101
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Ma C, Zhu Z, Wang X, Zhao G, Liu X, Li R. Vasopressin decreases neuronal apoptosis during cardiopulmonary resuscitation. Neural Regen Res 2014; 9:622-9. [PMID: 25206865 PMCID: PMC4146244 DOI: 10.4103/1673-5374.130107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/10/2014] [Indexed: 11/04/2022] Open
Abstract
The American Heart Association and the European Resuscitation Council recently recommended that vasopressin can be used for cardiopulmonary resuscitation, instead of epinephrine. However, the guidelines do not discuss the effects of vasopressin during cerebral resuscitation. In this study, we intraperitoneally injected epinephrine and/or vasopressin during cardiopulmonary resuscitation in a rat model of asphyxial cardiac arrest. The results demonstrated that, compared with epinephrine alone, the pathological damage to nerve cells was lessened, and the levels of c-Jun N-terminal kinase and p38 expression were significantly decreased in the hippocampus after treatment with vasopressin alone or the vasopressin and epinephrine combination. No significant difference in resuscitation effects was detected between vasopressin alone and the vasopressin and epinephrine combination. These results suggest that vasopressin alone or the vasopressin and epinephrine combination suppress the activation of mitogen-activated protein kinase and c-Jun N-terminal kinase signaling pathways and reduce neuronal apoptosis during cardiopulmonary resuscitation.
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Affiliation(s)
- Chi Ma
- Department of Neurosurgery, the First Hospital, Jilin University, Changchun, Jilin Province, China
| | - Zhe Zhu
- Center for Hand and Foot Surgery and Reparative and Reconstructive Surgery, Orthopedics Hospital, the Second Hospital, Jilin University, Changchun, Jilin Province, China
| | - Xu Wang
- Department of Neurology, the First Hospital, Jilin University, Changchun, Jilin Province, China
| | - Gang Zhao
- Department of Neurosurgery, the First Hospital, Jilin University, Changchun, Jilin Province, China
| | - Xiaoliang Liu
- Emergency Medicine, the First Hospital, Jilin University, Changchun, Jilin Province, China
| | - Rui Li
- Center for Hand and Foot Surgery and Reparative and Reconstructive Surgery, Orthopedics Hospital, the Second Hospital, Jilin University, Changchun, Jilin Province, China
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102
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Shin DB, Han EH, Park SS. Cytoprotective Effects of Phaeophyta Extracts from the Coast of Jeju Island in HT-22 Mouse Neuronal Cells. ACTA ACUST UNITED AC 2014. [DOI: 10.3746/jkfn.2014.43.2.224] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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103
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Wu YY, Wu WY, Gong HL, Li WZ, Yin YY. Astragalosides attenuate learning and memory impairment in rats following ischemia‑reperfusion injury. Mol Med Rep 2014; 9:1319-24. [PMID: 24567111 DOI: 10.3892/mmr.2014.1969] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 02/03/2014] [Indexed: 11/06/2022] Open
Abstract
Astragalosides (ASTs) have been traditionally used in the treatment of various cardiovascular and cerebrovascular diseases. The aim of the present study was to investigate the neuroprotective effects of AST on learning and memory following focal cerebral ischemia/reperfusion in a rat model. A Morris water maze was used to measure the effect of AST on learning and memory impairments. A histological examination and Hoechst 33258 staining was used to observe the neuronal changes and apoptosis in the hippocampus. The activity of phospho-extracellular signal‑regulated kinases (p‑ERK), p‑c-Jun N-terminal kinases (JNK) and p‑Akt was measured by western blotting. The data revealed that AST improved the rats learning and memory abilities, attenuated neuronal cells apoptosis, increased the expression of p‑ERK and p‑Akt, and decreased the expression of p‑JNK. These findings indicated that AST has protective effects that may be correlated with the inhibition of neuronal cell apoptosis and the regulation of p‑ERK, p‑Akt and p‑JNK expression.
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Affiliation(s)
- Yang-Yang Wu
- Department of Pharmacology, Anhui Medical University, Key Laboratory of Chinese Medicine Research and Development, State Administration of Traditional Chinese Medicine, Hefei, Anhui 230032, P.R. China
| | - Wang-Yang Wu
- Department of Pharmacology, Anhui Medical University, Key Laboratory of Chinese Medicine Research and Development, State Administration of Traditional Chinese Medicine, Hefei, Anhui 230032, P.R. China
| | - Hui-Ling Gong
- Department of Pharmacology, Anhui Medical University, Key Laboratory of Chinese Medicine Research and Development, State Administration of Traditional Chinese Medicine, Hefei, Anhui 230032, P.R. China
| | - Wei-Zu Li
- Department of Pharmacology, Anhui Medical University, Key Laboratory of Chinese Medicine Research and Development, State Administration of Traditional Chinese Medicine, Hefei, Anhui 230032, P.R. China
| | - Yan-Yan Yin
- Department of Pharmacology, Anhui Medical University, Key Laboratory of Chinese Medicine Research and Development, State Administration of Traditional Chinese Medicine, Hefei, Anhui 230032, P.R. China
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104
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Neuroprotective role of a brain-enriched tyrosine phosphatase, STEP, in focal cerebral ischemia. J Neurosci 2013; 33:17814-26. [PMID: 24198371 DOI: 10.1523/jneurosci.2346-12.2013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The striatal-enriched phosphatase (STEP) is a component of the NMDA-receptor-mediated excitotoxic signaling pathway, which plays a key role in ischemic brain injury. Using neuronal cultures and a rat model of ischemic stroke, we show that STEP plays an initial role in neuroprotection, during the insult, by disrupting the p38 MAPK pathway. Degradation of active STEP during reperfusion precedes ischemic brain damage and is associated with secondary activation of p38 MAPK. Application of a cell-permeable STEP-derived peptide that is resistant to degradation and binds to p38 MAPK protects cultured neurons from hypoxia-reoxygenation injury and reduces ischemic brain damage when injected up to 6 h after the insult. Conversely, genetic deletion of STEP in mice leads to sustained p38 MAPK activation and exacerbates brain injury and neurological deficits after ischemia. Administration of the STEP-derived peptide at the onset of reperfusion not only prevents the sustained p38 MAPK activation but also reduces ischemic brain damage in STEP KO mice. The findings indicate a neuroprotective role of STEP and suggest a potential role of the STEP-derived peptide in stroke therapy.
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105
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Role of redox signaling in neuroinflammation and neurodegenerative diseases. BIOMED RESEARCH INTERNATIONAL 2013; 2013:484613. [PMID: 24455696 PMCID: PMC3884773 DOI: 10.1155/2013/484613] [Citation(s) in RCA: 243] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 10/30/2013] [Accepted: 11/21/2013] [Indexed: 01/14/2023]
Abstract
Reactive oxygen species (ROS), a redox signal, are produced by various enzymatic reactions and chemical processes, which are essential for many physiological functions and act as second messengers. However, accumulating evidence has implicated the pathogenesis of several human diseases including neurodegenerative disorders related to increased oxidative stress. Under pathological conditions, increasing ROS production can regulate the expression of diverse inflammatory mediators during brain injury. Elevated levels of several proinflammatory factors including cytokines, peptides, pathogenic structures, and peroxidants in the central nervous system (CNS) have been detected in patients with neurodegenerative diseases such as Alzheimer's disease (AD). These proinflammatory factors act as potent stimuli in brain inflammation through upregulation of diverse inflammatory genes, including matrix metalloproteinases (MMPs), cytosolic phospholipase A2 (cPLA2), cyclooxygenase-2 (COX-2), and adhesion molecules. To date, the intracellular signaling mechanisms underlying the expression of target proteins regulated by these factors are elusive. In this review, we discuss the mechanisms underlying the intracellular signaling pathways, especially ROS, involved in the expression of several inflammatory proteins induced by proinflammatory factors in brain resident cells. Understanding redox signaling transduction mechanisms involved in the expression of target proteins and genes may provide useful therapeutic strategies for brain injury, inflammation, and neurodegenerative diseases.
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106
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Nahirnyj A, Livne-Bar I, Guo X, Sivak JM. ROS detoxification and proinflammatory cytokines are linked by p38 MAPK signaling in a model of mature astrocyte activation. PLoS One 2013; 8:e83049. [PMID: 24376630 PMCID: PMC3871647 DOI: 10.1371/journal.pone.0083049] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 11/08/2013] [Indexed: 01/10/2023] Open
Abstract
Astrocytes are the most abundant glial cell in the retinal nerve fiber layer (NFL) and optic nerve head (ONH), and perform essential roles in maintaining retinal ganglion cell (RGC) detoxification and homeostasis. Mature astrocytes are relatively quiescent, but rapidly undergo a phenotypic switch in response to insult, characterized by upregulation of intermediate filament proteins, loss of glutamate buffering, secretion of pro-inflammatory cytokines, and increased antioxidant production. These changes result in both positive and negative influences on RGCs. However, the mechanism regulating these responses is still unclear, and pharmacologic strategies to modulate select aspects of this switch have not been thoroughly explored. Here we describe a system for rapid culture of mature astrocytes from the adult rat retina that remain relatively quiescent, but respond robustly when challenged with oxidative damage, a key pathogenic stress associated with inner retinal injury. When primary astrocytes were exposed to reactive oxygen species (ROS) we consistently observed characteristic changes in activation markers, along with increased expression of detoxifying genes, and secretion of proinflammatory cytokines. This in vitro model was then used for a pilot chemical screen to target specific aspects of this switch. Increased activity of p38α and β Mitogen Activated Protein Kinases (MAPKs) were identified as a necessary signal regulating expression of MnSOD, and heme oxygenase 1 (HO-1), with consequent changes in ROS-mediated injury. Additionally, multiplex cytokine profiling detected p38 MAPK-dependent secretion of IL-6, MCP-1, and MIP-2α, which are proinflammatory signals recently implicated in damage to the inner retina. These data provide a mechanism to link increased oxidative stress to proinflammatory signaling by astrocytes, and establish this assay as a useful model to further dissect factors regulating the reactive switch.
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Affiliation(s)
- Adrian Nahirnyj
- Department of Vision Sciences, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Izhar Livne-Bar
- Department of Vision Sciences, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Xiaoxin Guo
- Department of Vision Sciences, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Jeremy M. Sivak
- Department of Vision Sciences, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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107
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The roles of p38 MAPK/MSK1 signaling pathway in the neuroprotection of hypoxic postconditioning against transient global cerebral ischemia in adult rats. Mol Neurobiol 2013; 49:1338-49. [PMID: 24352802 DOI: 10.1007/s12035-013-8611-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 12/08/2013] [Indexed: 01/29/2023]
Abstract
Postconditioning has regenerated interest as a mechanical intervention against cerebral ischemia/reperfusion injury, but its molecular mechanisms remain unknown. We previously reported that hypoxic postconditioning (HPC) ameliorated neuronal death induced by transient global cerebral ischemia (tGCI) in hippocampal CA1 subregion of adult rats. This study tested the hypothesis that p38-mitogen-activated protein kinase (p38 MAPK)/mitogen- and stress-response kinase 1 (MSK1) signaling pathway plays a role in the HPC-induced neuroprotection. Male Wistar rats were subjected to 10 min ischemia induced by applying the four-vessel occlusion method. HPC with 120 min was applied at 24 h after reperfusion. Immunohistochemistry and Western blot were used to detect the expression of phosphorylation of p38 MAPK and MSK1, as well as cleaved caspase-3. We found that HPC induced a significant increase of phosphorylated p38 MAPK and MSK1 in neurons of hippocampal CA1 region and a significant decrease in glial cells after tGCI as well. Furthermore, HPC attenuated caspase-3 cleavation triggered by tGCI in CA1 region. Moreover, p38 MAPK inhibition by SB203580 significantly decreased the phosphorylation of MSK1, increased cleaved caspase-3 expression, and abolished the neuroprotection of HPC. These findings suggested that p38 MAPK/MSK1 signaling axis contributed to HPC-mediated neuroprotection against tGCI, at least in part, by regulating the activation of caspase-3.
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108
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Wang X, Jiang C, Wan H, Wu J, Quan W, Wu K, Li D. Neuroprotection against permanent focal cerebral ischemia by ginkgolides A and B is associated with obstruction of the mitochondrial apoptotic pathway via inhibition of c‐Jun N‐terminal kinase in rats. J Neurosci Res 2013; 92:232-42. [PMID: 24327346 DOI: 10.1002/jnr.23306] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 06/28/2013] [Accepted: 08/30/2013] [Indexed: 01/29/2023]
Affiliation(s)
- Xuan Wang
- Department of PharmacyPutuo People's HospitalShanghai China
| | - Cui‐Min Jiang
- Department of PharmacyPutuo People's HospitalShanghai China
| | - Hai‐Ying Wan
- Department of Clinical LaboratoryTongji Hospital of Tongji UniversityShanghai China
| | - Jun‐Lu Wu
- Department of Clinical LaboratoryTongji Hospital of Tongji UniversityShanghai China
| | - Wen‐Qiang Quan
- Department of Clinical LaboratoryTongji Hospital of Tongji UniversityShanghai China
| | - Kai‐Yin Wu
- Institute of PathologyCharité University HospitalBerlin Germany
| | - Dong Li
- Department of Clinical LaboratoryTongji Hospital of Tongji UniversityShanghai China
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109
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Yu K, Wu Y, Hu Y, Zhang Q, Xie H, Liu G, Chen Y, Guo Z, Jia J. Neuroprotective effects of prior exposure to enriched environment on cerebral ischemia/reperfusion injury in rats: the possible molecular mechanism. Brain Res 2013; 1538:93-103. [PMID: 24084470 DOI: 10.1016/j.brainres.2013.09.036] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 09/10/2013] [Accepted: 09/23/2013] [Indexed: 01/03/2023]
Abstract
Increasing evidence shows that exposure to an enriched environment (EE) after cerebral ischemia/reperfusion injury is neuroprotective in animal models. Recent studies have demonstrated that animals housed in an enriched environment condition after an experimental stroke obtained a better functional outcome than those housed in a standard condition. However, little is known about the underlying mechanisms of neuroprotective effects of enriched environment exposure prior to injury. The current study examined the neuroprotective effects of prior enriched environment exposure after transient middle cerebral artery occlusion (MCAO) in rats. Male Sprague Dawley (SD) rats, weighing 55-65g at the beginning of the experiment, were randomly assigned to a pre-ischemic enriched environment (PIEE) or pre-ischemic standard condition (PISC) group for 1 month. They were weighed on days1, 7, 18, and 28, and their locomotor activity was tracked during the period between 9:00am and 3:00pm daily. After 1 month, ischemia was induced by occluding the middle cerebral artery for 90min, followed by reperfusion. After approximately 24h of the operation, functional outcomes were assessed using the beam-walking test and a neurological evaluation scale in all rats. We measured the expression of extracellular signal regulated protein kinases1/2 (ERK1/2) by western blotting and gene expression levels of neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthasen (iNOS) by Real-Time PCR in the cortical area affected by ischemia. Finally, we measured the level of malondialdehyde (MDA) content, which is a biomarker of oxidative stress. The results showed that rats in the PIEE group had lighter weight than those in the PISC group. The functional outcomes of rats in the PIEE group were better than those in the PISC group, and substances associated with inflammation, such as MDA, nNOS, iNOS, and phospho-ERK1/2, were lower in the PIEE group compared with the PISC group. These results indicate that enriched environment may provide neuroprotection via ischemic preconditioning and enhance resilience to cerebral ischemia.
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Affiliation(s)
- Kewei Yu
- Department of Rehabilitation, Huashan Hospital, Fudan University, Shanghai, 200040, China; State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China
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110
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Zhang P, Hou J, Fu J, Li D, Zhang C, Liu J. Baicalin protects rat brain microvascular endothelial cells injured by oxygen-glucose deprivation via anti-inflammation. Brain Res Bull 2013; 97:8-15. [DOI: 10.1016/j.brainresbull.2013.05.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Revised: 05/10/2013] [Accepted: 05/13/2013] [Indexed: 11/30/2022]
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111
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Geldanamycin treatment during cerebral ischemia/reperfusion attenuates p44/42 mitogen-activated protein kinase activation and tissue damage. ACTA NEUROCHIRURGICA. SUPPLEMENT 2013; 118:39-43. [PMID: 23564101 DOI: 10.1007/978-3-7091-1434-6_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
BACKGROUND Heat-shock protein 90 (Hsp90) inhibitor geldanamycin was found to be neuroprotective in various experimental models of brain disease. The effect was attributed to the induction of heat-shock proteins and/or disruption of cellular signaling. METHODS In Sprague-Dawley rats, the middle cerebral artery was occluded for 90 min using the intraluminal suture method. Geldanamycin (300 mg/kg) or vehicle was injected intraperitoneally 15 min before onset of ischemia or reperfusion. Animals were sacrificed at 2, 4 or 24 h after ischemia onset and brain samples were processed for infarct volume measurement, Western blot analysis or immunofluorescent staining of Hsp90, Raf-1, p38, and p44/42 mitogen-activated protein kinases (MAPKs). RESULTS Geldanamycin treatment during ischemia or reperfusion reduced infarct volume by 79 and 61 % respectively. Geldanamycin decreased Raf-1 and activated p44/42 MAPK proteins, but did not alter levels of activated p38 MAPK during early reperfusion. Hsp90 was co-localized with Raf-1 and activated p44/42 MAPK in the cytoplasm of ischemic neurons. CONCLUSION Geldanamycin-induced protection against transient focal cerebral ischemia may in part be based upon depletion of Raf-1 and blockade of p44/42 MAPK activation.
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112
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Zhang F, Yin W, Chen J. Apoptosis in cerebral ischemia: executional and regulatory signaling mechanisms. Neurol Res 2013; 26:835-45. [PMID: 15727267 DOI: 10.1179/016164104x3824] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Programmed cell death, often in the form of apoptosis, is an important contributing mechanism in the pathogenesis of ischemic brain injury. Depending on the severity of the insult and the stage of the injury, the executional pathways that are directly responsible for cell death and the signaling mechanisms that participate in the regulation of these death pathways may vary. It is likely that molecular or pharmacological targeting of the upstream signaling mechanisms that control the death executional pathways may offer opportunities for more complete and long-term neuroprotection. This review summarizes the recent advancements in the understanding of the executional and regulatory signaling mechanisms in ischemic brain injury.
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Affiliation(s)
- Feng Zhang
- Department of Neurology and Institute of Neurodegenerative Disorders University of Pittsburgh School of Medicine Pittsburgh, Pennsylvania 15213, USA
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113
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Li W, Huang R, Shetty RA, Thangthaeng N, Liu R, Chen Z, Sumien N, Rutledge M, Dillon GH, Yuan F, Forster MJ, Simpkins JW, Yang SH. Transient focal cerebral ischemia induces long-term cognitive function deficit in an experimental ischemic stroke model. Neurobiol Dis 2013; 59:18-25. [PMID: 23845275 DOI: 10.1016/j.nbd.2013.06.014] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 06/19/2013] [Accepted: 06/25/2013] [Indexed: 01/27/2023] Open
Abstract
Vascular dementia ranks as the second leading cause of dementia in the United States. However, its underlying pathophysiological mechanism is not fully understood and no effective treatment is available. The purpose of the current study was to evaluate long-term cognitive deficits induced by transient middle cerebral artery occlusion (tMCAO) in rats and to investigate the underlying mechanism. Sprague-Dawley rats were subjected to tMCAO or sham surgery. Behavior tests for locomotor activity and cognitive function were conducted at 7 or 30days after stroke. Hippocampal long term potentiation (LTP) and involvement of GABAergic neurotransmission were evaluated at 30days after sham surgery or stroke. Immunohistochemistry and Western blot analyses were conducted to determine the effect of tMCAO on cell signaling in the hippocampus. Transient MCAO induced a progressive deficiency in spatial performance. At 30days after stroke, no neuron loss or synaptic marker change in the hippocampus were observed. LTP in both hippocampi was reduced at 30days after stroke. This LTP impairment was prevented by blocking GABAA receptors. In addition, ERK activity was significantly reduced in both hippocampi. In summary, we identified a progressive decline in spatial learning and memory after ischemic stroke that correlates with suppression of hippocampal LTP, elevation of GABAergic neurotransmission, and inhibition of ERK activation. Our results indicate that the attenuation of GABAergic activity or enhancement of ERK/MAPK activation in the hippocampus might be potential therapeutic approaches to prevent or attenuate cognitive impairment after ischemic stroke.
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Affiliation(s)
- Wenjun Li
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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114
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Li L, Deng J, Zuo Z. Glutamate transporter type 3 mediates isoflurane preconditioning-induced acute phase of neuroprotection in mice. Brain Res Bull 2013; 98:23-9. [PMID: 23827345 DOI: 10.1016/j.brainresbull.2013.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Revised: 06/19/2013] [Accepted: 06/24/2013] [Indexed: 11/26/2022]
Abstract
A pre-exposure to isoflurane reduces ischemic brain injury in rodents (isoflurane preconditioning). This neuroprotection has acute and delayed phases. Our previous in vitro studies suggest that the acute phase may involve excitatory amino acid transporters (EAATs). We determine whether this protection involves EAAT3, the major neuronal EAAT. Adult male EAAT3 knockout mice and their wild-type littermates were exposed or were not exposed to 1.5% isoflurane for 30 min. Sixty minutes later, they were subjected to a 90- or 60-min middle cerebral arterial occlusion (MCAO). Their neurological outcomes were evaluated 24h after the MCAO. In another experiment, cerebral cortex was harvested for Western blotting at 30 min after animals were exposed to 1.5% isoflurane for 30 min. Here, we showed that isoflurane reduced brain infarct volumes and improved neurological functions of wild-type mice after a 90-min MCAO. However, isoflurane pre-exposure did not change the neurological outcome of EAAT3 knockout mice no matter whether the MCAO was for 90 min or 60 min. Isoflurane increased phospho-Akt, a survival-promoting protein, in the wild-type mice but not in the EAAT3 knockout mice. The isoflurane-induced neuroprotection in the wild-type mice was abolished by LY294004, an Akt activation inhibitor. LY294004 alone did not affect the neurological outcome of the wild-type or EAAT3 knockout mice after focal brain ischemia. These results suggest that the isoflurane preconditioning-induced acute phase of neuroprotection involves EAAT3. The downstream event includes Akt activation.
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Affiliation(s)
- Liaoliao Li
- Department of Anesthesiology, University of Virginia, Charlottesville, VA, United States
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115
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Liu X, Ye M, An C, Pan L, Ji L. The effect of cationic albumin-conjugated PEGylated tanshinone IIA nanoparticles on neuronal signal pathways and neuroprotection in cerebral ischemia. Biomaterials 2013; 34:6893-905. [PMID: 23768781 DOI: 10.1016/j.biomaterials.2013.05.021] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 05/12/2013] [Indexed: 01/01/2023]
Abstract
Targeted treatment of ischemic stroke remains problem due to the complex pathogenesis of this disease and the difficulty in drug delivery across the blood-brain barrier (BBB). In the present study, the delivery efficiency of cationic bovine serum albumin-conjugated tanshinone IIA PEGylated nanoparticles (CBSA-PEG-TIIA-NPs) in rat brain was investigated. We further explored whether the protective mechanism of CBSA-PEG-TIIA-NPs in cerebral ischemia was associated with modulating neuronal signaling pathways. The experimental cerebral ischemia model was established to evaluate the treatment efficacy of CBSA-PEG-TIIA-NPs. The pharmacokinetics demonstrated that CBSA-PEG-TIIA-NPs could obviously prolong circulation time and increase plasma concentration compared with intravenously administrated TIIA solution. The biodistribution and brain uptake study confirmed that CBSA-PEG-TIIA-NPs possessed better brain delivery efficacy with a high drug accumulation and fluorescence quantitative level in brain. CBSA-PEG-TIIA-NPs effectively reduced infarction volume, neurological dysfunctions, neutrophils infiltration and neuronal apoptosis. Moreover, CBSA-PEG-TIIA-NPs significantly suppressed the expression of pro-inflammatory cytokines TNF-α and IL-8; upregulated the expression of anti-inflammatory cytokines IL-10 and increase TGF-β1 level in the ischemic brain. In addition, treatment with CBSA-PEG-TIIA-NPs markedly inhibited the mRNA expressions of GFAP, MMP-9, COX-2, p38MAPK, ERK1/2 and JNK, downregulated the protein levels of GFAP, MMP-9 and COX-2, as well as decreased the phosphorylation of ERK1/2, p38MAPK and JNK. These results demonstrated that CBSA-PEG-TIIA-NPs displayed remarkable neuroprotective effects on ischemic stroke through modulation of MAPK signal pathways involved in the cascades of neuroinflammation.
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Affiliation(s)
- Xin Liu
- College of Pharmaceutical Sciences, Zhejiang University, 310058 Hangzhou, China.
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116
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Jain V, Baitharu I, Prasad D, Ilavazhagan G. Enriched environment prevents hypobaric hypoxia induced memory impairment and neurodegeneration: role of BDNF/PI3K/GSK3β pathway coupled with CREB activation. PLoS One 2013; 8:e62235. [PMID: 23704876 PMCID: PMC3660501 DOI: 10.1371/journal.pone.0062235] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 03/18/2013] [Indexed: 11/28/2022] Open
Abstract
Adverse environmental conditions such as hypobaric hypoxia (HH) cause memory impairment by affecting cellular machinery leading to neurodegeneration. Providing enriched environment (EE) is found to be beneficial for curing several neurodegenerative disorders. The protective role of EE in preventing HH induced neuronal death has been reported previously but the involved mechanism is still not clearly understood. The present study is an attempt to verify the impact of EE on spatial memory during HH and also to explore the possible role of neurotrophin in EE mediated neuroprotection. Signaling mechanism involved in neuroprotection was also explored. Male Sprague Dawley rats were simulated to HH condition in an Animal Decompression Chamber at an altitude of 25000 feet in standard and enriched cages for 7 days. Spatial memory was assessed through Morris Water Maze. Role of different neurotrophins was explored by gene silencing and inhibitors for their respective receptors. Further, using different blockers signaling pathway was also explored. Finding of the present study suggested that EE prevents HH mediated memory impairment and neurodegeneration. Also brain-derived neurotrophic factor (BDNF) plays a major role in EE mediated neuroprotection and it effectively prevented neurodegeneration by activating PI3K/AKT pathway resulting in GSK3β inactivation which further inhibits apoptosis. Moreover GSK3β phosphorylation and hence its inactivation upregulates CREB phosphorylation which may also accounts for activation of survival machinery in cells and provides neuroprotection. From these observations it can be postulated that EE has a therapeutic potential in amelioration of HH induced memory impairment and neurodegeneration. Hence it may be used as a non invasive and non pharmacological intervention against various neurological disorders.
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Affiliation(s)
- Vishal Jain
- Department of Neurobiology, Defence Institute of Physiology and Allied Sciences (DIPAS), Delhi, India
| | - Iswar Baitharu
- Department of Neurobiology, Defence Institute of Physiology and Allied Sciences (DIPAS), Delhi, India
| | - Dipti Prasad
- Department of Neurobiology, Defence Institute of Physiology and Allied Sciences (DIPAS), Delhi, India
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117
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Kilic U, Yilmaz B, Reiter R, Yüksel A, Kilic E. Effects of memantine and melatonin on signal transduction pathways vascular leakage and brain injury after focal cerebral ischemia in mice. Neuroscience 2013; 237:268-76. [DOI: 10.1016/j.neuroscience.2013.01.059] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/21/2013] [Accepted: 01/22/2013] [Indexed: 12/09/2022]
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Sun X, Liu C, Qian M, Zhao Z, Guo J. Ceramide from sphingomyelin hydrolysis differentially mediates mitogen-activated protein kinases (MAPKs) activation following cerebral ischemia in rat hippocampal CA1 subregion. J Biomed Res 2013; 24:132-7. [PMID: 23554623 PMCID: PMC3596547 DOI: 10.1016/s1674-8301(10)60021-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Indexed: 01/08/2023] Open
Abstract
Objective To explore the role that ceramide plays in the activation of mitogen-activated protein kinases (MAPKs) during cerebral ischemia and reperfusion. Methods Rats were subjected to ischemia by the four-vessel occlusion (4-VO) method. The sphingomyelinase inhibitor TPCK was administered to the CA1 subregion of the rat hippocampus before inducing ischemia. Western blot was used to examine the activity of extracellular-signal regulated kinase (ERK) and c-Jun N-terminal protein kinase (JNK) using antibodies against ERK, JNK and diphosphorylated ERK and JNK. Results At 1h reperfusion post-ischemia, JNK reached its peak activity while ERK was undergoing a sharp inactivation (P < 0.05). The level of diphosphorylated JNK was significantly reduced but the sharp inactivation of ERK was visibly reversed (P < 0.05) by the sphingomyelinase inhibitor. Conclusion The ceramide signaling pathway is up-regulated through sphingomyelin hydrolysis in brain ischemia, promoting JNK activation and suppressing ERK activation, culminating in the ischemic lesion.
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Affiliation(s)
- Xian Sun
- The Laboratory Center for Basic Medical Sciences, Nanjing Medical University, Nanjing 210029, China ; Department of Biochemistry and Molecular Biology, Nanjing Medical University, Nanjing, 210029, China
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Palade C, Ciurea AV, Nica DA, Savu R, Moisa HA. Interference of apoptosis in the pathophysiology of subarachnoid hemorrhage. Asian J Neurosurg 2013; 8:106-11. [PMID: 24049554 PMCID: PMC3775181 DOI: 10.4103/1793-5482.116389] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Programmed cell death is crucial for the correct development of the organism and the clearance of harmful cells like tumor cells or autoreactive immune cells. Apoptosis is initiated by the activation of cell death receptors and in most cases it is associated with the activation of the cysteine proteases, which lead to apoptotic cell death. Cells shrink, chromatin clumps and forms a large, sharply demarcated, crescent-shaped or round mass; the nucleus condenses, apoptotic bodies are formed and eventually dead cells are engulfed by a neighboring cell or cleared by phagocytosis. The authors have summarized the most important data concerning apoptosis in subarachnoid hemorrhage that have been issued in the medical literature in the last 20 years.
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Affiliation(s)
- C. Palade
- Department of Neurosurgical, Carol Davila University School of Medicine, The National Center for Excellency in Neurosurgery, Bagdasar-Arseni Emergency Hospital, Bucharest, Romania
| | - Alexandru V. Ciurea
- Department of Neurosurgical, Carol Davila University School of Medicine, The National Center for Excellency in Neurosurgery, Bagdasar-Arseni Emergency Hospital, Bucharest, Romania
| | - D. A. Nica
- Department of Neurosurgical, Sf. Pantelimon Emergency Hospital, Bucharest, Romania
| | - R. Savu
- Department of Neurosurgical, Euromedica Hospital, Baia Mare, Romania
| | - Horatiu Alexandru Moisa
- Department of Neurosurgical, Carol Davila University School of Medicine, The National Center for Excellency in Neurosurgery, Bagdasar-Arseni Emergency Hospital, Bucharest, Romania
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Zhan L, Yan H, Zhou H, Sun W, Hou Q, Xu E. Hypoxic Preconditioning Attenuates Neuronal Cell Death by Preventing MEK/ERK Signaling Pathway Activation after Transient Global Cerebral Ischemia in Adult Rats. Mol Neurobiol 2013; 48:109-19. [DOI: 10.1007/s12035-013-8436-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 02/27/2013] [Indexed: 12/27/2022]
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Chen J, Guo Y, Cheng W, Chen R, Liu T, Chen Z, Tan S. High glucose induces apoptosis and suppresses proliferation of adult rat neural stem cells following in vitro ischemia. BMC Neurosci 2013; 14:24. [PMID: 23452440 PMCID: PMC3599336 DOI: 10.1186/1471-2202-14-24] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 02/27/2013] [Indexed: 01/13/2023] Open
Abstract
Background Post-stroke hyperglycemia appears to be associated with poor outcome from stroke, greater mortality, and reduced functional recovery. Focal cerebral ischemia data support that neural stem cells (NSCs) play an important role in post-ischemic repair. Here we sought to evaluate the negative effects of hyperglycemia on the cellular biology of NSCs following anoxia, and to test whether high glucose affects NSC recovery from ischemic injury. Results In this study, we used immortalized adult neural stem cells lines and we induced in vitro ischemia by 6 h oxygen and glucose deprivation (OGD) in an anaerobic incubator. Reperfusion was performed by returning cells to normoxic conditions and the cells were then incubated in experimental medium with various concentrations of glucose (17.5, 27.75, 41.75, and 83.75 mM) for 24 h. We found that high glucose (≥27.75 mM) exposure induced apoptosis of NSCs in a dose-dependent manner after exposure to OGD, using an Annexin V/PI apoptosis detection kit. The cell viability and proliferative activity of NSCs following OGD in vitro, evaluated with both a Cell Counting kit-8 (CCK-8) assay and a 5-ethynyl-2’-deoxyuridine (EdU) incorporation assay, were inhibited by high glucose exposure. Cell cycle analysis showed that high glucose exposure increased the percentage of cells in G0/G1-phase, and reduced the percentage of cells in S-phase. Furthermore, high glucose exposure was found to significantly induce the activation of c-Jun N-terminal protein kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) and suppress extracellular signal-regulated kinase 1/2 (ERK1/2) activity. Conclusions Our results demonstrate that high glucose induces apoptosis and inhibits proliferation of NSCs following OGD in vitro, which may be associated with the activation of JNK/p38 MAPK pathways and the delay of G1-S transition in the cells.
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Affiliation(s)
- Jian Chen
- Key Laboratory of Brain Function Repair and Regeneration of Guangdong, Department of Neurology, Zhujiang Hospital, Southern Medical University, Guangzhou, China
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Zhao L, Liu X, Liang J, Han S, Wang Y, Yin Y, Luo Y, Li J. Phosphorylation of p38 MAPK mediates hypoxic preconditioning-induced neuroprotection against cerebral ischemic injury via mitochondria translocation of Bcl-xL in mice. Brain Res 2013; 1503:78-88. [PMID: 23399686 DOI: 10.1016/j.brainres.2013.01.051] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 01/19/2013] [Accepted: 01/28/2013] [Indexed: 11/17/2022]
Abstract
Hypoxic preconditioning (HPC) initiates intracellular signaling pathway to provide protection, but the role of p38 mitogen-activated protein kinase (p38 MAPK) in HPC-induced neuroprotection against cerebral ischemic injuries is a matter of debate. In this study, we found that HPC could reduce 6h middle cerebral artery occlusion (MCAO)-induced infarct volume, edema ratio and cell apoptosis, as well as enhancing the up-regulated p38 MAPK phosphorylation (P-p38 MAPK) levels in the peri-infarct region of mice after 6h MCAO. However, intracerebroventricular injection of p38 MAPK inhibitor SB203580 abolished this HPC-induced neuroprotection. HPC significantly increased the translocation of anti-apoptotic Bcl-2-related protein Bcl-xL from the cytosol to the mitochondria in the peri-infarct region of MCAO mice. Interestingly, the results of reciprocal immunoprecipitation showed that Bcl-xL and P-p38 MAPK were coimmunoprecipitated reciprocally only in the peri-infarct region of HPC and MCAO treated mice, while Bcl-xL and total p38 (T-p38 MAPK), not P-p38 MAPK, could be coimmunoprecipited by each other in the brain of normal control mice. In addition, we found SB203580 significantly decreased P-p38 MAPK levels, and inhibited HPC-induced mitochondria translocation of Bcl-xL in the brain of HPC and MCAO treated mice. Taken together, our findings suggested that P-p38 MAPK mediates HPC-induced neuroprotection against cerebral ischemic injury via mitochondria translocation of Bcl-xL, which might be a key anti-cell apoptotic mechanism of HPC.
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Affiliation(s)
- Li Zhao
- Department of Neurobiology and Beijing Institute for Brain Disorders, Capital Medical University, Beijing 100069, China
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Ansar S, Eftekhari S, Waldsee R, Nilsson E, Nilsson O, Säveland H, Edvinsson L. MAPK signaling pathway regulates cerebrovascular receptor expression in human cerebral arteries. BMC Neurosci 2013; 14:12. [PMID: 23343134 PMCID: PMC3663811 DOI: 10.1186/1471-2202-14-12] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 12/26/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cerebral ischemia results in enhanced expression of contractile cerebrovascular receptors, such as endothelin type B (ET(B)), 5-hydroxytryptamine type 1B (5-HT(1B)), angiotensin II type 1 (AT(1)) and thromboxane (TP) receptors in the cerebral arteries within the ischemic area. The receptor upregulation occurs via activation of the mitogen-activated protein kinases (MAPK) pathway. Previous studies have shown that inhibitors of the MAPK pathway diminished the ischemic area and contractile cerebrovascular receptors after experimental cerebral ischemia. The aim of this study was to examine if the upregulation of contractile cerebrovascular receptors after 48 h of organ culture of human cerebral arteries involves MAPK pathways and if it can be prevented by a MEK1/2 inhibitor. Human cerebral arteries were obtained from patients undergoing intracranial tumor surgery. The vessels were divided into ring segments and incubated for 48 h in the presence or absence of the specific MEK1/2 inhibitor U0126. The vessels were then examined by using in vitro pharmacological methods and protein immunohistochemistry. RESULTS After organ culture of the cerebral arteries the contractile responses to endothelin (ET)-1, angiotensin (Ang) II and thromboxane (TP) were enhanced in comparison with fresh human arteries. However, 5-carboxamidotryptamine (5-CT) induced decreased contractile responses after organ culture as compared to fresh arteries. Incubation with U0126 diminished the maximum contraction elicited by application of ET-1, Ang II and U46619 in human cerebral arteries. In addition, the MEK1/2 inhibitor decreased the contractile response to 5-CT. Immunohistochemistry revealed that organ culture resulted in increased expression of endothelin ET(A), endothelin ET(B) angiotensin AT(2), 5-hydroxytryptamine 5-HT(1B) and thromboxane A2 receptors, and elevated levels of activated pERK1/2, all localized to the smooth muscle cells of the cerebral arteries. Co-incubation with U0126 normalized these proteins. CONCLUSION The study demonstrated that there is a clear association between human cerebrovascular receptor upregulation via transcription involving activation of the MAPK pathway after organ culture. Inhibition of the MAPK pathways attenuated the vasoconstriction mediated by ET, AT and TP receptors in human cerebral arteries and the enhanced expression of their receptors. The results indicate that MAPK inhibition might be a novel target for treatment of cerebrovascular disorders.
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Affiliation(s)
- Saema Ansar
- Department of Clinical Sciences, Division of Experimental Vascular Research, Lund University, Lund, Sweden.
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Gemfibrozil Pretreatment Resulted in a Sexually Dimorphic Outcome in the Rat Models of Global Cerebral Ischemia–Reperfusion via Modulation of Mitochondrial Pro-survival and Apoptotic Cell Death Factors as well as MAPKs. J Mol Neurosci 2013; 50:379-93. [DOI: 10.1007/s12031-012-9932-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 11/26/2012] [Indexed: 01/19/2023]
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Prevention of JNK phosphorylation as a mechanism for rosiglitazone in neuroprotection after transient cerebral ischemia: activation of dual specificity phosphatase. J Cereb Blood Flow Metab 2013; 33:106-14. [PMID: 23032483 PMCID: PMC3597369 DOI: 10.1038/jcbfm.2012.138] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Rosiglitazone, a synthetic peroxisome proliferator-activated receptor-γ (PPARγ) agonist, prevents cell death after cerebral ischemia in animal models, but the underlying mechanism has not been clarified. In this study, we examined how rosiglitazone protects neurons against ischemia. Mice treated with rosiglitazone were subjected to 60 minutes of focal ischemia followed by reperfusion. Rosiglitazone reduced infarct volume after ischemia and reperfusion. We show that this neuroprotective effect was reversed with a PPARγ antagonist. Western blot analysis showed a significant increase in expression of phosphorylated stress-activated protein kinases (c-Jun N-terminal kinase (JNK) and p38) in ischemic brain tissue. Rosiglitazone blocked this increase. Furthermore, we observed that rosiglitazone increased expression of the dual-specificity phosphatase 8 (DUSP8) protein and messenger RNA in ischemic brain tissue. Dual-specificity phosphatase 8 is a mitogen-activated protein kinase phosphatase that can dephosphorylate JNK and p38. Another key finding of the present study was that knockdown of DUSP8 in primary cultured cortical neurons that were subjected to oxygen-glucose deprivation diminished rosiglitazone's effect on downregulation of JNK phosphorylation. Thus, rosiglitazone's neuroprotective effect after ischemia is mediated by blocking JNK phosphorylation induced by ischemia via DUSP8 upregulation.
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126
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Dai R, Xia Y, Mao L, Mei Y, Xue Y, Hu B. Involvement of PI3K/Akt pathway in the neuroprotective effect of Sonic hedgehog on cortical neurons under oxidative stress. ACTA ACUST UNITED AC 2012; 32:856-860. [PMID: 23271286 DOI: 10.1007/s11596-012-1047-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Indexed: 01/11/2023]
Abstract
The Sonic hedgehog (SHH) signaling pathway plays a pivotal role in neurogenesis and brain damage repair. Our previous work demonstrated that the SHH signaling pathway was involved in the neuroprotection of cortical neurons against oxidative stress. The present study was aimed to further examine the underlying mechanism. The cortical neurons were obtained from one-day old Sprague-Dawley neonate rats. Hydrogen peroxide (H(2)O(2), 100 μmol/L) was used to treat neurons for 24 h to induce oxidative stress. Exogenous SHH (3 μg/mL) was employed to activate the SHH pathway, and cyclopamine (20 μmol/L), a specific SHH signal inhibitor, to block SHH pathway. LY294002 (20 μmol/L) were used to pre-treat the neurons 30 min before H(2)O(2) treatment and selectively inhibit the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. The cell viability was measured by MTT and apoptosis rate by flow cytometry analysis. The expression of p38, p-p38, ERK, p-ERK, Akt, p-Akt, Bcl-2, and Bax in neurons was detected by immunoblotting. The results showed that as compared with H(2)O(2) treatment, exogenous SHH could increase the expression of p-Akt by 20% and decrease the expression of p-ERK by 33%. SHH exerted no significant effect on p38 mitogen-activated protein kinase (p38 MAPK) pathway. Blockade of PI3K/Akt pathway by LY294002 decreased the cell viability by 17% and increased the cell apoptosis rate by 2-fold. LY294002 treatment could up-regulate the expression of the pro-apoptotic gene Bax by 12% and down-regulate the expression of the anti-apoptotic gene Bcl-2 by 54%. In conclusion, SHH pathway may activate PI3K/Akt pathway and inhibit the activation of the ERK pathway in neurons under oxidative stress. The PI3K/Akt pathway plays a key role in the neuroprotection of SHH. SHH/PI3K/Bcl-2 pathway may be implicated in the protection of neurons against H(2)O(2)-induced apoptosis.
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Affiliation(s)
- Ruolian Dai
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yuanpeng Xia
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Ling Mao
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yuanwu Mei
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Yumei Xue
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Bo Hu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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Itoh T, Tabuchi M, Mizuguchi N, Imano M, Tsubaki M, Nishida S, Hashimoto S, Matsuo K, Nakayama T, Ito A, Munakata H, Satou T. Neuroprotective effect of (-)-epigallocatechin-3-gallate in rats when administered pre- or post-traumatic brain injury. J Neural Transm (Vienna) 2012. [PMID: 23180302 DOI: 10.1007/s00702-012-0918-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Our previous study indicated that consuming (-)-epigallocatechin gallate (EGCG) before or after traumatic brain injury (TBI) eliminated free radical generation in rats, resulting in inhibition of neuronal degeneration and apoptotic death, and improvement of cognitive impairment. Here we investigated the effects of administering EGCG at various times pre- and post-TBI on cerebral function and morphology. Wistar rats were divided into five groups and were allowed access to (1) normal drinking water, (2) EGCG pre-TBI, (3) EGCG pre- and post-TBI, (4) EGCG post-TBI, and (5) sham-operated group with access to normal drinking water. TBI was induced with a pneumatic controlled injury device at 10 weeks of age. Immunohistochemistry and lipid peroxidation studies revealed that at 1, 3, and 7 days post-TBI, the number of 8-Hydroxy-2'-deoxyguanosine-, 4-Hydroxy-2-nonenal- and single-stranded DNA (ssDNA)-positive cells, and levels of malondialdehyde around the damaged area were significantly decreased in all EGCG treatment groups compared with the water group (P < 0.05). Although there was a significant increase in the number of surviving neurons after TBI in each EGCG treatment group compared with the water group (P < 0.05), significant improvement of cognitive impairment after TBI was only observed in the groups with continuous and post-TBI access to EGCG (P < 0.05). These results indicate that EGCG inhibits free radical-induced neuronal degeneration and apoptotic death around the area damaged by TBI. Importantly, continuous and post-TBI access to EGCG improved cerebral function following TBI. In summary, consumption of green tea may be an effective therapy for TBI patients.
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Affiliation(s)
- Tatsuki Itoh
- Department of Pathology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osakasayama, Osaka, 589-8511, Japan.
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Pluta R, Furmaga-Jabłońska W, Maciejewski R, Ułamek-Kozioł M, Jabłoński M. Brain ischemia activates β- and γ-secretase cleavage of amyloid precursor protein: significance in sporadic Alzheimer's disease. Mol Neurobiol 2012; 47:425-34. [PMID: 23080191 PMCID: PMC3538125 DOI: 10.1007/s12035-012-8360-z] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 09/27/2012] [Indexed: 12/21/2022]
Abstract
Amyloid precursor protein cleavage through β- and γ-secretases produces β-amyloid peptide, which is believed to be responsible for death of neurons and dementia in Alzheimer’s disease. Levels of β- and γ-secretase are increased in sensitive areas of the Alzheimer’s disease brain, but the mechanism of this process is unknown. In this review, we prove that brain ischemia generates expression and activity of both β- and γ-secretases. These secretases are induced in association with oxidative stress following brain ischemia. Data suggest that ischemia promotes overproduction and aggregation of β-amyloid peptide in brain, which is toxic for ischemic neuronal cells. In our review, we demonstrated the role of brain ischemia as a molecular link between the β- and the γ-secretase activities and provided a molecular explanation of the possible neuropathogenesis of sporadic Alzheimer’s disease.
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Affiliation(s)
- Ryszard Pluta
- Laboratory of Ischemic and Neurodegenerative Brain Research, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106, Warsaw, Pawińskiego 5 Str., Poland.
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129
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Ridder DA, Schwaninger M. TAK1 inhibition for treatment of cerebral ischemia. Exp Neurol 2012; 239:68-72. [PMID: 23022457 DOI: 10.1016/j.expneurol.2012.09.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 09/20/2012] [Indexed: 11/18/2022]
Abstract
TGFβ-activated kinase 1 (TAK1), a MAP3 kinase, is involved in at least five signaling cascades that modulate ischemic brain damage. Inhibition of TAK1 may therefore be an efficient way to interfere with multiple mechanisms in ischemic stroke. Indeed, a recent publication in Experimental Neurology confirmed that TAK1 inhibition by 5Z-7-oxozeaenol is neuroprotective. The beneficial effect of 5Z-7-oxozeaenol was associated with a reduced activation of Jun kinase that leads to inflammation and apoptosis. Recently, other TAK1 inhibitors were developed suggesting that TAK1 may prove as an efficient therapeutic target for neurodegenerative diseases if safety issues are not limiting.
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Affiliation(s)
- Dirk A Ridder
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Germany
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130
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Acute resveratrol treatment modulates multiple signaling pathways in the ischemic brain. Neurochem Res 2012; 37:2686-96. [PMID: 22878646 DOI: 10.1007/s11064-012-0858-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 07/15/2012] [Accepted: 07/28/2012] [Indexed: 12/19/2022]
Abstract
Resveratrol has several beneficial effects, including reductions of oxidative stress, inflammatory responses and apoptosis. It has been known that resveratrol is a sirtuin 1 (SIRT1) activator and protective effects of resveratrol are mediated by Akt and mitogen-activated protein kinases. However, it is not examined whether these pathways are regulated by resveratrol in the ischemic brain. Previously, we found that acute resveratrol treatment reduces brain injury induced by transient focal ischemic stroke. In the present study, we defined the signaling pathways modulated by resveratrol in ischemia by examining SIRT1 expression and phosphorylation of Akt, ERK1/2 and p38 in the ischemic cortex. Resveratrol increased expression of SIRT1 and phosphorylation of Akt and p38 but inhibited the increase in phosphorylation of ERK1/2. Gene and protein levels of peroxisome proliferator-activated receptor γ coactivator 1α, a downstream molecule of SIRT1, and mRNA levels of its target genes antioxidative superoxide dismutase 2 and uncoupling protein 2 were elevated. Resveratrol also increased phosphorylation of cyclic AMP-response-element-binding protein and transcription of the anti-apoptotic gene Bcl-2. These results suggest that various neuroprotective actions of resveratrol, including anti-oxidative, anti-apoptotic and inflammatory effects, are mediated via modulation of multiple signaling pathways in the ischemic brain.
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131
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Zhao Y, Luo P, Guo Q, Li S, Zhang L, Zhao M, Xu H, Yang Y, Poon W, Fei Z. Interactions between SIRT1 and MAPK/ERK regulate neuronal apoptosis induced by traumatic brain injury in vitro and in vivo. Exp Neurol 2012; 237:489-98. [PMID: 22828134 DOI: 10.1016/j.expneurol.2012.07.004] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Revised: 06/27/2012] [Accepted: 07/14/2012] [Indexed: 12/14/2022]
Abstract
Traumatic brain injury (TBI) is a serious insult that frequently leads to neurological dysfunction or death. Silent information regulator family protein 1 (SIRT1), as the founding member of nicotinamide adenine dinucleotide (NAD)-dependent deacetylases, has recently been demonstrated to have neuroprotective effect in several models of neurodegenerative diseases. The present study attempts to determine whether SIRT1 has a neuroprotective effect in the model of TBI, and further to investigate the possible regulatory mechanism of neuron death. Thus, we employ transection model in vitro and weight-drop model in vivo to mimic the insults of TBI. The study shows that the expressions of SIRT1, phosphorylation extracellular signal-regulated kinase (p-ERK) and cleaved Caspase-3 are induced after trauma injury in vitro or in vivo. Furthermore, inhibiting SIRT1 by pharmacological inhibitor salermide or SIRT1 siRNA significantly promotes apoptotic neuron death and reduces ERK1/2 activation induced by mechanical injury in vitro and in vivo. Inhibition of ERK1/2 activation with PD98059 or U0126 (two mitogen activated protein kinase kinase inhibitors) in vitro and in vivo significantly attenuates the SIRT1 and cleaved Caspase-3 expression to protect neuron against TBI-induced apoptosis. These results reveal that SIRT1 plays a neuroprotective effect against neuronal apoptosis induced by TBI. The interactions between SIRT1 and MAPK/ERK pathway regulate neuronal apoptosis induced by mechanical trauma injury in vitro and in vivo.
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Affiliation(s)
- Yongbo Zhao
- Institute of Neurosurgery, Xijing Hospital, Fourth Military Medical University, 17 Changlexi Street, Xi'an, Shaanxi Province 710032, People's Republic of China
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132
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Wang J, Jin H, Hua Y, Keep RF, Xi G. Role of protease-activated receptor-1 in brain injury after experimental global cerebral ischemia. Stroke 2012; 43:2476-82. [PMID: 22811450 DOI: 10.1161/strokeaha.112.661819] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND PURPOSE Evidence suggests that the protease-activated receptor-1 (PAR-1), a thrombin receptor, mediates neuronal injury in experimental cerebral ischemia. The present study investigated whether PAR-1 plays a role in brain injury after global cerebral ischemia. METHODS Adult male wild-type or PAR-1 knockout mice underwent a 20-minute bilateral common carotid artery occlusion or a sham operation. Behavior tests were performed before ischemia and 1, 2, and 3 days after bilateral common carotid artery occlusion. Mice were euthanized at different time points for thrombin activity, brain edema, Western blot analysis, and brain histology. RESULTS Thrombin activity and PAR-1 expression were increased in the brain after bilateral common carotid artery occlusion. Compared with wild-type mice, PAR-1 knockout mice had less brain edema formation, neuronal death, and behavior impairment after bilateral common carotid artery occlusion. In addition, bilateral common carotid artery occlusion-induced activation of mitogen-activated protein kinases was absent in PAR-1 knockout mice. CONCLUSIONS PAR-1 contributes to the brain injury induced by global cerebral ischemia, which may be related to activation of mitogen-activated protein kinases.
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Affiliation(s)
- Jinhu Wang
- Department of Neurosurgery, Room 5018 BSRB, University of Michigan, Ann Arbor, MI 48109-2200, USA
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Sirabella R, Secondo A, Pannaccione A, Molinaro P, Formisano L, Guida N, Di Renzo G, Annunziato L, Cataldi M. ERK1/2, p38, and JNK regulate the expression and the activity of the three isoforms of the Na+ /Ca2+ exchanger, NCX1, NCX2, and NCX3, in neuronal PC12 cells. J Neurochem 2012; 122:911-22. [PMID: 22708976 DOI: 10.1111/j.1471-4159.2012.07838.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
We evaluated whether changes in expression and activity of the three sodium/calcium exchanger isoforms, NCX1, NCX2, and NCX3 occurred in PC12 cells when the extracellular-signal-regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinases (JNK), and p38 mitogen-activated protein kinases (MAPKs) were silenced, pharmacologically blocked, or activated with nerve growth factor (NGF). Several findings suggesting that MAPKs control NCX emerged: (1) A decrease in NCX1 and NCX3 basal expression occurred when JNK or MEK1, the extracellular-signal-regulated kinases 1/2 upstream activator, were pharmacologically blocked, respectively; (2) NGF increased cAMP response element-binding 1 (CREB1) and Specificity Protein 1 (Sp1) binding to ncx1 promoter and CREB1 binding to two different sequences close to ncx2 transcription start site on genomic DNA; (3) An up-regulation of NCX1 and NCX3, abrogated upon either MEK1 or p38 blockade, and a down-regulation of NCX2, abolished upon p38 blockade, occurred upon NGF-induced MAPK activation. The NCX1 up-regulation was abolished upon either CREB1 or Sp1 silencing, whereas NCX2 down-regulation was abrogated only by CREB1 silencing. The NCX3 up-regulation was unaffected by CREB1 or Sp1 silencing and abolished upon proteasomal inhibition; (4) Whole-cell Na(+) /Ca(2+) exchange decreased when MEK1 and JNK were blocked and increased when MAPKs were activated by NGF. Collectively, these results demonstrate a MAPK-dependent regulation of NCX expression and activity which could be relevant in mediating some of the effects of MAPKs in neurons.
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134
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Nito C, Kamada H, Endo H, Narasimhan P, Lee YS, Chan PH. Involvement of mitogen-activated protein kinase pathways in expression of the water channel protein aquaporin-4 after ischemia in rat cortical astrocytes. J Neurotrauma 2012; 29:2404-12. [PMID: 22676888 DOI: 10.1089/neu.2012.2430] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Brain edema after ischemic brain injury is a key determinant of morbidity and mortality. Aquaporin-4 (AQP4) plays an important role in water transport in the central nervous system and is highly expressed in brain astrocytes. However, the AQP4 regulatory mechanisms are poorly understood. In this study, we investigated whether mitogen-activated protein kinases (MAPKs), which are involved in changes in osmolality, might mediate AQP4 expression in models of rat cortical astrocytes after ischemia. Increased levels of AQP4 in primary cultured astrocytes subjected to oxygen-glucose deprivation (OGD) and 2 h of reoxygenation were observed, after which they immediately decreased at 0 h of reoxygenation. Astrocytes exposed to OGD injury had significantly increased phosphorylation of three kinds of MAPKs. Treatment with SB203580, a selective p38 MAPK inhibitor, or SP600125, a selective c-Jun N-terminal kinase inhibitor, significantly attenuated the return of AQP4 to its normal level, and SB203580, but not SP600125, significantly decreased cell death. In an in vivo study, AQP4 expression was upregulated 1-3 days after reperfusion, which was consistent with the time course of p38 phosphorylation and activation, and decreased by the p38 inhibition after transient middle cerebral artery occlusion (MCAO). These results suggest that p38 MAPK may regulate AQP4 expression in cortical astrocytes after ischemic injury.
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Affiliation(s)
- Chikako Nito
- Division of Neurology, Nephrology, and Rheumatology, Department of Internal Medicine, Nippon Medical School, Tokyo, Japan.
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135
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Simão F, Matté A, Pagnussat AS, Netto CA, Salbego CG. Resveratrol preconditioning modulates inflammatory response in the rat hippocampus following global cerebral ischemia. Neurochem Int 2012; 61:659-65. [PMID: 22709670 DOI: 10.1016/j.neuint.2012.06.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Revised: 05/31/2012] [Accepted: 06/08/2012] [Indexed: 11/29/2022]
Abstract
Considerable evidence has been accumulated to suggests that blocking the inflammatory reaction promotes neuroprotection and shows therapeutic potential for clinical treatment of ischemic brain injury. Consequently, anti-inflammatory therapies are being explored for prevention and treatment of these diseases. Induction of brain tolerance against ischemia by pretreatment with resveratrol has been found to influence expression of different molecules. It remains unclear, however, whether and how resveratrol preconditioning changes expression of inflammatory mediators after subsequent global cerebral ischemia/reperfusion (I/R). Therefore, we investigated the effect of resveratrol pretreatment on NF-κB inflammatory cascade, COX-2, iNOS and JNK levels in experimental I/R. Adult male rats were subjected to 10 min of four-vessel occlusion and sacrificed at selected post-ischemic time points. Resveratrol (30 mg/kg) pretreatment was injected intraperitoneally 7 days prior to I/R induction. We found that resveratrol treatment before insult remarkably reduced astroglial and microglial activation at 7 days after I/R. It greatly attenuated I/R-induced NF-κB and JNK activation with decreased COX-2 and iNOS production. In conclusion, the neuroprotection of resveratrol preconditioning may be due in part to the suppression of the inflammatory response via regulation of NF-κB, COX-2 and iNOS induced by I/R. JNK was also suggested to play a protective role through in neuroprotection of resveratrol, which may also be contributing to reduction in neuroinflammation. The study adds to a growing literature that resveratrol can have important anti-inflammatory actions in the brain.
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Affiliation(s)
- Fabrício Simão
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, RS, Brazil.
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136
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Davalli AM, Perego C, Folli FB. The potential role of glutamate in the current diabetes epidemic. Acta Diabetol 2012; 49:167-83. [PMID: 22218826 DOI: 10.1007/s00592-011-0364-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 12/19/2011] [Indexed: 12/27/2022]
Abstract
In the present article, we propose the perspective that abnormal glutamate homeostasis might contribute to diabetes pathogenesis. Previous reports and our recent data indicate that chronically high extracellular glutamate levels exert direct and indirect effects that might participate in the progressive loss of β-cells occurring in both T1D and T2D. In addition, abnormal glutamate homeostasis may impact all the three accelerators of the "accelerator hypothesis" and could partially explain the rising frequency of T1D and T2D.
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Affiliation(s)
- Alberto M Davalli
- Diabetes and Endocrinology Unit, Department of Internal Medicine, San Raffaele Scientific Institute, 20132, Milan, Italy.
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137
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Biswas I, Garg I, Singh B, Khan GA. A key role of toll-like receptor 3 in tissue factor activation through extracellular signal regulated kinase 1/2 pathway in a murine hypoxia model. Blood Cells Mol Dis 2012; 49:92-101. [PMID: 22647506 DOI: 10.1016/j.bcmd.2012.05.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2012] [Revised: 04/27/2012] [Accepted: 04/30/2012] [Indexed: 11/18/2022]
Abstract
Hypoxemia in the circulation can lead to venous thrombosis (VT) through tissue factor (TF) activation, but the mechanism of TF activation in hypoxia remains obscure. Ligands released from damaged tissues or cells due to hypoxia are identified by various pattern-recognition receptors (PRR), including Toll-like receptor3 (TLR3). In the present study, we investigated the mechanism of TF activation during acute hypoxia in a rat model. The expression of TLR3 and TF was analyzed by immunoblotting and RT-PCR. The TF activity was evaluated by two-stage chromogenic assay and fibrin deposition was detected by immunohistochemistry. The expression of TLR3, TF, and TF activity was increased significantly 6 h post acute hypoxia and then decreased gradually. The contribution of TLR3 in TF activation was investigated by poly I:C and TLR3 neutralizing antibody. We also found increased ERK phosphorylation both in acute hypoxia and poly I:C treatment. We further showed that the pre-treatment of TLR3 neutralizing antibody or ERK inhibitor (PD98059) 2 h prior to acute hypoxia or poly I:C treatment completely abrogated ERK phosphorylation and TF activation. The pre-treatment of TLR3 neutralizing antibody also inhibited fibrin deposition in lung vasculature. These data indicate that acute hypoxia induced TF activation is mediated through TLR3-ERK1/2 pathway.
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Affiliation(s)
- Indranil Biswas
- Hematology Group, Defence Institute of Physiology and Allied Sciences, India
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138
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Tissue kallikrein protects neurons from hypoxia/reoxygenation-induced cell injury through Homer1b/c. Cell Signal 2012; 24:2205-15. [PMID: 22575735 DOI: 10.1016/j.cellsig.2012.04.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 04/27/2012] [Indexed: 11/24/2022]
Abstract
Previous studies have demonstrated that human tissue kallikrein (TK) gene delivery protects against mouse cerebral ischemia/reperfusion (I/R) injury through bradykinin B2 receptor (B2R) activation. We have also reported that exogenous TK administration can suppress glutamate- or acidosis-induced neurotoxicity through the extracellular signal-regulated kinase1/2 (ERK1/2) pathway. To further explore the neuroprotection mechanisms of TK, in the present study we performed immunoprecipitation analysis and identified a scaffolding protein Homer1b/c using MALDI-TOF MS analysis. Here, we tested the hypothesis that TK reduces cell injury induced by oxygen and glucose deprivation/reoxygenation (OGD/R) through activating Homer1b/c. We found that TK increased the expression of Homer1b/c in a concentration- and time-dependent manner. Moreover, TK facilitated the translocation of Homer1b/c to the plasma membrane under OGD/R condition by confocal microscope assays. We also observed that overexpression of Homer1b/c showed the neuroprotection against OGD/R-induced cell injury by enhancing cell survival, reducing LDH release, caspase-3 activity and cell apoptosis. However, the knockdown of Homer1b/c by small interfering RNA showed the opposite effects, indicating that Homer1b/c had protective effects against OGD/R-induced neuronal injury. More interestingly, TK exerted its much more significantly neuroprotective effects after Homer1b/c overexpression, whereas it exerted its reduced effects after Homer1b/c knockdown. In addition, TK pretreatment increased the phosphorylation of the ERK1/2 and Akt-GSK3β through Homer1b/c activation. The beneficial effects of Homer1b/c were abolished by the ERK1/2 or PI3K antagonist. Therefore, we propose novel signaling mechanisms involved in the anti-hypoxic function of TK through activation of Homer1b/c-ERK1/2 and Homer1b/c-PI3K-Akt signaling pathways.
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139
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Phosphorylation of HSP27 by protein kinase D is essential for mediating neuroprotection against ischemic neuronal injury. J Neurosci 2012; 32:2667-82. [PMID: 22357851 DOI: 10.1523/jneurosci.5169-11.2012] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Heat shock protein 27 (HSP27) (or HSPB1) exerts cytoprotection against many cellular insults, including cerebral ischemia. We previously identified apoptosis signal-regulating kinase 1 (ASK1) as a critical downstream target of HSP27 conferring the neuroprotective effects of HSP27 against neuronal ischemia. However, the function of HSP27 is highly influenced by posttranslational modification, with differential cellular effects based on phosphorylation at specific serine residues. The role of phosphorylation in neuronal ischemic neuroprotection is currently unknown. We have created transgenic mice and viral vectors containing HSP27 mutated at three critical serine residues (Ser15, Ser78, and Ser82) to either alanine (HSP27-A, nonphosphorylatable) or aspartate (HSP27-D, phosphomimetic) residues. Under both in vitro and in vivo neuronal ischemic settings, overexpression of wild-type HSP27 (HSP27) and HSP27-D, but not HSP27-A, was neuroprotective and inhibited downstream ASK1 signaling pathways. Consistently, overexpressed HSP27 was phosphorylated by endogenous mechanisms when neurons were under ischemic stress, and single-point mutations identified Ser15 and Ser82 as critical for neuroprotection. Using a panel of inhibitors and gene knockdown approaches, we identified the upstream kinase protein kinase D (PKD) as the primary kinase targeting HSP27 directly for phosphorylation. PKD and HSP27 coimmunoprecipitated, and inhibition or knockdown of PKD abrogated the neuroprotective effects of HSP27 as well as the interaction with and inhibition of ASK1 signaling. Together, these data demonstrate that HSP27 requires PKD-mediated phosphorylation for its suppression of ASK1 cell death signaling and neuroprotection against ischemic injury.
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140
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Prokineticin 2 is an endangering mediator of cerebral ischemic injury. Proc Natl Acad Sci U S A 2012; 109:5475-80. [PMID: 22431614 DOI: 10.1073/pnas.1113363109] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Stroke causes brain dysfunction and neuron death, and the lack of effective therapies heightens the need for new therapeutic targets. Here we identify prokineticin 2 (PK2) as a mediator for cerebral ischemic injury. PK2 is a bioactive peptide initially discovered as a regulator of gastrointestinal motility. Multiple biological roles for PK2 have been discovered, including circadian rhythms, angiogenesis, and neurogenesis. However, the role of PK2 in neuropathology is unknown. Using primary cortical cultures, we found that PK2 mRNA is up-regulated by several pathological stressors, including hypoxia, reactive oxygen species, and excitotoxic glutamate. Glutamate-induced PK2 expression is dependent on NMDA receptor activation and extracellular calcium. Enriched neuronal culture studies revealed that neurons are the principal source of glutamate-induced PK2. Using in vivo models of stroke, we found that PK2 mRNA is induced in the ischemic cortex and striatum. Central delivery of PK2 worsens infarct volume, whereas PK2 receptor antagonist decreases infarct volume and central inflammation while improving functional outcome. Direct central inhibition of PK2 using RNAi also reduces infarct volume. These findings indicate that PK2 can be activated by pathological stimuli such as hypoxia-ischemia and excitotoxic glutamate and identify PK2 as a deleterious mediator for cerebral ischemia.
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141
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Thauerer B, Zur Nedden S, Baier-Bitterlich G. Purine nucleosides: endogenous neuroprotectants in hypoxic brain. J Neurochem 2012; 121:329-42. [PMID: 22335456 PMCID: PMC3499684 DOI: 10.1111/j.1471-4159.2012.07692.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Even a short blockade of oxygen flow in brain may lead to the inhibition of oxidative phosphorylation and depletion of cellular ATP, which results in profound deficiencies in cellular function. Following ischemia, dying, injured, and hypoxic cells release soluble purine-nucleotide and -nucleoside pools. Growing evidence suggests that purine nucleosides might act as trophic factors in the CNS and PNS. In addition to equilibrative nucleoside transporters (ENTs) regulating purine nucleoside concentrations intra- and extracellularly, specific extracellular receptor subtypes for these compounds are expressed on neurons, glia, and endothelial cells, mediating stunningly diverse effects. Such effects range from induction of cell differentiation, apoptosis, mitogenesis, and morphogenetic changes, to stimulation of synthesis and/or release of cytokines and neurotrophic factors under both physiological and pathological conditions. Multiple signaling pathways regulate the critical balance between cell death and survival in hypoxia-ischemia. A convergent pathway for the regulation of multiple modalities involved in O₂ sensing is the mitogen activated protein kinase (p42/44 MAPK) or (ERK1/2 extracellular signal-regulated kinases) pathway terminating in a variety of transcription factors, for example, hypoxia-inducible factor 1α. In this review, the coherence of purine nucleoside-related pathways and MAPK activation in the endogenous neuroprotective regulation of the nervous system's development and neuroplasticity under hypoxic stress will be discussed.
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Affiliation(s)
- Bettina Thauerer
- Division of Neurobiochemistry, Biocenter Department, Medical University of Innsbruck, Innsbruck, Austria
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142
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Echeverry R, Wu F, Haile WB, Wu J, Yepes M. The cytokine tumor necrosis factor-like weak inducer of apoptosis and its receptor fibroblast growth factor-inducible 14 have a neuroprotective effect in the central nervous system. J Neuroinflammation 2012; 9:45. [PMID: 22394384 PMCID: PMC3311607 DOI: 10.1186/1742-2094-9-45] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 03/06/2012] [Indexed: 12/11/2022] Open
Abstract
Background Cerebral cortical neurons have a high vulnerability to the harmful effects of hypoxia. However, the brain has the ability to detect and accommodate to hypoxic conditions. This phenomenon, known as preconditioning, is a natural adaptive process highly preserved among species whereby exposure to sub-lethal hypoxia promotes the acquisition of tolerance to a subsequent lethal hypoxic injury. The cytokine tumor necrosis factor-like weak inducer of apoptosis (TWEAK) and its receptor fibroblast growth factor-inducible 14 (Fn14) are found in neurons and their expression is induced by exposure to sub-lethal hypoxia. Accordingly, in this work we tested the hypothesis that the interaction between TWEAK and Fn14 induces tolerance to lethal hypoxic and ischemic conditions. Methods Here we used in vitro and in vivo models of hypoxic and ischemic preconditioning, an animal model of transient middle cerebral artery occlusion and mice and neurons genetically deficient in TWEAK, Fn14, or tumor necrosis factor alpha (TNF-α) to investigate whether treatment with recombinant TWEAK or an increase in the expression of endogenous TWEAK renders neurons tolerant to lethal hypoxia. We used enzyme-linked immunosorbent assay to study the effect of TWEAK on the expression of neuronal TNF-α, Western blot analysis to investigate whether the effect of TWEAK was mediated by activation of mitogen-activated protein kinases and immunohistochemical techniques and quantitative real-time polymerase chain reaction analysis to study the effect of TWEAK on apoptotic cell death. Results We found that either treatment with recombinant TWEAK or an increase in the expression of TWEAK and Fn14 induce hypoxic and ischemic tolerance in vivo and in vitro. This protective effect is mediated by neuronal TNF-α and activation of the extracellular signal-regulated kinases 1 and 2 pathway via phosphorylation and inactivation of the B-cell lymphoma 2-associated death promoter protein. Conclusions Our work indicate that the interaction between TWEAK and Fn14 triggers the activation of a cell signaling pathway that results in the induction of tolerance to lethal hypoxia and ischemia. These data indicate that TWEAK may be a potential therapeutic strategy to protect the brain from the devastating effects of an ischemic injury.
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Affiliation(s)
- Ramiro Echeverry
- Department of Neurology and Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA, USA
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143
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Kilic U, Yilmaz B, Ugur M, Yüksel A, Reiter RJ, Hermann DM, Kilic E. Evidence that membrane-bound G protein-coupled melatonin receptors MT1 and MT2 are not involved in the neuroprotective effects of melatonin in focal cerebral ischemia. J Pineal Res 2012; 52:228-35. [PMID: 21913972 DOI: 10.1111/j.1600-079x.2011.00932.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Melatonin is synthesized and released by the pineal gland in a circadian rhythm, and many of its peripheral actions are mediated via membrane MT1 and MT2 receptors. Apart from its metabolic functions, melatonin is a potent neuroprotective molecule owing to its antioxidative actions. The roles of MT1 and MT2 in the neuroprotective effects of melatonin and cell signaling after cerebral ischemia remain unknown. With the use of MT1 and MT2 knockout (mt1/2(-/-) ) mice treated with melatonin, we evaluated brain injury, edema formation, inducible nitric oxide synthase (iNOS) activity, and signaling pathways, including CREB, ATF-1, p21, Jun kinase (JNK)1/2, p38 phosphorylation, resulting from ischemia/reperfusion injury. We show that the infarct volume and brain edema do not differ between mt1/2(-/-) and wild-type (WT) animals, but melatonin treatment decreases infarct volume in both groups and brain edema in WT animals after middle cerebral artery occlusion. Notably, melatonin's neuroprotective effect was even more pronounced in mt1/2(-/-) animals compared to that in WT animals. We also demonstrate that melatonin treatment decreased CREB, ATF-1, and p38 phosphorylation in both mt1/2(-/-) and WT mice, while p21 and JNK1/2 were reduced only in melatonin-treated WT animals in the ischemic hemisphere. Furthermore, melatonin treatment lowered iNOS activity only in WT animals. We provide evidence that the absence of MT1 and MT2 has no unfavorable effect on ischemic brain injury. In addition, the neuroprotective effects of melatonin appear to be mediated through a mechanism independent of its membrane receptors. The underlying mechanism(s) should be further studied using selective melatonin receptor agonists and antagonists.
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Affiliation(s)
- Ulkan Kilic
- Department of Medical Biology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, Turkey
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144
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Itoh T, Imano M, Nishida S, Tsubaki M, Mizuguchi N, Hashimoto S, Ito A, Satou T. Increased apoptotic neuronal cell death and cognitive impairment at early phase after traumatic brain injury in aged rats. Brain Struct Funct 2012; 218:209-20. [PMID: 22374222 DOI: 10.1007/s00429-012-0394-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 01/31/2012] [Indexed: 01/29/2023]
Abstract
Progressive age-associated increases in cerebral dysfunction have been shown to occur following traumatic brain injury (TBI). Moreover, levels of neuronal mitochondrial antioxidant enzymes in the aged brain are reduced, resulting in free radical-induced cell death. It was hypothesized that cognitive impairment after TBI in the aged progresses to a greater degree than in younger individuals, and that damage involves neuronal degeneration and death by free radicals. In this study, we investigated the effects of free radicals on neuronal degeneration, cell death, and cognitive impairment in 10-week-old (young group) and 24-month-old rats (aged group) subjected to TBI. Young and aged rats received TBI with a pneumatic controlled injury device. At 1, 3 and 7 days after TBI, immunohistochemistry, lipid peroxidation and behavioral studies were performed. At 1, 3 and 7 days post-TBI, the number of 8-hydroxy-2'-deoxyguanosine-, 4-hydroxy-2-nonenal- and single-stranded DNA (ssDNA)-positive cells, and the levels of malondialdehyde around the damaged area after TBI significantly increased in the aged group when compared with the young group (P < 0.05). In addition, the majority of ssDNA-positive cells in both groups co-localized with neuronal cells around the damaged area. There was a significant decrease in the number of surviving neurons and an increase in cognitive impairment after TBI in the aged group when compared with the young group (P < 0.05). These results indicate that following TBI, high levels of free radicals are produced in the aged rat brain, which induces neuronal degeneration and apoptotic cell death around the damaged area, resulting in cognitive impairment.
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Affiliation(s)
- Tatsuki Itoh
- Department of Pathology, Faculty of Medicine, Kinki University, 377-2 Ohno-higashi, Osakasayama, Osaka 589-8511, Japan.
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Wallace BK, Jelks KA, O'Donnell ME. Ischemia-induced stimulation of cerebral microvascular endothelial cell Na-K-Cl cotransport involves p38 and JNK MAP kinases. Am J Physiol Cell Physiol 2012; 302:C505-17. [PMID: 22049209 PMCID: PMC3287160 DOI: 10.1152/ajpcell.00261.2011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 10/28/2011] [Indexed: 11/22/2022]
Abstract
Previous studies have provided evidence that, in the early hours of ischemic stroke, a luminal membrane blood-brain barrier (BBB) Na-K-Cl cotransporter (NKCC) participates in ischemia-induced cerebral edema formation. Inhibition of BBB NKCC activity by intravenous bumetanide significantly reduces edema and infarct in the rat permanent middle cerebral artery occlusion model of ischemic stroke. We demonstrated previously that the BBB cotransporter is stimulated by hypoxia, aglycemia, and AVP, factors present during cerebral ischemia. However, the underlying mechanisms have not been known. Ischemic conditions have been shown to activate p38 and JNK MAP kinases (MAPKs) in brain, and the p38 and JNK inhibitors SB-239063 and SP-600125, respectively, have been found to reduce brain damage following middle cerebral artery occlusion and subarachnoid hemorrhage, respectively. The present study was conducted to determine whether one or both of these MAPKs participates in ischemic factor stimulation of BBB NKCC activity. Cultured cerebral microvascular endothelial cell NKCC activity was evaluated as bumetanide-sensitive (86)Rb influx. Activities of p38 and JNK were assessed by Western blot and immunofluorescence methods using antibodies that detect total vs. phosphorylated (activated) p38 or JNK. We report that p38 and JNK are present in cultured cerebral microvascular endothelial cells and in BBB endothelial cells in situ and that hypoxia (7% O(2) and 2% O(2)), aglycemia, AVP, and O(2)-glucose deprivation (5- to 120-min exposures) all rapidly activate p38 and JNK in the cells. We also provide evidence that SB-239063 and SP-600125 reduce or abolish ischemic factor stimulation of BBB NKCC activity. These findings support the hypothesis that ischemic factor stimulation of the BBB NKCC involves activation of p38 and JNK MAPKs.
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Affiliation(s)
- Breanna K Wallace
- Dept. of Physiology and Membrane Biology, School of Medicine, Univ. of California, Davis, CA 95616, USA
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146
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Zhang L, Qu Y, Tang B, Zhao F, Xiong T, Ferriero D, Mu D. Integrin β8 Signaling in Neonatal Hypoxic–Ischemic Brain Injury. Neurotox Res 2012; 22:280-91. [DOI: 10.1007/s12640-012-9312-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2011] [Revised: 01/10/2012] [Accepted: 01/16/2012] [Indexed: 11/24/2022]
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147
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Cathepsin B and phospo-JNK in relation to ongoing apoptosis after transient focal cerebral ischemia in the rat. Neurochem Res 2012; 37:948-57. [PMID: 22270907 DOI: 10.1007/s11064-011-0687-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2011] [Revised: 12/19/2011] [Accepted: 12/22/2011] [Indexed: 10/14/2022]
Abstract
Cathepsin B, one of major lysosomal cathepsins, and JNK, a downstream component of Rho kinase (ROCK), are two families of proteases, which play an important role in ischemic cell apoptosis. However, the interrelationship between Cathepsin B and JNK in apotosis has not been examined. In the present study, rats were decapitated at 0, 2, 6, 24, 48 h of reperfusion after 2 h of middle cerebral artery occlusion (MCAO); TUNEL-positive cells appeared in the ipsilateral preoptic region during reperfusion after 2-h MCAO, and gradually increased to a peak of 24 h after reperfusion; Phospho-JNK (p-JNK) immunoreactivity, occurring after Cathepsin B expression, was gradually increased and peaked altogether with Cathepsin B at 6-h reperfusion; Fasudil (5 mg/kg, intraperitoneally), an inhibitor of ROCK, decreased the level of p-JNK and apoptotic neurons, and had no effect on cathepsin B; Immunofluorescent double labeling showed that the colocalization of cathepsin B with p-JNK appeared in the preoptic region at 2, 6, 24, 48 h of reperfusion. These findings indicate that a signal transduction pathway by ischemia-reperfusion is most likely to exist: lysosomal cathepsin B-Rho/Rho kinase pathway-JNK signaling pathway-mitochondrial-dependent intrinsic pathway.
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148
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Kim JY, Jeong HY, Lee HK, Kim S, Hwang BY, Bae K, Seong YH. Neuroprotection of the leaf and stem of Vitis amurensis and their active compounds against ischemic brain damage in rats and excitotoxicity in cultured neurons. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2012; 19:150-159. [PMID: 21778042 DOI: 10.1016/j.phymed.2011.06.015] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 03/31/2011] [Accepted: 06/16/2011] [Indexed: 05/31/2023]
Abstract
Vitis amurensis (Vitaceae) has been reported to have anti-oxidant and anti-inflammatory activities. The present study investigated a methanol extract from the leaf and stem of V. amurensis for neuroprotective effects on cerebral ischemic damage in rats and on excitotoxicity induced by glutamate in cultured rat cortical neurons. Transient focal cerebral ischemia was induced by 2h middle cerebral artery occlusion followed by 24h reperfusion (MCAO/reperfusion) in rats. Orally administered V. amurensis (25-100 mg/kg) reduced MCAO/reperfusion-induced infarct and edema formation, neurological deficits, and neuronal death. Depletion of glutathione (GSH) level and lipid peroxidation induced by MCAO/reperfusion was inhibited by administration of V. amurensis. The increase of phosphorylated mitogen-activated protein kinases (MAPKs), cyclooxygenase-2 (COX-2), and pro-apoptotic proteins and the decrease of anti-apoptotic protein in MCAO/reperfusion rats were significantly inhibited by treatment with V. amurensis. Exposure of cultured cortical neurons to 500 μM glutamate for 12h induced neuronal cell death. V. amurensis (1-50 μg/ml) and (+)-ampelopsin A, γ-2-viniferin, and trans-ε-viniferin isolated from the leaf and stem of V. amurensis inhibited glutamate-induced neuronal death, the elevation of intracellular calcium ([Ca(2+)](i)), the generation of reactive oxygen species (ROS), and changes of apoptosis-related proteins in cultured cortical neurons, suggesting that the neuroprotective effect of V. amurensis may be partially attributed to these compounds. These results suggest that the neuroprotective effect of V. amurensis against focal cerebral ischemic injury might be due to its anti-apoptotic effect, resulting from anti-excitotoxic, anti-oxidative, and anti-inflammatory effects and that the leaf and stem of V. amurensis have possible therapeutic roles for preventing neurodegeneration in stroke.
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Affiliation(s)
- Joo Youn Kim
- College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea
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149
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Itoh T, Imano M, Nishida S, Tsubaki M, Mizuguchi N, Hashimoto S, Ito A, Satou T. (-)-Epigallocatechin-3-gallate increases the number of neural stem cells around the damaged area after rat traumatic brain injury. J Neural Transm (Vienna) 2012; 119:877-90. [PMID: 22212485 DOI: 10.1007/s00702-011-0764-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 12/25/2011] [Indexed: 10/14/2022]
Abstract
A major component of green tea is (-)-epigallocatechin gallate (EGCG), which has strong antioxidant properties. Here, we investigated the effect of EGCG on neural stem cell (NSC) proliferation around the damaged area following traumatic brain injury (TBI). In this study, male Wistar rats that had access to normal drinking water, or water containing 0.1% (w/v) EGCG, ad libitum received TBI at 10 weeks of age. Immunohistochemistry revealed that the number of nestin-positive cells around the damaged area after TBI in the EGCG treatment group increased significantly compared with the normal water group (P < 0.05). However, the number of 8-hydroxy-2'-deoxyguanosine-, 4-hydroxy-2-nonenal-, single-stranded DNA (ssDNA)-positive cells and the level of peroxidation around the damaged area after TBI significantly decreased in the EGCG treatment group when compared with the water group (P < 0.05). Furthermore, in contrast to the EGCG group, almost all ssDNA-positive cells in the water group co-localized with NeuN and nestin-staining. Ex vivo studies revealed that spheres could only be isolated from injured brain tissue in the water group at 3 days following TBI. However, in the EGCG group, spheres could be isolated at both 3 and 7 days following TBI. A greater number of spheres could be isolated from the EGCG group, which differentiated into neurons and glia in culture without basic fibroblast growth factor. These results indicate that consumption of water containing EGCG pre- and post-TBI inhibits free radical-induced degradation of NSCs, which have the potential to differentiate into neurons and glia around the area of damage following TBI.
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Affiliation(s)
- Tatsuki Itoh
- Department of Pathology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osakasayama, Osaka, Japan.
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150
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Su X, Zhu CL, Shi W, Ni LC, Shen JH, Chen J. Transient global cerebral ischemia induces up-regulation of MLTKα in hippocampal CA1 neurons. J Mol Histol 2011; 43:187-93. [PMID: 22146853 DOI: 10.1007/s10735-011-9381-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 11/28/2011] [Indexed: 11/26/2022]
Abstract
MLTK (mixed-lineage kinase-like mitogen-activated protein triple kinase) is a member of the mitogen-activated protein kinase family and functioned as a mitogen activated kinase kinase kinase. MLTKα, one of the alternatively spliced forms of MLTK, could activate the c-Jun N-terminal kinase pathway, which involved in cellular stress responses and apoptosis. But the role of MLTKα in neural apoptosis was still unclear. Here, we performed a transient global cerebral ischemia model (TGCI) in adult rats and detected the dynamic changes of MLTKα in hippocampal CA1 neurons and brain cortex. We found the MLTKα expression was increased shortly after TGCI and peaked after 8 h. In spatial distribution, MLTKα was widely located in neurons rather than astrocytes and microglia. Moreover, there was a concomitant up-regulation of active caspase-3. Taken together, we hypothesized the up-regulation of MLTKα played an essential role in the apoptosis of hippocampal CA1 neurons.
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Affiliation(s)
- Xing Su
- Department of Neurosurgery, Surgical Research Center, Hospital Affiliated to Nantong University, Xisi Road 20#, Nantong, 226001, Jiangsu, China
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