YJ, Cui Y, Ibrahim RH, Pennington MW, Jin LW, Maezawa I, Wulff H. Biophysical basis for Kv1.3 regulation of membrane potential changes induced by P2X4-mediated calcium entry in microglia. Glia 2020; 68:2377-2394. [PMID: 32525239 PMCID: PMC7540709 DOI: 10.1002/glia.23847] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 04/17/2020] [Accepted: 05/07/2020] [Indexed: 12/02/2022]
Abstract
Microglia‐mediated inflammation exerts adverse effects in ischemic stroke and in neurodegenerative disorders such as Alzheimer's disease (AD). Expression of the voltage‐gated potassium channel Kv1.3 is required for microglia activation. Both genetic deletion and pharmacological inhibition of Kv1.3 are effective in reducing microglia activation and the associated inflammatory responses, as well as in improving neurological outcomes in animal models of AD and ischemic stroke. Here we sought to elucidate the molecular mechanisms underlying the therapeutic effects of Kv1.3 inhibition, which remain incompletely understood. Using a combination of whole‐cell voltage‐clamp electrophysiology and quantitative PCR (qPCR), we first characterized a stimulus‐dependent differential expression pattern for Kv1.3 and P2X4, a major ATP‐gated cationic channel, both in vitro and in vivo. We then demonstrated by whole‐cell current‐clamp experiments that Kv1.3 channels contribute not only to setting the resting membrane potential but also play an important role in counteracting excessive membrane potential changes evoked by depolarizing current injections. Similarly, the presence of Kv1.3 channels renders microglia more resistant to depolarization produced by ATP‐mediated P2X4 receptor activation. Inhibiting Kv1.3 channels with ShK‐223 completely nullified the ability of Kv1.3 to normalize membrane potential changes, resulting in excessive depolarization and reduced calcium transients through P2X4 receptors. Our report thus links Kv1.3 function to P2X4 receptor‐mediated signaling as one of the underlying mechanisms by which Kv1.3 blockade reduces microglia‐mediated inflammation. While we could confirm previously reported differences between males and females in microglial P2X4 expression, microglial Kv1.3 expression exhibited no gender differences in vitro or in vivo. Main Points The voltage‐gated K+ channel Kv1.3 regulates microglial membrane potential. Inhibition of Kv1.3 depolarizes microglia and reduces calcium entry mediated by P2X4 receptors by dissipating the electrochemical driving force for calcium.
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Affiliation(s)
- Hai M Nguyen
- Department of Pharmacology, University of California, Davis, California, USA
| | - Jacopo di Lucente
- Department of Pathology and Laboratory Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Sacramento, California, USA
| | - Yi-Je Chen
- Department of Pharmacology, University of California, Davis, California, USA
| | - Yanjun Cui
- Department of Pharmacology, University of California, Davis, California, USA
| | - Rania H Ibrahim
- Department of Pharmacology, University of California, Davis, California, USA
| | | | - Lee-Way Jin
- Department of Pathology and Laboratory Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Sacramento, California, USA
| | - Izumi Maezawa
- Department of Pathology and Laboratory Medicine and M.I.N.D. Institute, University of California Davis Medical Center, Sacramento, California, USA
| | - Heike Wulff
- Department of Pharmacology, University of California, Davis, California, USA
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10
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Kanellopoulos JM, Delarasse C. Pleiotropic Roles of P2X7 in the Central Nervous System. Front Cell Neurosci 2019; 13:401. [PMID: 31551714 PMCID: PMC6738027 DOI: 10.3389/fncel.2019.00401] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 08/19/2019] [Indexed: 12/16/2022] Open
Abstract
The purinergic receptor P2X7 is expressed in neural and immune cells known to be involved in neurological diseases. Its ligand, ATP, is a signaling molecule that can act as a neurotransmitter in physiological conditions or as a danger signal when released in high amount by damaged/dying cells or activated glial cells. Thus, ATP is a danger-associated molecular pattern. Binding of ATP by P2X7 leads to the activation of different biochemical pathways, depending on the physiological or pathological environment. The aim of this review is to discuss various functions of P2X7 in the immune and central nervous systems. We present evidence that P2X7 may have a detrimental or beneficial role in the nervous system, in the context of neurological pathologies: epilepsy, Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis, age-related macular degeneration and cerebral artery occlusion.
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Affiliation(s)
| | - Cécile Delarasse
- Inserm, Sorbonne Université, CNRS, Institut de la Vision, Paris, France
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11
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Jank L, Pinto-Espinoza C, Duan Y, Koch-Nolte F, Magnus T, Rissiek B. Current Approaches and Future Perspectives for Nanobodies in Stroke Diagnostic and Therapy. Antibodies (Basel) 2019; 8:antib8010005. [PMID: 31544811 PMCID: PMC6640704 DOI: 10.3390/antib8010005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/20/2018] [Accepted: 12/27/2018] [Indexed: 12/15/2022] Open
Abstract
Antibody-based biologics are the corner stone of modern immunomodulatory therapy. Though highly effective in dampening systemic inflammatory processes, their large size and Fc-fragment mediated effects hamper crossing of the blood brain barrier (BBB). Nanobodies (Nbs) are single domain antibodies derived from llama or shark heavy-chain antibodies and represent a new generation of biologics. Due to their small size, they display excellent tissue penetration capacities and can be easily modified to adjust their vivo half-life for short-term diagnostic or long-term therapeutic purposes or to facilitate crossing of the BBB. Furthermore, owing to their characteristic binding mode, they are capable of antagonizing receptors involved in immune signaling and of neutralizing proinflammatory mediators, such as cytokines. These qualities combined make Nbs well-suited for down-modulating neuroinflammatory processes that occur in the context of brain ischemia. In this review, we summarize recent findings on Nbs in preclinical stroke models and how they can be used as diagnostic and therapeutic reagents. We further provide a perspective on the design of innovative Nb-based treatment protocols to complement and improve stroke therapy.
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Affiliation(s)
- Larissa Jank
- Department of Neurology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Carolina Pinto-Espinoza
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Yinghui Duan
- Department of Neurology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Friedrich Koch-Nolte
- Institute of Immunology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Tim Magnus
- Department of Neurology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
| | - Björn Rissiek
- Department of Neurology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
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12
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Cooperation between NMDA-Type Glutamate and P2 Receptors for Neuroprotection during Stroke: Combining Astrocyte and Neuronal Protection. ACTA ACUST UNITED AC 2018. [DOI: 10.3390/neuroglia1010005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Excitotoxicity is the principle mechanism of acute injury during stroke. It is defined as the unregulated accumulation of excitatory neurotransmitters such as glutamate within the extracellular space, leading to over-activation of receptors, ionic disruption, cell swelling, cytotoxic Ca2+ elevation and a feed-forward loop where membrane depolarisation evokes further neurotransmitter release. Glutamate-mediated excitotoxicity is well documented in neurons and oligodendrocytes but drugs targeting glutamate excitotoxicity have failed clinically which may be due to their inability to protect astrocytes. Astrocytes make up ~50% of the brain volume and express high levels of P2 adenosine triphosphate (ATP)-receptors which have excitotoxic potential, suggesting that glutamate and ATP may mediate parallel excitotoxic cascades in neurons and astrocytes, respectively. Mono-cultures of astrocytes expressed an array of P2X and P2Y receptors can produce large rises in [Ca2+]i; mono-cultured neurons showed lower levels of functional P2 receptors. Using high-density 1:1 neuron:astrocyte co-cultures, ischemia (modelled as oxygen-glucose deprivation: OGD) evoked a rise in extracellular ATP, while P2 blockers were highly protective of both cell types. GluR blockers were only protective of neurons. Neither astrocyte nor neuronal mono-cultures showed significant ATP release during OGD, showing that cell type interactions are required for ischemic release. P2 blockers were also protective in normal-density co-cultures, while low doses of combined P2/GluR blockers where highly protective. These results highlight the potential of combined P2/GluR block for protection of neurons and glia.
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13
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Purine Signaling and Microglial Wrapping. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 949:147-165. [PMID: 27714688 DOI: 10.1007/978-3-319-40764-7_7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Microglial cells are highly dynamic cells with processes continuously moving to survey the surrounding territory. Microglia possess a broad variety of surface receptors and subtle changes in their microenvironment cause microglial cell processes to extend, retract, and interact with neuronal synaptic contacts. When the nervous system is disturbed, microglia activate, proliferate, and migrate to sites of injury in response to alert signals. Released nucleotides like ATP and UTP are among the wide range of molecules promoting microglial activation and guiding their migration and phagocytic function. The increased concentration of nucleotides in the extracellular space could be involved in the microglial wrapping found around injured neurons in various pathological conditions, especially after peripheral axotomy. Microglial wrappings isolate injured neurons from synaptic inputs and facilitate the molecular dialog between endangered or injured neurons and activated microglia. Astrocytes may also participate in neuronal ensheathment. Degradation of ATP by microglial ecto-nucleotidases and the expression of various purine receptors might be decisive in regulating the function of enwrapping glial cells and in determining the fate of damaged neurons, which may die or may regenerate their axons and survive.
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14
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Zhu B, Lu Y, Chen L, Yu B, Liu Y, Song M, Hang T. Identification and characterization of related substances in EVT-401 by hyphenated LC-MS techniques. J Pharm Anal 2017; 7:223-230. [PMID: 29404042 PMCID: PMC5790700 DOI: 10.1016/j.jpha.2017.03.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/28/2017] [Accepted: 03/28/2017] [Indexed: 11/23/2022] Open
Abstract
A sensitive and selective method was developed for the separation and characterization of related substances (RSs) in EVT-401 by hyphenated LC–MS techniques. Complete separation of the RSs was achieved with an Inertsil ODS-SP column (250 mm×4.6 mm, 5 µm) by linear gradient elution using a mobile phase consisting of 0.2% formic acid solution, methanol and acetonitrile. EVT-401 was found to be susceptible to acid, alkaline and oxidative stresses, while relatively stable under photolytic and thermal dry stress conditions. Fourteen RSs including six process-related substances and eight degradation products were detected and identified in EVT-401 with positive ESI high-resolution TOF-MS analysis of their parent ions and the corresponding product mass spectra elucidation, and some of them were further verified by chemical synthesis and NMR spectroscopy. The specific LC–MS method developed for separation, identification and characterization of RSs is valuable for EVT-401 manufacturing process optimization and quality control.
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Affiliation(s)
- Binan Zhu
- Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education; Department of Pharmaceutical Analysis, China Pharmaceutical University, Nanjing 210009, China
| | - Yuting Lu
- Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education; Department of Pharmaceutical Analysis, China Pharmaceutical University, Nanjing 210009, China
| | - Leilin Chen
- Department of Chemical Drug Control, Hubei Institute for Food and Drug Control, Wuhan 430074, China
| | - Binbin Yu
- Department of Pharmacy, Taizhou First People's Hospital, Taizhou 318200, China
| | - Yuexin Liu
- Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education; Department of Pharmaceutical Analysis, China Pharmaceutical University, Nanjing 210009, China
| | - Min Song
- Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education; Department of Pharmaceutical Analysis, China Pharmaceutical University, Nanjing 210009, China
| | - Taijun Hang
- Key Laboratory of Drug Quality Control and Pharmacovigilance, Ministry of Education; Department of Pharmaceutical Analysis, China Pharmaceutical University, Nanjing 210009, China
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15
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Role of purinergic signaling in experimental pneumococcal meningitis. Sci Rep 2017; 7:44625. [PMID: 28300164 PMCID: PMC5353597 DOI: 10.1038/srep44625] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 02/10/2017] [Indexed: 12/25/2022] Open
Abstract
Excessive neutrophilic inflammation contributes to brain pathology and adverse outcome in pneumococcal meningitis (PM). Recently, we identified the NLRP3 inflammasome/interleukin (IL)-1β pathway as a key driver of inflammation in PM. A critical membrane receptor for NLRP3 inflammasome activation is the ATP-activated P2 purinoceptor (P2R) P2X7. Thus, we hypothesized involvement of ATP and P2Rs in PM. The functional role of ATP was investigated in a mouse meningitis model using P2R antagonists. Brain expression of P2Rs was assessed by RT-PCR. ATP levels were determined in murine CSF and cell culture experiments. Treatment with the P2R antagonists suramin or brilliant blue G did not have any impact on disease course. This lack of effect might be attributed to meningitis-associated down-regulation of brain P2R expression and/or a drop of cerebrospinal fluid (CSF) ATP, as demonstrated by RT-PCR and ATP analyses. Supplemental cell culture experiments suggest that the reduction in CSF ATP is, at least partly, due to ATP hydrolysis by ectonucleotidases of neutrophils and macrophages. In conclusion, this study suggests that ATP-P2R signaling is only of minor or even no significance in PM. This may be explained by down-regulation of P2R expression and decreased CSF ATP levels.
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McCann SK, Cramond F, Macleod MR, Sena ES. Systematic Review and Meta-Analysis of the Efficacy of Interleukin-1 Receptor Antagonist in Animal Models of Stroke: an Update. Transl Stroke Res 2016; 7:395-406. [PMID: 27526101 PMCID: PMC5014900 DOI: 10.1007/s12975-016-0489-z] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/25/2016] [Accepted: 07/28/2016] [Indexed: 02/04/2023]
Abstract
Interleukin-1 receptor antagonist (IL-1 RA) is an anti-inflammatory protein used clinically to treat rheumatoid arthritis and is considered a promising candidate therapy for stroke. Here, we sought to update the existing systematic review and meta-analysis of IL-1 RA in models of ischaemic stroke, published in 2009, to assess efficacy, the range of circumstances in which efficacy has been tested and whether the data appear to be confounded due to reported study quality and publication bias. We included 25 sources of data, 11 of which were additional to the original review. Overall, IL-1 RA reduced infarct volume by 36.2 % (95 % confidence interval 31.6-40.7, n = 76 comparisons from 1283 animals). Assessments for publication bias suggest 30 theoretically missing studies which reduce efficacy to 21.9 % (17.3-26.4). Efficacy was higher where IL-1 RA was administered directly into the ventricles rather than peripherally, and studies not reporting allocation concealment during the induction of ischaemia reported larger treatment effects. The preclinical data supporting IL-1 RA as a candidate therapy for ischaemic stroke have improved. The reporting of measures to reduce the risk of bias has improved substantially in this update, and studies now include the use of animals with relevant co-morbidities.
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Affiliation(s)
- Sarah K McCann
- Centre for Clinical Brain Sciences, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Fala Cramond
- Centre for Clinical Brain Sciences, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Malcolm R Macleod
- Centre for Clinical Brain Sciences, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Emily S Sena
- Centre for Clinical Brain Sciences, University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
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17
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Stoler O, Fleidervish IA. Functional implications of axon initial segment cytoskeletal disruption in stroke. Acta Pharmacol Sin 2016; 37:75-81. [PMID: 26687934 DOI: 10.1038/aps.2015.107] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 10/28/2015] [Indexed: 12/19/2022] Open
Abstract
Axon initial segment (AIS) is the proximal part of the axon, which is not covered with a myelin sheath and possesses a distinctive, specialized assembly of voltage-gated ion channels and associated proteins. AIS plays critical roles in synaptic integration and action potential generation in central neurons. Recent evidence shows that stroke causes rapid, irreversible calpain-mediated proteolysis of the AIS cytoskeleton of neurons surrounding the ischemic necrotic core. A better understanding of the molecular mechanisms underlying this "non-lethal" neuronal damage might provide new therapeutic strategies for improving stroke outcome. Here, we present a brief overview of the structure and function of the AIS. We then discuss possible mechanisms underlying stroke-induced AIS damage, including the roles of calpains and possible sources of Ca(2+) ions, which are necessary for the activation of calpains. Finally, we discuss the potential functional implications of the loss of the AIS cytoskeleton and ion channel clusters for neuronal excitability.
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18
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Pedata F, Dettori I, Coppi E, Melani A, Fusco I, Corradetti R, Pugliese AM. Purinergic signalling in brain ischemia. Neuropharmacology 2015; 104:105-30. [PMID: 26581499 DOI: 10.1016/j.neuropharm.2015.11.007] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 11/04/2015] [Accepted: 11/06/2015] [Indexed: 12/18/2022]
Abstract
Ischemia is a multifactorial pathology characterized by different events evolving in the time. After ischemia a primary damage due to the early massive increase of extracellular glutamate is followed by activation of resident immune cells, i.e microglia, and production or activation of inflammation mediators. Protracted neuroinflammation is now recognized as the predominant mechanism of secondary brain injury progression. Extracellular concentrations of ATP and adenosine in the brain increase dramatically during ischemia in concentrations able to stimulate their respective specific P2 and P1 receptors. Both ATP P2 and adenosine P1 receptor subtypes exert important roles in ischemia. Although adenosine exerts a clear neuroprotective effect through A1 receptors during ischemia, the use of selective A1 agonists is hampered by undesirable peripheral effects. Evidence up to now in literature indicate that A2A receptor antagonists provide protection centrally by reducing excitotoxicity, while agonists at A2A (and possibly also A2B) and A3 receptors provide protection by controlling massive infiltration and neuroinflammation in the hours and days after brain ischemia. Among P2X receptors most evidence indicate that P2X7 receptor contribute to the damage induced by the ischemic insult due to intracellular Ca(2+) loading in central cells and facilitation of glutamate release. Antagonism of P2X7 receptors might represent a new treatment to attenuate brain damage and to promote proliferation and maturation of brain immature resident cells that can promote tissue repair following cerebral ischemia. Among P2Y receptors, antagonists of P2Y12 receptors are of value because of their antiplatelet activity and possibly because of additional anti-inflammatory effects. Moreover strategies that modify adenosine or ATP concentrations at injury sites might be of value to limit damage after ischemia. This article is part of the Special Issue entitled 'Purines in Neurodegeneration and Neuroregeneration'.
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Affiliation(s)
- Felicita Pedata
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy.
| | - Ilaria Dettori
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Elisabetta Coppi
- Department of Health Sciences, University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Alessia Melani
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Irene Fusco
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Renato Corradetti
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
| | - Anna Maria Pugliese
- Department of Neuroscience, Psychology, Drug Research and Child Health (NEUROFARBA), University of Florence, Viale Pieraccini, 6, 50139 Florence, Italy
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19
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Kim JY, Ko AR, Kim JE. P2X7 receptor-mediated PARP1 activity regulates astroglial death in the rat hippocampus following status epilepticus. Front Cell Neurosci 2015; 9:352. [PMID: 26388738 PMCID: PMC4560025 DOI: 10.3389/fncel.2015.00352] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/24/2015] [Indexed: 01/14/2023] Open
Abstract
Poly(ADP-ribose) polymerase-1 (PARP1) plays a regulatory role in apoptosis, necrosis, and other cellular processes after injury. Recently, we revealed that PARP1 regulates the differential neuronal/astroglial responses to pilocarpine-induced status epilepticus (SE) in the distinct brain regions. In addition, P2X7 receptor (P2X7R), an ATP-gated ion channel, activation accelerates astroglial apoptosis, while it attenuates clasmatodendrosis (lysosome-derived autophagic astroglial death). Therefore, we investigated whether P2X7R regulates regional specific astroglial PARP1 expression/activation in response to SE. In the present study, P2X7R activation exacerbates SE-induced astroglial apoptosis, while P2X7R inhibition attenuates it accompanied by increasing PARP1 activity in the molecular layer of the dentate gyrus following SE. In the CA1 region, however, P2X7R inhibition deteriorates SE-induced clasmatodendrosis via PARP1 activation following SE. Taken together, our findings suggest that P2X7R function may affect SE-induced astroglial death by regulating PARP1 activation/expression in regional-specific manner. Therefore, the selective modulation of P2X7R-mediated PARP1 functions may be a considerable strategy for controls in various types of cell deaths.
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Affiliation(s)
- Ji Yang Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University Okcheon-dong, Chuncheon, South Korea
| | - Ah-Reum Ko
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University Okcheon-dong, Chuncheon, South Korea
| | - Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University Okcheon-dong, Chuncheon, South Korea
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20
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Seeland S, Kettiger H, Murphy M, Treiber A, Giller J, Kiss A, Sube R, Krähenbühl S, Hafner M, Huwyler J. ATP-induced cellular stress and mitochondrial toxicity in cells expressing purinergic P2X7 receptor. Pharmacol Res Perspect 2015; 3:e00123. [PMID: 26038699 PMCID: PMC4448979 DOI: 10.1002/prp2.123] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/10/2014] [Accepted: 12/19/2014] [Indexed: 12/15/2022] Open
Abstract
Under pathological conditions, the purinergic P2X7 receptor is activated by elevated concentrations of extracellular ATP. Thereby, the receptor forms a slowly dilating pore, allowing cations and, upon prolonged stimulation, large molecules to enter the cell. This process has a strong impact on cell signaling, metabolism, and viability. This study aimed to establish a link between gradual P2X7 activation and pharmacological endpoints including oxidative stress, hydrogen peroxide generation, and cytotoxicity. Mechanisms of cellular stress and cytotoxicity were studied in P2X7-transfected HEK293 cells. We performed real-time monitoring of metabolic and respiratory activity of cells expressing the P2X7-receptor protein using a cytosensor system. Agonistic effects were monitored using exogenously applied ATP or the stable analogue BzATP. Oxidative stress induced by ATP or BzATP in target cells was monitored by hydrogen peroxide release in human mononuclear blood cells. P2X7-receptor activation was studied by patch-clamp experiments using a primary mouse microglia cell line. Stimulation of the P2X7 receptor leads to ion influx, metabolic activation of target cells, and ultimately cytotoxicity. Conversion of the P2X7 receptor from a small cation channel to a large pore occurring under prolonged stimulation can be monitored in real time covering a time frame of milliseconds to hours. Selectivity of the effects can be demonstrated using the selective P2X7-receptor antagonist AZD9056. Our findings established a direct link between P2X7-receptor activation by extracellular ATP or BzATP and cellular events culminating in cytotoxicity. Mechanisms of toxicity include metabolic and oxidative stress, increase in intracellular calcium concentration and disturbance of mitochondrial membrane potential. Mitochondrial toxicity is suggested to be a key event leading to cell death.
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Affiliation(s)
- Swen Seeland
- Actelion Pharmaceuticals Ltd Gewerbestrasse 16, 4123, Allschwil, Switzerland ; Institute for Molecular and Cell Biology, University of Applied Science Paul-Wittsack-Strasse 10, 68163, Mannheim, Germany
| | - Hélène Kettiger
- Division of Pharmaceutical Technology, Department of Pharmaceutical Sciences, University of Basel Klingelbergstrasse 50, 4056, Basel, Switzerland
| | - Mark Murphy
- Actelion Pharmaceuticals Ltd Gewerbestrasse 16, 4123, Allschwil, Switzerland
| | - Alexander Treiber
- Actelion Pharmaceuticals Ltd Gewerbestrasse 16, 4123, Allschwil, Switzerland
| | - Jasmin Giller
- Actelion Pharmaceuticals Ltd Gewerbestrasse 16, 4123, Allschwil, Switzerland
| | - Andrea Kiss
- Actelion Pharmaceuticals Ltd Gewerbestrasse 16, 4123, Allschwil, Switzerland
| | - Romain Sube
- Actelion Pharmaceuticals Ltd Gewerbestrasse 16, 4123, Allschwil, Switzerland
| | - Stephan Krähenbühl
- Division of Clinical Pharmacology and Toxicology, University Hospital of Basel 4056, Basel, Switzerland
| | - Mathias Hafner
- Institute for Molecular and Cell Biology, University of Applied Science Paul-Wittsack-Strasse 10, 68163, Mannheim, Germany
| | - Jörg Huwyler
- Division of Pharmaceutical Technology, Department of Pharmaceutical Sciences, University of Basel Klingelbergstrasse 50, 4056, Basel, Switzerland
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21
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Bartlett R, Stokes L, Sluyter R. The P2X7 receptor channel: recent developments and the use of P2X7 antagonists in models of disease. Pharmacol Rev 2015; 66:638-75. [PMID: 24928329 DOI: 10.1124/pr.113.008003] [Citation(s) in RCA: 313] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The P2X7 receptor is a trimeric ATP-gated cation channel found predominantly, but not exclusively, on immune cells. P2X7 activation results in a number of downstream events, including the release of proinflammatory mediators and cell death and proliferation. As such, P2X7 plays important roles in various inflammatory, immune, neurologic and musculoskeletal disorders. This review focuses on the use of P2X7 antagonists in rodent models of neurologic disease and injury, inflammation, and musculoskeletal and other disorders. The cloning and characterization of human, rat, mouse, guinea pig, dog, and Rhesus macaque P2X7, as well as recent observations regarding the gating and permeability of P2X7, are discussed. Furthermore, this review discusses polymorphic and splice variants of P2X7, as well as the generation and use of P2X7 knockout mice. Recent evidence for emerging signaling pathways downstream of P2X7 activation and the growing list of negative and positive modulators of P2X7 activation and expression are also described. In addition, the use of P2X7 antagonists in numerous rodent models of disease is extensively summarized. Finally, the use of P2X7 antagonists in clinical trials in humans and future directions exploring P2X7 as a therapeutic target are described.
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Affiliation(s)
- Rachael Bartlett
- School of Biological Sciences, University of Wollongong, New South Wales, Australia and Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia (R.B., R.S.); and Health Innovations Research Institute, School of Medical Sciences, RMIT University, Bundoora, Victoria, Australia (L.S.)
| | - Leanne Stokes
- School of Biological Sciences, University of Wollongong, New South Wales, Australia and Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia (R.B., R.S.); and Health Innovations Research Institute, School of Medical Sciences, RMIT University, Bundoora, Victoria, Australia (L.S.)
| | - Ronald Sluyter
- School of Biological Sciences, University of Wollongong, New South Wales, Australia and Illawarra Health and Medical Research Institute, Wollongong, New South Wales, Australia (R.B., R.S.); and Health Innovations Research Institute, School of Medical Sciences, RMIT University, Bundoora, Victoria, Australia (L.S.)
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22
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Trendelenburg G. Molecular regulation of cell fate in cerebral ischemia: role of the inflammasome and connected pathways. J Cereb Blood Flow Metab 2014; 34:1857-67. [PMID: 25227604 PMCID: PMC4269743 DOI: 10.1038/jcbfm.2014.159] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 08/13/2014] [Accepted: 08/25/2014] [Indexed: 12/19/2022]
Abstract
Analogous to Toll-like receptors, NOD-like receptors represent a class of pattern recognition receptors, which are cytosolic and constitute part of different inflammasomes. These large protein complexes are activated not only by different pathogens, but also by sterile inflammation or by specific metabolic conditions. Mutations can cause hereditary autoinflammatory systemic diseases, and inflammasome activation has been linked to many multifactorial diseases, such as diabetes or cardiovascular diseases. Increasing data also support an important role in different central nervous diseases such as stroke. Thus, the current knowledge of the functional role of this intracellular 'master switch' of inflammation is discussed with a focus on its role in ischemic stroke, neurodegeneration, and also with regard to the recent data which argues for a relevant role in other organs or biologic systems which influence stroke incidence or prognosis.
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Affiliation(s)
- George Trendelenburg
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
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23
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The impact of the P2X7 receptor antagonist A-804598 on neuroimmune and behavioral consequences of stress. Behav Pharmacol 2014; 25:582-98. [DOI: 10.1097/fbp.0000000000000072] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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24
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Pathological potential of astroglial purinergic receptors. ADVANCES IN NEUROBIOLOGY 2014; 11:213-56. [PMID: 25236731 DOI: 10.1007/978-3-319-08894-5_11] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Acute brain injury and neurodegenerative disorders may result in astroglial activation. Astrocytes are able to determine the progression and outcome of these neuropathologies in a beneficial or detrimental way. Nucleotides, e.g. adenosine 5'-triphosphate (ATP), released after acute or chronic neuronal injury, are important mediators of glial activation and astrogliosis.Acute injury may cause significant changes in ATP balance, resulting in (1) a decline of intracellular ATP levels and (2) an increase in extracellular ATP concentrations via efflux from the intracellular space. The released ATP may have trophic effects, but can also act as a proinflammatory mediator or cytotoxic factor, inducing necrosis/apoptosis as a universal "danger" signal. Furthermore, ATP, primarily released from astrocytes, is a means of communication between neurons, glial cells, and intracerebral blood vessels.Astrocytes express a heterogeneous battery of purinergic ionotropic and metabotropic receptors (P2XRs and P2YRs, respectively) to respond to extracellular nucleotides.In this chapter, we summarize the contemporary knowledge on the pathological potential of P2Rs in relation to changes of astrocytic functions, determined by distinct molecular signaling cascades, in a variety of diseases. We discuss specific aspects of reactive astrogliosis, with respect to the involvement of prominent receptor subtypes, such as the P2X7 and P2Y1/2Rs. Examples of purinergic signaling of microglia, oligodendrocytes, and blood vessels under pathophysiological conditions will also be presented.The understanding of the pathological potential of purinergic signaling in "controlling and fine-tuning" of astrocytic responses is important for identifying possible therapeutic principles to treat acute and chronic central nervous system diseases.
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ATP signaling in brain: release, excitotoxicity and potential therapeutic targets. Cell Mol Neurobiol 2014; 35:1-6. [PMID: 25096398 DOI: 10.1007/s10571-014-0092-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Accepted: 07/19/2014] [Indexed: 10/24/2022]
Abstract
Adenosine 5'-triphosphate (ATP) is released as a genuine co-transmitter, or as a principal purinergic neurotransmitter, in an exocytotic and non-exocytotic manner. It activates ionotropic (P2X) and metabotropic (P2Y) receptors which mediate a plethora of functions in the brain. In particular, P2X7 receptor (P2X7R) are expressed in all brain cells and its activation can form a large pore allowing the passage of organic cations, the leakage of metabolites of up to 900 Da and the release of ATP itself. In turn, pannexins (Panx) are a family of proteins forming hemichannels that can release ATP. In this review, we summarize the progress in the understanding of the mechanisms of ATP release both in physiological and pathophysiological stages. We also provide data suggesting that P2X7R and pannexin 1 (Panx1) may form a large pore in cortical neurons as assessed by electrophysiology. Finally, the participation of calcium homeostasis modulator 1 is also suggested, another non-selective ion channel that can release ATP, and that could play a role in ischemic events, together with P2X7 and Panx1 during excitotoxicity by ATP.
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Kang SS, Keasey MP, Hagg T. P2X7 receptor inhibition increases CNTF in the subventricular zone, but not neurogenesis or neuroprotection after stroke in adult mice. Transl Stroke Res 2014; 4:533-45. [PMID: 24312160 DOI: 10.1007/s12975-013-0265-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Increasing endogenous ciliary neurotrophic factor (CNTF) expression with a pharmacological agent might be beneficial after stroke as CNTF both promotes neurogenesis and, separately, is neuroprotective. P2X7 purinergic receptor inhibition is neuroprotective in rats and increases CNTF release in rat CMT1A Schwann cells. We, first, investigated the role of P2X7 in regulating CNTF and neurogenesis in adult mouse subventricular zone (SVZ). CNTF expression was increased by daily intravenous injections of the P2X7 antagonist Brilliant Blue G (BBG) in naïve C57BL/6 or Balb/c mice over 3 days. Despite the ∼40-60 % increase or decrease in CNTF with BBG or the agonist BzATP, respectively, the number of proliferated BrdU+SVZ nuclei did not change. BBG failed to increase FGF2, which is involved in CNTF-regulated neurogenesis, but induced IL-6, LIF, and EGF, which are known to reduce SVZ proliferation. Injections of IL-6 next to the SVZ induced CNTF and FGF2, but not proliferation, suggesting that IL-6 counteracts their neurogenesis-inducing effects. Following ischemic injury of the striatum by middle cerebral artery occlusion (MCAO), a 3-day BBG treatment increased CNTF in the medial penumbra containing the SVZ. BBG also induced CNTF and LIF, which are known to be protective following stroke, in the whole striatum after MCAO, but not GDNF or BDNF. However, BBG treatment did not reduce the lesion area or apoptosis in the penumbra. Even so, this study shows that P2X7 can be targeted with systemic drug treatments to differentially regulate neurotrophic factors in the brain following stroke.
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Affiliation(s)
- Seong Su Kang
- Kentucky Spinal Cord Injury Research Center, University of Louisville, 511 South Floyd Street, MDR Building, Room 616, Louisville, KY 40292, USA; Department of Neurological Surgery, University of Louisville, Louisville, KY 40292, USA
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Wesseling H, Guest PC, Lee CM, Wong EH, Rahmoune H, Bahn S. Integrative proteomic analysis of the NMDA NR1 knockdown mouse model reveals effects on central and peripheral pathways associated with schizophrenia and autism spectrum disorders. Mol Autism 2014; 5:38. [PMID: 25061506 PMCID: PMC4109791 DOI: 10.1186/2040-2392-5-38] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 06/20/2014] [Indexed: 12/21/2022] Open
Abstract
Background Over the last decade, the transgenic N-methyl-D-aspartate receptor (NMDAR) NR1-knockdown mouse (NR1neo−/−) has been investigated as a glutamate hypofunction model for schizophrenia. Recent research has now revealed that the model also recapitulates cognitive and negative symptoms in the continuum of other psychiatric diseases, particularly autism spectrum disorders (ASD). As previous studies have mostly focussed on behavioural readouts, a molecular characterisation of this model will help to identify novel biomarkers or potential drug targets. Methods Here, we have used multiplex immunoassay analyses to investigate peripheral analyte alterations in serum of NR1neo−/− mice, as well as a combination of shotgun label-free liquid chromatography mass spectrometry, bioinformatic pathway analyses, and a shotgun-based 40-plex selected reaction monitoring (SRM) assay to investigate altered molecular pathways in the frontal cortex and hippocampus. All findings were cross compared to identify translatable findings between the brain and periphery. Results Multiplex immunoassay profiling led to identification of 29 analytes that were significantly altered in sera of NR1neo−/− mice. The highest magnitude changes were found for neurotrophic factors (VEGFA, EGF, IGF-1), apolipoprotein A1, and fibrinogen. We also found decreased levels of several chemokines. Following this, LC-MSE profiling led to identification of 48 significantly changed proteins in the frontal cortex and 41 in the hippocampus. In particular, MARCS, the mitochondrial pyruvate kinase, and CamKII-alpha were affected. Based on the combination of protein set enrichment and bioinformatic pathway analysis, we designed orthogonal SRM-assays which validated the abnormalities of proteins involved in synaptic long-term potentiation, myelination, and the ERK-signalling pathway in both brain regions. In contrast, increased levels of proteins involved in neurotransmitter metabolism and release were found only in the frontal cortex and abnormalities of proteins involved in the purinergic system were found exclusively in the hippocampus. Conclusions Taken together, this multi-platform profiling study has identified peripheral changes which are potentially linked to central alterations in synaptic plasticity and neuronal function associated with NMDAR-NR1 hypofunction. Therefore, the reported proteomic changes may be useful as translational biomarkers in human and rodent model drug discovery efforts.
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Affiliation(s)
- Hendrik Wesseling
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QT, UK
| | - Paul C Guest
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QT, UK
| | - Chi-Ming Lee
- AstraZeneca Pharmaceuticals, 1800 Concord Pike, Wilmington, DE 19850, USA
| | - Erik Hf Wong
- AstraZeneca Pharmaceuticals, 1800 Concord Pike, Wilmington, DE 19850, USA
| | - Hassan Rahmoune
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QT, UK
| | - Sabine Bahn
- Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QT, UK ; Department of Neuroscience, Erasmus Medical Center, Rotterdam, CA, 3000, The Netherlands
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Henshall DC, Diaz-Hernandez M, Miras-Portugal MT, Engel T. P2X receptors as targets for the treatment of status epilepticus. Front Cell Neurosci 2013; 7:237. [PMID: 24324404 PMCID: PMC3840793 DOI: 10.3389/fncel.2013.00237] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 11/08/2013] [Indexed: 11/26/2022] Open
Abstract
Prolonged seizures are amongst the most common neurological emergencies. Status epilepticus is a state of continuous seizures that is life-threatening and prompt termination of status epilepticus is critical to protect the brain from permanent damage. Frontline treatment comprises parenteral administration of anticonvulsants such as lorazepam that facilitate γ-amino butyric acid (GABA) transmission. Because status epilepticus can become refractory to anticonvulsants in a significant proportion of patients, drugs which act on different neurotransmitter systems may represent potential adjunctive treatments. P2X receptors are a class of ligand-gated ion channel activated by ATP that contributes to neuro- and glio-transmission. P2X receptors are expressed by both neurons and glia in various brain regions, including the hippocampus. Electrophysiology, pharmacology and genetic studies suggest certain P2X receptors are activated during pathologic brain activity. Expression of several members of the family including P2X2, P2X4, and P2X7 receptors has been reported to be altered in the hippocampus following status epilepticus. Recent studies have shown that ligands of the P2X7 receptor can have potent effects on seizure severity during status epilepticus and mice lacking this receptor display altered seizures in response to chemoconvulsants. Antagonists of the P2X7 receptor also modulate neuronal death, microglial responses and neuroinflammatory signaling. Recent work also found altered neuronal injury and inflammation after status epilepticus in mice lacking the P2X4 receptor. In summary, members of the P2X receptor family may serve important roles in the pathophysiology of status epilepticus and represent novel targets for seizure control and neuroprotection.
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Affiliation(s)
- David C Henshall
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland Dublin, Ireland ; Centre for the Study of Neurological Disorders, Royal College of Surgeons in Ireland Dublin, Ireland
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Fischer W, Urban N, Immig K, Franke H, Schaefer M. Natural compounds with P2X7 receptor-modulating properties. Purinergic Signal 2013; 10:313-26. [PMID: 24163006 PMCID: PMC4040168 DOI: 10.1007/s11302-013-9392-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/10/2013] [Indexed: 12/19/2022] Open
Abstract
The adenosine 5'-triphosphate (ATP)-gated P2X7 receptor is a membrane-bound, non-selective cation channel, expressed in a variety of cell types. The P2X7 senses high extracellular ATP concentrations and seems to be implicated in a wide range of cellular functions as well as pathophysiological processes, including immune responses and inflammation, release of gliotransmitters and cytokines, cancer cell growth or development of neurodegenerative diseases. In the present study, we identified natural compounds and analogues that can block or sensitize the ATP (1 mM)-induced Ca(2+) response using a HEK293 cell line stably expressing human P2X7 and fluorometric imaging plate reader technology. For instance, teniposide potently blocked the human P2X7 at sub-miromolar concentrations, but not human P2X4 or rat P2X2. A marked block of ATP-induced Ca(2+) entry and Yo-Pro-1 uptake was also observed in human A375 melanoma cells and mouse microglial cells, both expressing P2X7. On the other hand, agelasine (AGL) and garcinolic acid (GA) facilitated the P2X7 response to ATP in all three cell populations. GA also enhanced the YO-PRO-1 uptake, whereas AGL did not affect the ATP-stimulated intracellular accumulation of this dye. According to the pathophysiological role of P2X7 in various diseases, selective modulators may have potential for further development, e.g. as neuroprotective or antineoplastic drugs.
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Affiliation(s)
- Wolfgang Fischer
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, Haertelstr. 16-18, 04107, Leipzig, Germany,
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Waszkielewicz AM, Gunia A, Szkaradek N, Słoczyńska K, Krupińska S, Marona H. Ion channels as drug targets in central nervous system disorders. Curr Med Chem 2013; 20:1241-85. [PMID: 23409712 PMCID: PMC3706965 DOI: 10.2174/0929867311320100005] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 01/14/2013] [Accepted: 01/18/2013] [Indexed: 12/27/2022]
Abstract
Ion channel targeted drugs have always been related with either the central nervous system (CNS), the peripheral nervous system, or the cardiovascular system. Within the CNS, basic indications of drugs are: sleep disorders, anxiety, epilepsy, pain, etc. However, traditional channel blockers have multiple adverse events, mainly due to low specificity of mechanism of action. Lately, novel ion channel subtypes have been discovered, which gives premises to drug discovery process led towards specific channel subtypes. An example is Na(+) channels, whose subtypes 1.3 and 1.7-1.9 are responsible for pain, and 1.1 and 1.2 - for epilepsy. Moreover, new drug candidates have been recognized. This review is focusing on ion channels subtypes, which play a significant role in current drug discovery and development process. The knowledge on channel subtypes has developed rapidly, giving new nomenclatures of ion channels. For example, Ca(2+)s channels are not any more divided to T, L, N, P/Q, and R, but they are described as Ca(v)1.1-Ca(v)3.3, with even newer nomenclature α1A-α1I and α1S. Moreover, new channels such as P2X1-P2X7, as well as TRPA1-TRPV1 have been discovered, giving premises for new types of analgesic drugs.
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Affiliation(s)
- A M Waszkielewicz
- Department of Bioorganic Chemistry, Chair of Organic Chemistry, Faculty of Pharmacy, Jagiellonian University Medical College, 9 Medyczna Street, 30-688 Krakow, Poland.
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Smith SMC, Mitchell GS, Friedle SA, Sibigtroth CM, Vinit S, Watters JJ. Hypoxia Attenuates Purinergic P2X Receptor-Induced Inflammatory Gene Expression in Brainstem Microglia. HYPOXIA 2013; 2013. [PMID: 24377098 PMCID: PMC3873144 DOI: 10.2147/hp.s45529] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hypoxia and increased extracellular nucleotides are frequently coincident in the brainstem. Extracellular nucleotides are potent modulators of microglial inflammatory gene expression via P2X purinergic receptor activation. Although hypoxia is also known to modulate inflammatory gene expression, little is known about how hypoxia or P2X receptor activation alone affects inflammatory molecule production in brainstem microglia, nor how hypoxia and P2X receptor signaling interact when they occur together. In the study reported here, we investigated the ability of a brief episode of hypoxia (2 hours) in the presence and absence of the nonselective P2X receptor agonist 2′(3′)-O-(4-benzoylbenzoyl)adenosine-5′-triphosphate (BzATP) to promote inflammatory gene expression in brainstem microglia in adult rats. We evaluated inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNFα), and interleukin (IL)-6 messenger RNA levels in immunomagnetically isolated brainstem microglia. While iNOS and IL-6 gene expression increased with hypoxia and BzATP alone, TNFα expression was unaffected. Surprisingly, BzATP-induced inflammatory effects were lost after hypoxia, suggesting that hypoxia impairs proinflammatory P2X-receptor signaling. We also evaluated the expression of key P2X receptors activated by BzATP, namely P2X1, P2X4, and P2X7. While hypoxia did not alter their expression, BzATP upregulated P2X4 and P2X7 mRNAs; these effects were ablated in hypoxia. Although both P2X4 and P2X7 receptor expression correlated with increased microglial iNOS and IL-6 levels in microglia from normoxic rats, in hypoxia, P2X7 only correlated with IL-6, and P2X4 correlated only with iNOS. In addition, correlations between P2X7 and P2X4 were lost following hypoxia, suggesting that P2X4 and P2X7 receptor signaling differs in normoxia and hypoxia. Together, these data suggest that hypoxia suppresses P2X receptor-induced inflammatory gene expression, indicating a potentially immunosuppressive role of extracellular nucleotides in brainstem microglia following exposure to hypoxia.
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Affiliation(s)
- Stephanie M C Smith
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA 53706 ; Comparative Biomedical Sciences Training Program, University of Wisconsin, Madison, WI, USA 53706
| | - Gordon S Mitchell
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA 53706 ; Comparative Biomedical Sciences Training Program, University of Wisconsin, Madison, WI, USA 53706
| | - Scott A Friedle
- Program in Cellular and Molecular Biology, University of Wisconsin, Madison, WI, USA 53706
| | | | - Stéphane Vinit
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA 53706
| | - Jyoti J Watters
- Department of Comparative Biosciences, University of Wisconsin, Madison, WI, USA 53706 ; Comparative Biomedical Sciences Training Program, University of Wisconsin, Madison, WI, USA 53706 ; Program in Cellular and Molecular Biology, University of Wisconsin, Madison, WI, USA 53706
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Block of P2X7 receptors could partly reverse the delayed neuronal death in area CA1 of the hippocampus after transient global cerebral ischemia. Purinergic Signal 2013; 9:663-75. [PMID: 23877788 DOI: 10.1007/s11302-013-9379-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 07/02/2013] [Indexed: 12/21/2022] Open
Abstract
Transient global ischemia (which closely resembles clinical situations such as cardiac arrest, near drowning or severe systemic hypotension during surgical procedures), often induces delayed neuronal death in the brain, especially in the hippocampal CA1 region. The mechanism of ischemia/reperfusion (I/R) injury is not fully understood. In this study, we have shown that the P2X7 receptor antagonist, BBG, reduced delayed neuronal death in the hippocampal CA1 region after I/R injury; P2X7 receptor expression levels increased before delayed neuronal death after I/R injury; inhibition of the P2X7 receptor reduced I/R-induced microglial microvesicle-like components, IL-1β expression, P38 phosphorylation, and glial activation in hippocampal CA1 region after I/R injury. These results indicate that antagonism of the P2X7 receptor and signaling pathways of microglial MV shedding, such as src-protein tyrosine kinase, P38 MAP kinase and A-SMase, might be a promising therapeutic strategy for clinical treatment of transient global cerebral I/R injury.
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P2X7 receptor activation regulates microglial cell death during oxygen-glucose deprivation. Neuropharmacology 2013; 73:311-9. [PMID: 23770338 DOI: 10.1016/j.neuropharm.2013.05.032] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 05/21/2013] [Accepted: 05/23/2013] [Indexed: 12/28/2022]
Abstract
Brain-resident microglia may promote tissue repair following stroke but, like other cells, they are vulnerable to ischemia. Here we identify mechanisms involved in microglial ischemic vulnerability. Using time-lapse imaging of cultured BV2 microglia, we show that simulated ischemia (oxygen-glucose deprivation; OGD) induces BV2 microglial cell death. Removal of extracellular Ca(2+) or application of Brilliant Blue G (BBG), a potent P2X7 receptor (P2X7R) antagonist, protected BV2 microglia from death. To validate and extend these in vitro findings, we assessed parenchymal microglia in freshly isolated hippocampal tissue slices from GFP-reporter mice (CX3CR1(GFP/+)). We confirmed that calcium removal or application of apyrase, an ATP-degrading enzyme, abolished OGD-induced microglial cell death in situ, consistent with involvement of ionotropic purinergic receptors. Indeed, whole cell recordings identified P2X7R-like currents in tissue microglia, and OGD-induced microglial cell death was inhibited by BBG. These pharmacological results were complemented by studies in tissue slices from P2X7R null mice, in which OGD-induced microglia cell death was reduced by nearly half. Together, these results indicate that stroke-like conditions induce calcium-dependent microglial cell death that is mediated in part by P2X7R. This is the first identification of a purinergic receptor regulating microglial survival in living brain tissues. From a therapeutic standpoint, these findings could help direct novel approaches to enhance microglial survival and function following stroke and other neuropathological conditions.
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Bai HY, Li AP. P2X(7) receptors in cerebral ischemia. Neurosci Bull 2013; 29:390-8. [PMID: 23640286 DOI: 10.1007/s12264-013-1338-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 10/16/2012] [Indexed: 12/25/2022] Open
Abstract
Cerebral ischemia is one of the most common diseases resulting in death and disability in aged people. It leads immediately to rapid energy failure, ATP depletion, and ionic imbalance, which increase extracellular ATP levels and accordingly activate P2X7 receptors. These receptors are ATP-gated cation channels and widely distributed in nerve cells, especially in the immunocompetent cells of the brain. Currently, interest in the roles of P2X7 receptors in ischemic brain injury is growing. In this review, we discuss recent research progress on the actions of P2X7 receptors, their possible mechanisms in cerebral ischemia, and the potential therapeutic value of P2X7 receptor antagonists which may provide a new target both for clinical and for research purposes.
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Affiliation(s)
- Hui-Yu Bai
- Department of Physiology, Dalian Medical University, Dalian, 116044, China
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Domercq M, Vázquez-Villoldo N, Matute C. Neurotransmitter signaling in the pathophysiology of microglia. Front Cell Neurosci 2013; 7:49. [PMID: 23626522 PMCID: PMC3630369 DOI: 10.3389/fncel.2013.00049] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 04/05/2013] [Indexed: 01/09/2023] Open
Abstract
Microglial cells are the resident immune cells of the central nervous system. In the resting state, microglia are highly dynamic and control the environment by rapidly extending and retracting motile processes. Microglia are closely associated with astrocytes and neurons, particularly at the synapses, and more recent data indicate that neurotransmission plays a role in regulating the morphology and function of surveying/resting microglia, as they are endowed with receptors for most known neurotransmitters. In particular, microglia express receptors for ATP and glutamate, which regulate microglial motility. After local damage, the release of ATP induces microgliosis and activated microglial cells migrate to the site of injury, proliferate, and phagocytose cells, and cellular compartments. However, excessive activation of microglia could contribute to the progression of chronic neurodegenerative diseases, though the underlying mechanisms are still unclear. Microglia have the capacity to release a large number of substances that can be detrimental to the surrounding neurons, including glutamate, ATP, and reactive oxygen species. However, how altered neurotransmission following acute insults or chronic neurodegenerative conditions modulates microglial functions is still poorly understood. This review summarizes the relevant data regarding the role of neurotransmitter receptors in microglial physiology and pathology.
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Affiliation(s)
- María Domercq
- Departamento de Neurociencias, Universidad del País Vasco-UPV/EHU Leioa, Spain ; Achucarro Basque Center for Neuroscience-UPV/EHU Zamudio, Spain ; Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas Leioa, Spain
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Weilinger NL, Maslieieva V, Bialecki J, Sridharan SS, Tang PL, Thompson RJ. Ionotropic receptors and ion channels in ischemic neuronal death and dysfunction. Acta Pharmacol Sin 2013; 34:39-48. [PMID: 22864302 DOI: 10.1038/aps.2012.95] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Loss of energy supply to neurons during stroke induces a rapid loss of membrane potential that is called the anoxic depolarization. Anoxic depolarizations result in tremendous physiological stress on the neurons because of the dysregulation of ionic fluxes and the loss of ATP to drive ion pumps that maintain electrochemical gradients. In this review, we present an overview of some of the ionotropic receptors and ion channels that are thought to contribute to the anoxic depolarization of neurons and subsequently, to cell death. The ionotropic receptors for glutamate and ATP that function as ligand-gated cation channels are critical in the death and dysfunction of neurons. Interestingly, two of these receptors (P2X7 and NMDAR) have been shown to couple to the pannexin-1 (Panx1) ion channel. We also discuss the important roles of transient receptor potential (TRP) channels and acid-sensing ion channels (ASICs) in responses to ischemia. The central challenge that emerges from our current understanding of the anoxic depolarization is the need to elucidate the mechanistic and temporal interrelations of these ion channels to fully appreciate their impact on neurons during stroke.
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Chu K, Yin B, Wang J, Peng G, Liang H, Xu Z, Du Y, Fang M, Xia Q, Luo B. Inhibition of P2X7 receptor ameliorates transient global cerebral ischemia/reperfusion injury via modulating inflammatory responses in the rat hippocampus. J Neuroinflammation 2012; 9:69. [PMID: 22513224 PMCID: PMC3418181 DOI: 10.1186/1742-2094-9-69] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Accepted: 04/18/2012] [Indexed: 01/05/2023] Open
Abstract
Background Neuroinflammation plays an important role in cerebral ischemia/reperfusion (I/R) injury. The P2X7 receptor (P2X7R) has been reported to be involved in the inflammatory response of many central nervous system diseases. However, the role of P2X7Rs in transient global cerebral I/R injury remains unclear. The purpose of this study is to determine the effects of inhibiting the P2X7R in a rat model of transient global cerebral I/R injury, and then to explore the association between the P2X7R and neuroinflammation after transient global cerebral I/R injury. Methods Immediately after infusion with the P2X7R antagonists Brilliant blue G (BBG), adenosine 5′-triphosphate-2′,3′-dialdehyde (OxATP) or A-438079, 20 minutes of transient global cerebral I/R was induced using the four-vessel occlusion (4-VO) method in rats. Survival rate was calculated, neuronal death in the hippocampal CA1 region was observed using H & E staining, and DNA cleavage was observed by deoxynucleotidyl transferase-mediated UTP nick end labeling TUNEL). In addition, behavioral deficits were measured using the Morris water maze, and RT-PCR and immunohistochemical staining were performed to measure the expression of IL-1β, TNF-α and IL-6, and to identify activated microglia and astrocytes. Results The P2X7R antagonists protected against transient global cerebral I/R injury in a dosage-dependent manner. A high dosage of BBG (10 μg) and A-0438079 (3 μg), and a low dosage of OxATP (1 μg) significantly increased survival rates, reduced I/R-induced learning memory deficit, and reduced I/R-induced neuronal death, DNA cleavage, and glial activation and inflammatory cytokine overexpression in the hippocampus. Conclusions Our study indicates that inhibiting P2X7Rs protects against transient global cerebral I/R injury by reducing the I/R-induced inflammatory response, which suggests inhibition of P2X7Rs may be a promising therapeutic strategy for clinical treatment of transient global cerebral I/R injury.
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Affiliation(s)
- Ketan Chu
- Department of Neurology, First Affiliated Hospital, Zhejiang University School of Medicine, 76 Qingchun Road, Hangzhou 310003, China
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Engel T, Gomez-Villafuertes R, Tanaka K, Mesuret G, Sanz-Rodriguez A, Garcia-Huerta P, Miras-Portugal MT, Henshall DC, Diaz-Hernandez M. Seizure suppression and neuroprotection by targeting the purinergic P2X7 receptor during status epilepticus in mice. FASEB J 2011; 26:1616-28. [PMID: 22198387 DOI: 10.1096/fj.11-196089] [Citation(s) in RCA: 151] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Prolonged seizures [status epilepticus (SE)] constitute a neurological emergency that can permanently damage the brain. SE results from a failure of the normal mechanisms to terminate seizures; in particular, γ-amino butyric acid-mediated inhibition, and benzodiazepine anticonvulsants are often incompletely effective. ATP acts as a fast neurotransmitter via ionotropic ligand-gated P2X receptors. Here we report that SE induced by intra-amygdala kainic acid in mice selectively increased hippocampal levels of P2X7 receptors relative to other P2X receptors. Using transgenic P2X7 reporter mice expressing enhanced green fluorescent protein, we identify dentate granule neurons as the major cell population transcribing the P2X7 receptor after SE. Pretreatment of mice with an intracerebroventricular microinjection of 1.75 nmol A438079, a P2X7 receptor antagonist, reduced seizure duration by 58% and reduced seizure-induced neuronal death by 61%. Injection of brilliant blue G (1 pmol), another selective antagonist, reduced seizure duration by 48% and was also neuroprotective. A438079 was seizure-suppressive when injected shortly after induction of SE, and coinjection of A438079 with lorazepam 60 min after triggering SE, when electrographic seizure-responsiveness to lorazepam had decreased, also terminated SE. Our results suggest that P2X7 receptor antagonists may be a promising class of drug for seizure abrogation and neuroprotection in SE.
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Affiliation(s)
- Tobias Engel
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland
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A reassessment of P2X7 receptor inhibition as a neuroprotective strategy in rat models of contusion injury. Exp Neurol 2011; 233:687-92. [PMID: 22078760 DOI: 10.1016/j.expneurol.2011.06.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 06/08/2011] [Accepted: 06/18/2011] [Indexed: 02/07/2023]
Abstract
These experiments were completed as part of an NIH "Facilities of Research Excellence in Spinal Cord Injury" contract to support independent replication of published studies that could be considered for eventual clinical testing. Recent studies have reported that selective inhibition of the P2X7 receptor improves both the functional and histopathological consequences of a contusive spinal cord injury (SCI) in rats. We repeated two published studies reporting the beneficial effects of pyridoxal-5'-phosphate-6-azophenyl-2'-4'-disulphonic acid (PPADS) or Brilliant blue G (BBG) treatment after SCI (Wang et al., 2004 and Peng et al., 2009). Mild thoracic SCI was first produced in Experiment 1 by means of the MASCIS impactor at T10 (height 6.25 mm, weight 10 g) followed by intraspinal administration of a P2X7 antagonist (2 μl/10 mM) after injury. Treatment with PPADS or another highly selective P2X7R antagonist Brilliant Blue G (BBG) (2 μl/02 mM) did not improve locomotive (BBB rating scale) over a 7 week period compared to vehicle treated rats. Also, secondary histopathological changes in terms of overall lesion and cavity volume were not significantly different between the PPADS, BBG, and vehicle treated animals. In the second experiment, the systemic administration of BBG (10 or 50 mg/kg, iv) 15 min, 24 and 72 h after moderate (12.5 mm) SCI failed to significantly improve motor recovery or histopathological outcome over the 6 week observational period. Although we cannot conclude that there will be no long-term beneficial effects in other spinal cord injury models using selective P2X7 receptor antagonists at different doses or treatment durations, we caution researchers that this potentially exciting therapy requires further preclinical investigations before the implementation of clinical trials targeting severe SCI patients.
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The roles of P2X7 receptor in regional-specific microglial responses in the rat brain following status epilepticus. Neurol Sci 2011; 33:515-25. [PMID: 21845474 DOI: 10.1007/s10072-011-0740-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 07/26/2011] [Indexed: 10/17/2022]
Abstract
Recently, we have reported that astroglial activations in response to status epilepticus (SE) show regional-specific manners in the rat hippocampus. However, it is unknown that microglial responses to SE would show regional-specific patterns. Therefore, the present study was designed to elucidate the regional-specific microglial activation and relationship between P2X7 receptor functions and SE-induced microglial responses in the rat brain. Following SE, microglia appeared amoeboid or phagocytic in the dentate gyrus and the piriform cortex. In contrast, elongated microglia were observed in the CA1 hippocampal regions and the frontoparietal cortex. In the dentate gyrus, the CA1 hippocampal regions, and the frontoparietal cortex, these microglial activation accelerated by BzATP (a P2X7 receptor agonist)-infusion, but inhibited by OxATP (a P2X7 receptor antagonist). However, SE-induced microglial activation in the piriform cortex was not affected by BzATP or OxATP-infusion. Therefore, our findings indicate that SE-induced microglial activation may show regional-specific manners, and suggest that P2X7 receptor function differently modulates SE-induced microglial responses in distinct brain regions.
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Lämmer AB, Beck A, Grummich B, Förschler A, Krügel T, Kahn T, Schneider D, Illes P, Franke H, Krügel U. The P2 receptor antagonist PPADS supports recovery from experimental stroke in vivo. PLoS One 2011; 6:e19983. [PMID: 21611146 PMCID: PMC3096654 DOI: 10.1371/journal.pone.0019983] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 04/21/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND After ischemia of the CNS, extracellular adenosine 5'-triphosphate (ATP) can reach high concentrations due to cell damage and subsequent increase of membrane permeability. ATP may cause cellular degeneration and death, mediated by P2X and P2Y receptors. METHODOLOGY/PRINCIPAL FINDINGS The effects of inhibition of P2 receptors by pyridoxalphosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) on electrophysiological, functional and morphological alterations in an ischemia model with permanent middle cerebral artery occlusion (MCAO) were investigated up to day 28. Spontaneously hypertensive rats received PPADS or vehicle intracerebroventricularly 15 minutes prior MCAO for up to 7 days. The functional recovery monitored by qEEG was improved by PPADS indicated by an accelerated recovery of ischemia-induced qEEG changes in the delta and alpha frequency bands along with a faster and sustained recovery of motor impairments. Whereas the functional improvements by PPADS were persistent at day 28, the infarct volume measured by magnetic resonance imaging and the amount of TUNEL-positive cells were significantly reduced by PPADS only until day 7. Further, by immunohistochemistry and confocal laser scanning microscopy, we identified both neurons and astrocytes as TUNEL-positive after MCAO. CONCLUSION The persistent beneficial effect of PPADS on the functional parameters without differences in the late (day 28) infarct size and apoptosis suggests that the early inhibition of P2 receptors might be favourable for the maintenance or early reconstruction of neuronal connectivity in the periinfarct area after ischemic incidents.
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Affiliation(s)
- Alexandra B. Lämmer
- Department of Neurology,
Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen,
Germany
- Department of Neurology, University of
Leipzig, Leipzig, Germany
| | - Alexander Beck
- Department of Neurology,
Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen,
Germany
| | - Benjamin Grummich
- Rudolf-Boehm-Institute of Pharmacology and
Toxicology, University of Leipzig, Leipzig, Germany
| | - Annette Förschler
- Department of Diagnostic and Interventional
Radiology, University of Leipzig, Leipzig, Germany
| | - Thomas Krügel
- Rudolf-Boehm-Institute of Pharmacology and
Toxicology, University of Leipzig, Leipzig, Germany
| | - Thomas Kahn
- Department of Diagnostic and Interventional
Radiology, University of Leipzig, Leipzig, Germany
| | | | - Peter Illes
- Rudolf-Boehm-Institute of Pharmacology and
Toxicology, University of Leipzig, Leipzig, Germany
| | - Heike Franke
- Rudolf-Boehm-Institute of Pharmacology and
Toxicology, University of Leipzig, Leipzig, Germany
| | - Ute Krügel
- Rudolf-Boehm-Institute of Pharmacology and
Toxicology, University of Leipzig, Leipzig, Germany
- * E-mail:
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Hracskó Z, Baranyi M, Csölle C, Gölöncsér F, Madarász E, Kittel A, Sperlágh B. Lack of neuroprotection in the absence of P2X7 receptors in toxin-induced animal models of Parkinson's disease. Mol Neurodegener 2011; 6:28. [PMID: 21542899 PMCID: PMC3113297 DOI: 10.1186/1750-1326-6-28] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Accepted: 05/04/2011] [Indexed: 01/06/2023] Open
Abstract
Background Previous studies indicate a role of P2X7 receptors in processes that lead to neuronal death. The main objective of our study was to examine whether genetic deletion or pharmacological blockade of P2X7 receptors influenced dopaminergic cell death in various models of Parkinson's disease (PD). Results mRNA encoding P2X7 and P2X4 receptors was up-regulated after treatment of PC12 cells with 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP). P2X7 antagonists protected against MPTP and rotenone induced toxicity in the LDH assay, but failed to protect after rotenone treatment in the MTT assay in PC12 cells and in primary midbrain culture. In vivo MPTP and in vitro rotenone pretreatments increased the mRNA expression of P2X7 receptors in the striatum and substantia nigra of wild-type mice. Basal mRNA expression of P2X4 receptors was higher in P2X7 knockout mice and was further up-regulated by MPTP treatment. Genetic deletion or pharmacological inhibition of P2X7 receptors did not change survival rate or depletion of striatal endogenous dopamine (DA) content after in vivo MPTP or in vitro rotenone treatment. However, depletion of norepinephrine was significant after MPTP treatment only in P2X7 knockout mice. The basal ATP content was higher in the substantia nigra of wild-type mice, but the ADP level was lower. Rotenone treatment elicited a similar reduction in ATP content in the substantia nigra of both genotypes, whereas reduction of ATP was more pronounced after rotenone treatment in striatal slices of P2X7 deficient mice. Although the endogenous amino acid content remained unchanged, the level of the endocannabinoid, 2-AG, was elevated by rotenone in the striatum of wild-type mice, an effect that was absent in mice deficient in P2X7 receptors. Conclusions We conclude that P2X7 receptor deficiency or inhibition does not support the survival of dopaminergic neurons in an in vivo or in vitro models of PD.
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Affiliation(s)
- Zsuzsanna Hracskó
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, H-1083 Budapest, Szigony u, 43, Hungary.
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Orellana JA, Froger N, Ezan P, Jiang JX, Bennett MVL, Naus CC, Giaume C, Sáez JC. ATP and glutamate released via astroglial connexin 43 hemichannels mediate neuronal death through activation of pannexin 1 hemichannels. J Neurochem 2011; 118:826-40. [PMID: 21294731 DOI: 10.1111/j.1471-4159.2011.07210.x] [Citation(s) in RCA: 285] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Inflammation contributes to neurodegeneration in post-ischemic brain, diabetes, and Alzheimer's disease. Participants in this inflammatory response include activation of microglia and astrocytes. We studied the role of microglia treated with amyloid-β peptide (Aβ) on hemichannel activity of astrocytes subjected to hypoxia in high glucose. Reoxygenation after 3 h hypoxia in high glucose induced transient astroglial permeabilization via Cx43 hemichannels and reduction in intercellular communication via Cx43 cell-cell channels. Both responses were greater and longer lasting in astrocytes previously exposed for 24 h to conditioned medium from Aβ-treated microglia (CM-Aβ). The effects of CM-Aβ were mimicked by TNF-α and IL-1β and were abrogated by neutralizing TNF-α with soluble receptor and IL-1β with a receptor antagonist. Astrocytes under basal conditions protected neurons against hypoxia, but exposure to CM-Aβ made them toxic to neurons subjected to a sub-lethal hypoxia/reoxygenation episode, revealing the additive nature of the insults. Astrocytes exposed to CM-Aβ induced permeabilization of cortical neurons through activation of neuronal pannexin 1 (Panx1) hemichannels by ATP and glutamate released through astroglial Cx43 hemichannels. In agreement, inhibition of NMDA or P2X receptors only partially reduced the activation of neuronal Panx1 hemichannels and neuronal mortality, but simultaneous inhibition of both receptors completely prevented the neurotoxic response. Therefore, we suggest that responses to ATP and glutamate converge in activation of neuronal Panx1 hemichannels. Thus, we propose that blocking hemichannels expressed by astrocytes and/or neurons in the inflamed nervous system could represent a novel and alternative strategy to reduce neuronal loss in various pathological states including Alzheimer's disease, diabetes and ischemia.
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Affiliation(s)
- Juan A Orellana
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile.
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Woodfin A, Hu DE, Sarker M, Kurokawa T, Fraser P. Acute NADPH oxidase activation potentiates cerebrovascular permeability response to bradykinin in ischemia-reperfusion. Free Radic Biol Med 2011; 50:518-24. [PMID: 21167936 PMCID: PMC3038265 DOI: 10.1016/j.freeradbiomed.2010.12.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 11/12/2010] [Accepted: 12/08/2010] [Indexed: 12/02/2022]
Abstract
Free radical generation is a key event in cerebral reperfusion injury. Bradykinin (Bk) and interleukin-1β (IL-1β) have both been implicated in edema formation after stroke, although acute Bk application itself results in only a modest permeability increase. We have investigated the molecular mechanism by assessing the permeability of single pial venules in a stroke model. Increased permeability on reperfusion was dependent on the duration of ischemia and was prevented by applying the B(2) receptor antagonist HOE 140. Postreperfusion permeability increases were mimicked by applying Bk (5μM) for 10 min and blocked by coapplying the IL-1 receptor antagonist with Bk. Furthermore, 10 min pretreatment with IL-1β resulted in a 3 orders of magnitude leftward shift of the acutely applied Bk concentration-response curve. The left shift was abolished by scavenging free radicals with superoxide dismutase and catalase. Apocynin coapplied with IL-1β completely blocked the potentiation, implying that NADPH oxidase assembly is the immediate target of IL-1β. In conclusion, this is first demonstration that bradykinin, released during cerebral ischemia, leads to IL-1β release, which in turn activates NADPH oxidase leading to blood-brain barrier breakdown.
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Abstract
Excessive signalling by excitatory neurotransmitters like glutamate and ATP can be deleterious to neurons and oligodendroglia, and cause disease. In particular, sustained activation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), kainate and N-methyl-d-aspartate (NMDA) receptors damages oligodendrocytes, a feature that depends entirely on Ca(2+) overload of the cytoplasm and that can be initiated by disruption of glutamate homeostasis. Thus, inhibition of glutamate uptake by activated microglia can compromise glutamate homeostasis and induce oligodendrocyte excitotoxicity. Moreover, non-lethal, brief activation of kainate receptors in oligodendrocytes rapidly sensitizes these cells to complement attack as a consequence of oxidative stress. In addition to glutamate, ATP signalling can directly trigger oligodendrocyte excitotoxicity via activation of Ca(2+) -permeable P2X7 purinergic receptors, which mediates ischaemic damage to white matter (WM) and causes lesions that are reminiscent of multiple sclerosis (MS) plaques. Conversely, blockade of P2X7 receptors attenuates post-ischaemic injury to WM and ameliorates chronic experimental autoimmune encephalomyelitis, a model of MS. Importantly, P2X7 expression is elevated in normal-appearing WM in patients with MS, suggesting that signalling through this receptor in oligodendrocytes may be enhanced in this disease. Altogether, these observations reveal novel mechanisms by which altered glutamate and ATP homeostasis can trigger oligodendrocyte death. This review aims at summarizing current knowledge about the mechanisms leading to WM damage as a consequence of altered neurotransmitter signalling, and their relevance to disease. This knowledge will generate new therapeutic avenues to treat more efficiently acute and chronic WM pathology.
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Affiliation(s)
- Carlos Matute
- Departamento de Neurociencias and CIBERNED, Universidad del País Vasco, Leioa, Vizcaya, Spain Neurotek-UPV/EHU, Parque Tecnológico de Bizkaia, Zamudio, Spain.
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Köles L, Leichsenring A, Rubini P, Illes P. P2 receptor signaling in neurons and glial cells of the central nervous system. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2011; 61:441-93. [PMID: 21586367 DOI: 10.1016/b978-0-12-385526-8.00014-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Purine and pyrimidine nucleotides are extracellular signaling molecules in the central nervous system (CNS) leaving the intracellular space of various CNS cell types via nonexocytotic mechanisms. In addition, ATP is a neuro-and gliotransmitter released by exocytosis from neurons and neuroglia. These nucleotides activate P2 receptors of the P2X (ligand-gated cationic channels) and P2Y (G protein-coupled receptors) types. In mammalians, seven P2X and eight P2Y receptor subunits occur; three P2X subtypes form homomeric or heteromeric P2X receptors. P2Y subtypes may also hetero-oligomerize with each other as well as with other G protein-coupled receptors. P2X receptors are able to physically associate with various types of ligand-gated ion channels and thereby to interact with them. The P2 receptor homomers or heteromers exhibit specific sensitivities against pharmacological ligands and have preferential functional roles. They may be situated at both presynaptic (nerve terminals) and postsynaptic (somatodendritic) sites of neurons, where they modulate either transmitter release or the postsynaptic sensitivity to neurotransmitters. P2 receptors exist at neuroglia (e.g., astrocytes, oligodendrocytes) and microglia in the CNS. The neuroglial P2 receptors subserve the neuron-glia cross talk especially via their end-feets projecting to neighboring synapses. In addition, glial networks are able to communicate through coordinated oscillations of their intracellular Ca(2+) over considerable distances. P2 receptors are involved in the physiological regulation of CNS functions as well as in its pathophysiological dysregulation. Normal (motivation, reward, embryonic and postnatal development, neuroregeneration) and abnormal regulatory mechanisms (pain, neuroinflammation, neurodegeneration, epilepsy) are important examples for the significance of P2 receptor-mediated/modulated processes.
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Affiliation(s)
- Laszlo Köles
- Rudolph-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, Germany
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Kim JE, Ryu HJ, Yeo SI, Kang TC. P2X7 receptor regulates leukocyte infiltrations in rat frontoparietal cortex following status epilepticus. J Neuroinflammation 2010; 7:65. [PMID: 20939924 PMCID: PMC2964655 DOI: 10.1186/1742-2094-7-65] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2010] [Accepted: 10/12/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND In the present study, we investigated the roles of P2X7 receptor in recruitment and infiltration of neutrophil during epileptogenesis in rat epilepsy models. METHODS Status epilepticus (SE) was induced by pilocarpine in rats that were intracerebroventricularly infused with either saline, 2',3'-O-(4-benzoylbenzoyl)-adenosine 5'-triphosphate (BzATP), adenosine 5'-triphosphate-2',3'-dialdehyde (OxATP), or IL-1Ra (interleukin 1 receptor antagonist) prior to SE induction. Thereafter, we performed immunohistochemical studies for myeloperoxidase (MPO), CD68, interleukin-1β (IL-1β), monocyte chemotactic protein-1 (MCP-1) and macrophage inflammatory protein-2 (MIP-2). RESULTS In saline-infused animals, neutrophils and monocytes were observed in frontoparietal cortex (FPC) at 1 day and 2 days after SE, respectively. In BzATP-infused animals, infiltrations of neutrophils and monocytes into the FPC were detected at 12 hr and 1 day after SE, respectively. In OxATP-infused animals, neutrophils and monocytes infiltrated into the FPC at 1 day and 2 days after SE, respectively. However, the numbers of both classes of leukocytes were significantly lower than those observed in the saline-infused group. In piriform cortex (PC), massive leukocyte infiltration was detected in layers III/IV of saline-infused animals at 1-4 days after induction of SE. BzATP or OxATP infusion did not affect neutrophil infiltration in the PC. In addition, P2X7 receptor-mediated MCP-1 (released from microglia)/MIP-2 (released from astrocytes) regulation was related to SE-induced leukocyte infiltration in an IL-1β-independent manner. CONCLUSIONS Our findings suggest that selective regulation of P2X7 receptor-mediated neutrophil infiltration may provide new therapeutic approaches to SE or epilepsy.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chunchon 200-702, South Korea
| | - Hea Jin Ryu
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chunchon 200-702, South Korea
| | - Seong-Il Yeo
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chunchon 200-702, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chunchon 200-702, South Korea
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Tamajusuku ASK, Villodre ES, Paulus R, Coutinho-Silva R, Battasstini AMO, Wink MR, Lenz G. Characterization of ATP-induced cell death in the GL261 mouse glioma. J Cell Biochem 2010; 109:983-91. [PMID: 20069573 DOI: 10.1002/jcb.22478] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Gliomas have one of the worst prognosis among cancers. Their resistance to cell death induced by endogenous neurotoxic agents, such as extracellular ATP, seems to play an important role in their pathobiology since alterations in the degradation rate of extracellular ATP drastically affects glioma growth in rats. In the present work we characterized the mechanisms of cell death induced by extracellular ATP in a murine glioma cell line, GL261. ATP and BzATP, a P2X7 agonist, induced cell death at concentrations that are described to activate the P2X7 receptor in mouse. oATP, an antagonist of P2X7, blocked the ATP-induced cell death. Agonists of purinergic receptors expressed in GL261 such as adenosine, ADP, UTP did not cause any cell death, even at mM concentrations. A sub-population of cells more sensitive to ATP expressed more P2X7 when compared to a less sensitive subpopulation. Accordingly, RNA interference of the P2X7 receptor drastically reduced ATP-induced cell death, suggesting that this receptor is necessary for this effect. The mechanism of ATP-induced cell death is predominantly necrotic, since cells presented shrinkage accompanied by membrane permeabilization, but not apoptotic, since no phosphatidylserine externalization or caspase activity was observed. These data show the importance of P2X7 in ATP-induced cell death and shed light on the importance of ATP-induced cell death in glioma development.
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Shiratori M, Tozaki-Saitoh H, Yoshitake M, Tsuda M, Inoue K. P2X7 receptor activation induces CXCL2 production in microglia through NFAT and PKC/MAPK pathways. J Neurochem 2010; 114:810-9. [PMID: 20477948 DOI: 10.1111/j.1471-4159.2010.06809.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microglia plays an important role in many neurodegenerative conditions. ATP leaked or released by damaged cells triggers microglial activation through P2 receptors, and stimulates the release of oxygen radicals, proinflammatory cytokines and chemokines from activated microglia. However, little is known about mechanisms underlying ATP-induced chemokine release from microglia. In this study, we found that a high concentration of ATP induces the mRNA expression and release of CXCL2 from microglia. A similar effect was observed following treatment of microglia with a P2X7 receptor (P2X7R) agonist, 2'-and 3'-O-(4-benzoylbenzoyl) ATP, and this was inhibited by pre-treatment with a P2X7R antagonist, Brilliant Blue G. ATP induced both activation of nuclear factor of activated T cells (NFAT) and MAPKs (p38, ERK, and JNK) through P2X7R. ATP-induced mRNA expression of CXCL2 was inhibited by INCA-6 (an NFAT inhibitor), SB203580 (a p38 inhibitor), U0126 (a MEK-ERK inhibitor) and JNK inhibitor II (a JNK inhibitor). However, MAPK inhibitors did not inhibit activation of NFAT. In addition, protein kinase C inhibitors suppressed ATP-induced ERK and JNK activation, and also inhibited ATP-induced CXCL2 expression in microglia. These results suggest that ATP increased CXCL2 production via both NFAT and protein kinase C/MAPK signaling pathways through P2X7 receptor stimulation in microglia.
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Affiliation(s)
- Miho Shiratori
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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Arai K, Lo EH. Experimental models for analysis of oligodendrocyte pathophysiology in stroke. EXPERIMENTAL & TRANSLATIONAL STROKE MEDICINE 2009; 1:6. [PMID: 20150984 PMCID: PMC2820444 DOI: 10.1186/2040-7378-1-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 10/24/2009] [Indexed: 02/06/2023]
Abstract
White matter damage is a clinically important part of stroke. However, compared to the mechanisms of neuronal injury in gray matter, white matter pathophysiology remains relatively understudied and poorly understood. This mini-review aims at summarizing current knowledge on experimental systems for analyzing the role of white matter injury relevant to stroke. In vitro platforms comprise primary cultures of both mature oligodendrocytes (OLGs) as well as oligodendrocyte precursor cells (OPCs). Tissue platforms involve preparations of optic nerve systems. Whole-animal platforms comprise in vivo models of cerebral ischemia that attempt to target white matter brain areas. While there is no single perfect model system, the collection of these experimental approaches have recently allowed a better understanding of the molecular and cellular pathways underlying OLG/OPC damage and demyelination. A systematic utilization of these cell, tissue and whole-animal platforms may eventually lead us to discover new targets for treating white matter injury in stroke and other CNS disorders.
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Affiliation(s)
- Ken Arai
- Neuroprotection Research Laboratory, Massachusetts General Hospital, Harvard Medical School, Charlestown, USA.
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