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Park JH, Lo EH, Hayakawa K. Endoplasmic Reticulum Interaction Supports Energy Production and Redox Homeostasis in Mitochondria Released from Astrocytes. Transl Stroke Res 2021; 12:1045-1054. [PMID: 33479917 PMCID: PMC8324082 DOI: 10.1007/s12975-021-00892-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/18/2020] [Accepted: 01/17/2021] [Indexed: 01/09/2023]
Abstract
Mitochondria can be released by astrocytes as part of a help-me signaling process in stroke. In this study, we investigated the molecular mechanisms that underlie mitochondria secretion, redox status, and functional regulation in the extracellular environment. Exposure of rat primary astrocytes to NAD or cADPR elicited an increase in mitochondrial calcium through ryanodine receptor (RyR) in the endoplasmic reticulum (ER). Importantly, CD38 stimulation with NAD accelerated ATP production along with increasing glutathione reductase (GR) and dipicolinic acid (DPA) in intracellular mitochondria. When RyR was blocked by Dantrolene, all effects were clearly diminished. Mitochondrial functional assay showed that these activated mitochondria appeared to be resistant to H2O2 exposure and sustained mitochondrial membrane potential, while inhibition of RyR resulted in disrupted membrane potential under oxidative stress. Finally, a gain- or loss-of-function assay demonstrated that treatment with DPA in control mitochondria preserved GR contents and increased mitochondrial membrane potential, whereas inhibiting GR with carmustine decreased membrane potentials in extracellular mitochondria released from astrocytes. Collectively, these data suggest that ER-mitochondrial interaction mediated by CD38 stimulation may support mitochondrial energy production and redox homeostasis during the mode of mitochondrial transfer from astrocytes.
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Affiliation(s)
- Ji-Hyun Park
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, 149-2401, Charlestown, MA, 02129, USA
| | - Eng H Lo
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, 149-2401, Charlestown, MA, 02129, USA
| | - Kazuhide Hayakawa
- Neuroprotection Research Laboratory, Departments of Radiology and Neurology, Massachusetts General Hospital and Harvard Medical School, 149-2401, Charlestown, MA, 02129, USA.
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Expression of miR-200c corresponds with increased reactive oxygen species and hypoxia markers after transient focal ischemia in mice. Neurochem Int 2021; 149:105146. [PMID: 34343653 DOI: 10.1016/j.neuint.2021.105146] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 07/24/2021] [Accepted: 07/26/2021] [Indexed: 11/21/2022]
Abstract
Embolic stroke results in a necrotic core of cells destined to die, but also a peri-ischemic, watershed penumbral region of potentially salvageable brain tissue. Approaches to effectively differentiate between the ischemic and peri-ischemic zones is critical for novel therapeutic discovery to improve outcomes in survivors of stroke. MicroRNAs are a class of small non-coding RNAs regulating gene translation that have region- and cell-specific expression and responses to ischemia. We have previously reported that global inhibition of cerebral microRNA-200c after experimental stroke in mice is protective, however delineating the post-stroke sub-regional and cell-type specific patterns of post-stroke miR-200c expression are necessary to minimize off-target effects and advance translational application. Here, we detail a novel protocol to visualize regional miR-200c expression after experimental stroke, complexed with visualization of regional ischemia and markers of oxidative stress in an experimental stroke model in mice. In the present study we demonstrate that the fluorescent hypoxia indicator pimonidazole hydrochloride, the reactive-oxygen-species marker 8-hydroxy-deoxyguanosine, neuronal marker MAP2 and NeuN, and the reactive astrocyte marker GFAP can be effectively complexed to determine regional differences in ischemic injury as early as 30 min post-reperfusion after experimental stroke, and can be effectively used to distinguish ischemic core from surrounding penumbral and unaffected regions for targeted therapy. This multi-dimensional post-stroke immunofluorescent imaging protocol enables a greater degree of sub-regional mechanistic investigation, with the ultimate goal of developing more effective post-stroke pharmaceutical therapy.
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Li G, Li W, Chen J, Zhao S, Bai Z, Liu Q, Liao Q, He M, Zhuang W, Chen M, Sun J, Chen Y. Noninvasive real-time assessment of intracranial pressure after traumatic brain injury based on electromagnetic coupling phase sensing technology. BMC Neurol 2021; 21:26. [PMID: 33455585 PMCID: PMC7812649 DOI: 10.1186/s12883-021-02049-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 01/07/2021] [Indexed: 12/16/2022] Open
Abstract
Background To investigate the feasibility of intracranial pressure (ICP) monitoring after traumatic brain injury (TBI) by electromagnetic coupling phase sensing, we established a portable electromagnetic coupling phase shift (ECPS) test system and conducted a comparison with invasive ICP. Methods TBI rabbits’ model were all synchronously monitored for 24 h by ECPS testing and invasive ICP. We investigated the abilities of the ECPS to detect targeted ICP by feature extraction and traditional classification decision algorithms. Results The ECPS showed an overall downward trend with a variation range of − 13.370 ± 2.245° as ICP rose from 11.450 ± 0.510 mmHg to 38.750 ± 4.064 mmHg, but its change rate gradually declined. It was greater than 1.5°/h during the first 6 h, then decreased to 0.5°/h and finally reached the minimum of 0.14°/h. Nonlinear regression analysis results illustrated that both the ECPS and its change rate decrease with increasing ICP post-TBI. When used as a recognition feature, the ability (area under the receiver operating characteristic curve, AUCs) of the ECPS to detect ICP ≥ 20 mmHg was 0.88 ± 0.01 based on the optimized adaptive boosting model, reaching the advanced level of current noninvasive ICP assessment methods. Conclusions The ECPS has the potential to be used for noninvasive continuous monitoring of elevated ICP post-TBI. Supplementary Information The online version contains supplementary material available at 10.1186/s12883-021-02049-3.
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Affiliation(s)
- Gen Li
- Department of Biomedical Engineering, School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China.,Department of Biomedical Engineering, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing, 400038, China
| | - Wang Li
- Department of Biomedical Engineering, School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China
| | - Jingbo Chen
- Department of Biomedical Engineering, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing, 400038, China
| | - Shuanglin Zhao
- Department of Biomedical Engineering, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing, 400038, China
| | - Zelin Bai
- Department of Biomedical Engineering, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing, 400038, China
| | - Qi Liu
- Department of Biomedical Engineering, School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China
| | - Qi Liao
- Department of Biomedical Engineering, School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing, China
| | - Minglian He
- Department of Neurosurgery, Southwest Hospital, Army Medical University, 29 Gaotanyan Street, Shapingba District, Chongqing, 400038, China.,State Key Laboratory of Trauma, Burn and Combined Injury, Army Medical University, Chongqing, China.,Chongqing Key Laboratory of Precision Neuromedicine and Neuroregenaration, Army Medical University, Chongqing, China
| | - Wei Zhuang
- Department of Biomedical Engineering, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing, 400038, China
| | - Mingsheng Chen
- Department of Biomedical Engineering, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing, 400038, China
| | - Jian Sun
- Department of Biomedical Engineering, Army Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing, 400038, China. .,Department of Neurosurgery, Southwest Hospital, Army Medical University, 29 Gaotanyan Street, Shapingba District, Chongqing, 400038, China. .,State Key Laboratory of Trauma, Burn and Combined Injury, Army Medical University, Chongqing, China. .,Chongqing Key Laboratory of Precision Neuromedicine and Neuroregenaration, Army Medical University, Chongqing, China.
| | - Yujie Chen
- Department of Neurosurgery, Southwest Hospital, Army Medical University, 29 Gaotanyan Street, Shapingba District, Chongqing, 400038, China. .,State Key Laboratory of Trauma, Burn and Combined Injury, Army Medical University, Chongqing, China. .,Chongqing Key Laboratory of Precision Neuromedicine and Neuroregenaration, Army Medical University, Chongqing, China.
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Tang S, Gao P, Chen H, Zhou X, Ou Y, He Y. The Role of Iron, Its Metabolism and Ferroptosis in Traumatic Brain Injury. Front Cell Neurosci 2020; 14:590789. [PMID: 33100976 PMCID: PMC7545318 DOI: 10.3389/fncel.2020.590789] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 09/04/2020] [Indexed: 12/29/2022] Open
Abstract
Traumatic brain injury (TBI) is a structural and physiological disruption of brain function caused by external forces. It is a major cause of death and disability for patients worldwide. TBI includes both primary and secondary impairments. Iron overload and ferroptosis highly involved in the pathophysiological process of secondary brain injury. Ferroptosis is a form of regulatory cell death, as increased iron accumulation in the brain leads to lipid peroxidation, reactive oxygen species (ROS) production, mitochondrial dysfunction and neuroinflammatory responses, resulting in cellular and neuronal damage. For this reason, eliminating factors like iron deposition and inhibiting lipid peroxidation may be a promising therapy. Iron chelators can be used to eliminate excess iron and to alleviate some of the clinical manifestations of TBI. In this review we will focus on the mechanisms of iron and ferroptosis involving the manifestations of TBI, broaden our understanding of the use of iron chelators for TBI. Through this review, we were able to better find novel clinical therapeutic directions for further TBI study.
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Affiliation(s)
- Sicheng Tang
- Medical Clinic and Polyclinic IV, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
| | - Pan Gao
- Department of Translational Neurodegeneration, German Center for Neurodegenerative Diseases (DZNE), Munich, Germany
| | - Hanmin Chen
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiangyue Zhou
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yibo Ou
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yue He
- Department of Neurosurgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Zhou Y, Shao A, Yao Y, Tu S, Deng Y, Zhang J. Dual roles of astrocytes in plasticity and reconstruction after traumatic brain injury. Cell Commun Signal 2020; 18:62. [PMID: 32293472 PMCID: PMC7158016 DOI: 10.1186/s12964-020-00549-2] [Citation(s) in RCA: 100] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 03/06/2020] [Indexed: 12/14/2022] Open
Abstract
Traumatic brain injury (TBI) is one of the leading causes of fatality and disability worldwide. Despite its high prevalence, effective treatment strategies for TBI are limited. Traumatic brain injury induces structural and functional alterations of astrocytes, the most abundant cell type in the brain. As a way of coping with the trauma, astrocytes respond in diverse mechanisms that result in reactive astrogliosis. Astrocytes are involved in the physiopathologic mechanisms of TBI in an extensive and sophisticated manner. Notably, astrocytes have dual roles in TBI, and some astrocyte-derived factors have double and opposite properties. Thus, the suppression or promotion of reactive astrogliosis does not have a substantial curative effect. In contrast, selective stimulation of the beneficial astrocyte-derived molecules and simultaneous attenuation of the deleterious factors based on the spatiotemporal-environment can provide a promising astrocyte-targeting therapeutic strategy. In the current review, we describe for the first time the specific dual roles of astrocytes in neuronal plasticity and reconstruction, including neurogenesis, synaptogenesis, angiogenesis, repair of the blood-brain barrier, and glial scar formation after TBI. We have also classified astrocyte-derived factors depending on their neuroprotective and neurotoxic roles to design more appropriate targeted therapies. Video Abstract
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Affiliation(s)
- Yunxiang Zhou
- Department of Surgical Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, No. 88, Jiefang Road, Zhejiang, 310009, Hangzhou, China
| | - Anwen Shao
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Province, Zhejiang, 310009, Hangzhou, China.
| | - Yihan Yao
- Department of Surgical Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, No. 88, Jiefang Road, Zhejiang, 310009, Hangzhou, China
| | - Sheng Tu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Zhejiang, Hangzhou, China
| | - Yongchuan Deng
- Department of Surgical Oncology, The Second Affiliated Hospital, Zhejiang University School of Medicine, No. 88, Jiefang Road, Zhejiang, 310009, Hangzhou, China
| | - Jianmin Zhang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Province, Zhejiang, 310009, Hangzhou, China
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Yang C, Wang L, Weng W, Wang S, Ma Y, Mao Q, Gao G, Chen R, Feng J. Steered migration and changed morphology of human astrocytes by an applied electric field. Exp Cell Res 2018; 374:282-289. [PMID: 30508512 DOI: 10.1016/j.yexcr.2018.11.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/27/2018] [Accepted: 11/29/2018] [Indexed: 01/01/2023]
Abstract
Direct current electric field (DC EF) plays a role in influencing the biological behaviors and functions of cells. We hypothesize that human astrocytes (HAs) could also be influenced in EF. Astrocytes, an important type of nerve cells with a high proportion quantitatively, are generally activated and largely decide the brain repair results after brain injury. So far, no electrotaxis study on HAs has been performed. We here obtained HAs derived from brain trauma patients. After purification and identification, HAs were seeded in the EF chamber and recorded in a time-lapse image system. LY294002 and U0126 were then used to probe the role of PI3K or ERK signaling pathway on cellular behaviors. The results showed that HAs could be guided to migrate to the anode in DC EFs, in a voltage-dependent manner. The HAs displayed elongated cell bodies and reoriented perpendicularly to the EF in morphology. When treated with LY294002 or U0126, alternation of parameters such as cellular verticality, track speed, displacement speed, long axis, vertical length and circularity were inhibited partly as expected, while the EF-induced directedness was not terminated even at a high drug dosage which was not consistent with previous electrotaxis studies. In conclusion, applied EFs steered the patient-derived HAs directional migration and changed morphology, in which PI3K and ERK pathways at least partially participate. The characteristics of HAs to EF stimulation may be involved in wound healing and neural regeneration, which could be utilized as a novel treatment strategy in brain injury.
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Affiliation(s)
- Chun Yang
- Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, People's Republic of China; Shanghai Institute of Head Trauma, Shanghai 200127, People's Republic of China
| | - Lei Wang
- Department of Neurosurgery, the Yuhuangding Hospital, Yantai 264000, People's Republic of China
| | - Weiji Weng
- Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, People's Republic of China; Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, People's Republic of China
| | - Shen Wang
- Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, People's Republic of China; Shanghai Institute of Head Trauma, Shanghai 200127, People's Republic of China
| | - Yuxiao Ma
- Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, People's Republic of China; Shanghai Institute of Head Trauma, Shanghai 200127, People's Republic of China
| | - Qing Mao
- Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, People's Republic of China; Shanghai Institute of Head Trauma, Shanghai 200127, People's Republic of China
| | - Guoyi Gao
- Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, People's Republic of China
| | - Rui Chen
- Department of Plastic Surgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, People's Republic of China.
| | - Junfeng Feng
- Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200127, People's Republic of China; Shanghai Institute of Head Trauma, Shanghai 200127, People's Republic of China.
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Wei S, Tong J, Xue Q, Liu Y, Xu X. Effect of puerarin on transcriptome of astrocyte during oxygen-glucose deprivation/reoxygenation injury. Mol Cell Biochem 2016; 425:113-123. [PMID: 27844252 DOI: 10.1007/s11010-016-2867-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 11/02/2016] [Indexed: 12/12/2022]
Abstract
Stroke is a serious disease with complex pathomechanism and limited therapeutic effect in clinic. Our previous research has found obvious therapeutic effect of Puerarin (Pur) on stroke injury of rat. The aim of this study is to investigate the transcriptome changes of oxygen-glucose deprivation/reoxygenation (OGD/R)-injured astrocytes before and after the intervention of Pur. Cells activity and apoptosis detection indicated that the activity of OGD/R-injured astrocytes was improved, and the apoptosis was ameliorated by Pur. Affymetrix GeneChip Rat Genome 230 2.0 Array assays indicated that after intervention of Pur, mRNA expressions of 31 genes were up-regulated and 40 genes were down-regulated in OGD group, whereas mRNA expression of 36 genes were up-regulated, and 88 genes were down-regulated in OGD/R group. Pathway analysis indicated that the olfactory transduction pathway and the JAK (janus kinase) 2/STAT (signal transducer and activator of transcription) three pathways were down-regulated by Pur during OGD/R injury of astrocytes. These data indicated that Pur regulates transcriptome and expresses protective effect on astrocytes during OGD/R injury, and may be a potential therapeutic agent for the treatment of stroke.
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Affiliation(s)
- Shuyong Wei
- Southwest University, Rongchang campus, Rongchang, Chongqing, 402460, China.
| | - Jie Tong
- Pharmaceutical Sciences College & Chinese Medicine College, Southwest University, Chongqing Engineering Research Center for Pharmacodynamics Evaluation, Chongqing, 400716, China
| | - Qiang Xue
- Pharmaceutical Sciences College & Chinese Medicine College, Southwest University, Chongqing Engineering Research Center for Pharmacodynamics Evaluation, Chongqing, 400716, China
| | - Yang Liu
- Pharmaceutical Sciences College & Chinese Medicine College, Southwest University, Chongqing Engineering Research Center for Pharmacodynamics Evaluation, Chongqing, 400716, China
| | - Xiaoyu Xu
- Pharmaceutical Sciences College & Chinese Medicine College, Southwest University, Chongqing Engineering Research Center for Pharmacodynamics Evaluation, Chongqing, 400716, China.
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Targeting Glial Mitochondrial Function for Protection from Cerebral Ischemia: Relevance, Mechanisms, and the Role of MicroRNAs. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:6032306. [PMID: 27777645 PMCID: PMC5061974 DOI: 10.1155/2016/6032306] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 08/21/2016] [Accepted: 08/31/2016] [Indexed: 12/11/2022]
Abstract
Astrocytes and microglia play crucial roles in the response to cerebral ischemia and are effective targets for stroke therapy in animal models. MicroRNAs (miRs) are important posttranscriptional regulators of gene expression that function by inhibiting the translation of select target genes. In astrocytes, miR expression patterns regulate mitochondrial function in response to oxidative stress via targeting of Bcl2 and heat shock protein 70 family members. Mitochondria play an active role in microglial activation, and miRs regulate the microglial neuroinflammatory response. As endogenous miR expression patterns can be altered with exogenous mimics and inhibitors, miR-targeted therapies represent a viable intervention to optimize glial mitochondrial function and improve clinical outcome following cerebral ischemia. In the present article, we review the role that astrocytes and microglia play in neuronal function and fate following ischemic stress, discuss the relevance of mitochondria in the glial response to injury, and present current evidence implicating miRs as critical regulators in the glial mitochondrial response to cerebral ischemia.
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Nikolakopoulou AM, Koeppen J, Garcia M, Leish J, Obenaus A, Ethell IM. Astrocytic Ephrin-B1 Regulates Synapse Remodeling Following Traumatic Brain Injury. ASN Neuro 2016; 8:1-18. [PMID: 26928051 PMCID: PMC4774052 DOI: 10.1177/1759091416630220] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 12/31/2015] [Indexed: 01/06/2023] Open
Abstract
Traumatic brain injury (TBI) can result in tissue alterations distant from the site of the initial injury, which can trigger pathological changes within hippocampal circuits and are thought to contribute to long-term cognitive and neuropsychological impairments. However, our understanding of secondary injury mechanisms is limited. Astrocytes play an important role in brain repair after injury and astrocyte-mediated mechanisms that are implicated in synapse development are likely important in injury-induced synapse remodeling. Our studies suggest a new role of ephrin-B1, which is known to regulate synapse development in neurons, in astrocyte-mediated synapse remodeling following TBI. Indeed, we observed a transient upregulation of ephrin-B1 immunoreactivity in hippocampal astrocytes following moderate controlled cortical impact model of TBI. The upregulation of ephrin-B1 levels in hippocampal astrocytes coincided with a decline in the number of vGlut1-positive glutamatergic input to CA1 neurons at 3 days post injury even in the absence of hippocampal neuron loss. In contrast, tamoxifen-induced ablation of ephrin-B1 from adult astrocytes in ephrin-B1loxP/yERT2-CreGFAP mice accelerated the recovery of vGlut1-positive glutamatergic input to CA1 neurons after TBI. Finally, our studies suggest that astrocytic ephrin-B1 may play an active role in injury-induced synapse remodeling through the activation of STAT3-mediated signaling in astrocytes. TBI-induced upregulation of STAT3 phosphorylation within the hippocampus was suppressed by astrocyte-specific ablation of ephrin-B1 in vivo, whereas the activation of ephrin-B1 in astrocytes triggered an increase in STAT3 phosphorylation in vitro. Thus, regulation of ephrin-B1 signaling in astrocytes may provide new therapeutic opportunities to aid functional recovery after TBI.
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Affiliation(s)
| | - Jordan Koeppen
- Biomedical Sciences Division, School of Medicine, University of California Riverside, CA, USA Cell, Molecular, and Developmental Biology graduate program, University of California Riverside, CA, USA
| | - Michael Garcia
- Biomedical Sciences Division, School of Medicine, University of California Riverside, CA, USA
| | - Joshua Leish
- Biomedical Sciences Division, School of Medicine, University of California Riverside, CA, USA
| | - Andre Obenaus
- Department of Pediatrics, School of Medicine, Loma Linda University, CA, USA
| | - Iryna M Ethell
- Biomedical Sciences Division, School of Medicine, University of California Riverside, CA, USA Cell, Molecular, and Developmental Biology graduate program, University of California Riverside, CA, USA
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Astrocytes Protect against Isoflurane Neurotoxicity by Buffering pro-brain-derived Neurotrophic Factor. Anesthesiology 2015; 123:810-9. [PMID: 26270940 DOI: 10.1097/aln.0000000000000824] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Isoflurane induces cell death in neurons undergoing synaptogenesis via increased production of pro-brain-derived neurotrophic factor (proBDNF) and activation of postsynaptic p75 neurotrophin receptor (p75). Astrocytes express p75, but their role in neuronal p75-mediated cell death remains unclear. The authors investigated whether astrocytes have the capacity to buffer increases in proBDNF and protect against isoflurane/p75 neurotoxicity. METHODS Cell death was assessed in day in vitro (DIV) 7 mouse primary neuronal cultures alone or in co-culture with age-matched or DIV 21 astrocytes with propidium iodide 24 h after 1 h exposure to 2% isoflurane or recombinant proBDNF. Astrocyte-targeted knockdown of p75 in co-culture was achieved with small-interfering RNA and astrocyte-specific transfection reagent and verified with immunofluorescence microscopy. proBDNF levels were assessed by enzyme-linked immunosorbent assay. Each experiment used six to eight replicate cultures/condition and was repeated at least three times. RESULTS Exposure to isoflurane significantly (P < 0.05) increased neuronal cell death in primary neuronal cultures (1.5 ± 0.7 fold, mean ± SD) but not in co-culture with DIV 7 (1.0 ± 0.5 fold) or DIV 21 astrocytes (1.2 ± 1.2 fold). Exogenous proBDNF dose dependently induced neuronal cell death in both primary neuronal and co-cultures, an effect enhanced by astrocyte p75 inhibition. Astrocyte-targeted p75 knockdown in co-cultures increased media proBDNF (1.2 ± 0.1 fold) and augmented isoflurane-induced neuronal cell death (3.8 ± 3.1 fold). CONCLUSIONS The presence of astrocytes provides protection to growing neurons by buffering increased levels of proBDNF induced by isoflurane. These findings may hold clinical significance for the neonatal and injured brain where increased levels of proBDNF impair neurogenesis.
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Lok J, Wang XS, Xing CH, Maki TK, Wu LM, Guo SZ, Noviski N, Arai K, Whalen MJ, Lo EH, Wang XY. Targeting the neurovascular unit in brain trauma. CNS Neurosci Ther 2014; 21:304-8. [PMID: 25475543 DOI: 10.1111/cns.12359] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/24/2014] [Accepted: 10/26/2014] [Indexed: 01/22/2023] Open
Abstract
Although the neurovascular unit was originally developed as a conceptual framework for stroke, it is now recognized that these cell-cell interactions play critical roles in many other CNS disorders as well. In brain trauma, perturbations within the neurovascular unit may be especially important. Changes in neurovascular coupling may disrupt blood flow and metabolic regulation. Disruption of transmitter release-reuptake kinetics in neurons and astrocytes may augment excitotoxicity. Alterations in gliovascular signaling may underlie blood-brain barrier disruptions and traumatic edema. Perturbations in cell-cell signaling between all neuronal, glial, and vascular compartments may increase susceptibility to cell death. Finally, repairing the brain after trauma requires the integrated restoration of all neural, glial, and vascular connectivity for effective functional recovery. Just as in stroke, saving neurons alone may also be insufficient for treating brain trauma. In this minireview, we attempt to briefly highlight some of these pathways to underscore the importance of rescuing the entire neurovascular unit in brain trauma.
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Affiliation(s)
- Josephine Lok
- Departments of Radiology, Neurology and Pediatrics, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
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Michinaga S, Nagase M, Matsuyama E, Yamanaka D, Seno N, Fuka M, Yamamoto Y, Koyama Y. Amelioration of cold injury-induced cortical brain edema formation by selective endothelin ETB receptor antagonists in mice. PLoS One 2014; 9:e102009. [PMID: 25000290 PMCID: PMC4084986 DOI: 10.1371/journal.pone.0102009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 06/13/2014] [Indexed: 12/13/2022] Open
Abstract
Brain edema is a potentially fatal pathological condition that often occurs in stroke and head trauma. Following brain insults, endothelins (ETs) are increased and promote several pathophysiological responses. This study examined the effects of ETB antagonists on brain edema formation and disruption of the blood-brain barrier in a mouse cold injury model (Five- to six-week-old male ddY mice). Cold injury increased the water content of the injured cerebrum, and promoted extravasation of both Evans blue and endogenous albumin. In the injury area, expression of prepro-ET-1 mRNA and ET-1 peptide increased. Intracerebroventricular (ICV) administration of BQ788 (ETB antagonist), IRL-2500 (ETB antagonist), or FR139317 (ETA antagonist) prior to cold injury significantly attenuated the increase in brain water content. Bolus administration of BQ788, IRL-2500, or FR139317 also inhibited the cold injury-induced extravasation of Evans blue and albumin. Repeated administration of BQ788 and IRL-2500 beginning at 24 h after cold injury attenuated both the increase in brain water content and extravasation of markers. In contrast, FR139317 had no effect on edema formation when administrated after cold injury. Cold injury stimulated induction of glial fibrillary acidic protein-positive reactive astrocytes in the injured cerebrum. Induction of reactive astrocytes after cold injury was attenuated by ICV administration of BQ788 or IRL-2500. These results suggest that ETB receptor antagonists may be an effective approach to ameliorate brain edema formation following brain insults.
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Affiliation(s)
- Shotaro Michinaga
- Laboratory of Pharmacology, Faculty of Pharmacy, Osaka Ohtani University, Tonda-bayashi, Osaka, Japan
| | - Marina Nagase
- Laboratory of Pharmacology, Faculty of Pharmacy, Osaka Ohtani University, Tonda-bayashi, Osaka, Japan
| | - Emi Matsuyama
- Laboratory of Pharmacology, Faculty of Pharmacy, Osaka Ohtani University, Tonda-bayashi, Osaka, Japan
| | - Daisuke Yamanaka
- Laboratory of Pharmacology, Faculty of Pharmacy, Osaka Ohtani University, Tonda-bayashi, Osaka, Japan
| | - Naoki Seno
- Laboratory of Pharmacology, Faculty of Pharmacy, Osaka Ohtani University, Tonda-bayashi, Osaka, Japan
| | - Mayu Fuka
- Laboratory of Pharmacology, Faculty of Pharmacy, Osaka Ohtani University, Tonda-bayashi, Osaka, Japan
| | - Yui Yamamoto
- Laboratory of Pharmacology, Faculty of Pharmacy, Osaka Ohtani University, Tonda-bayashi, Osaka, Japan
| | - Yutaka Koyama
- Laboratory of Pharmacology, Faculty of Pharmacy, Osaka Ohtani University, Tonda-bayashi, Osaka, Japan
- * E-mail:
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Translational research in neurotrauma: novel mechanisms and emerging therapies. Transl Stroke Res 2011; 2:425-6. [PMID: 24323677 DOI: 10.1007/s12975-011-0135-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2011] [Revised: 10/29/2011] [Accepted: 10/29/2011] [Indexed: 10/15/2022]
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