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Santos AB, Carona A, Ettcheto M, Camins A, Falcão A, Fortuna A, Bicker J. Krüppel-like factors: potential roles in blood-brain barrier dysfunction and epileptogenesis. Acta Pharmacol Sin 2024:10.1038/s41401-024-01285-w. [PMID: 38684799 DOI: 10.1038/s41401-024-01285-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 04/07/2024] [Indexed: 05/02/2024] Open
Abstract
Epilepsy is a chronic and debilitating neurological disorder, known for the occurrence of spontaneous and recurrent seizures. Despite the availability of antiseizure drugs, 30% of people with epilepsy experience uncontrolled seizures and drug resistance, evidencing that new therapeutic options are required. The process of epileptogenesis involves the development and expansion of tissue capable of generating spontaneous recurrent seizures, during which numerous events take place, namely blood-brain barrier (BBB) dysfunction, and neuroinflammation. The consequent cerebrovascular dysfunction results in a lower seizure threshold, seizure recurrence, and chronic epilepsy. This suggests that improving cerebrovascular health may interrupt the pathological cycle responsible for disease development and progression. Krüppel-like factors (KLFs) are a family of zinc-finger transcription factors, encountered in brain endothelial cells, glial cells, and neurons. KLFs are known to regulate vascular function and changes in their expression are associated with neuroinflammation and human diseases, including epilepsy. Hence, KLFs have demonstrated various roles in cerebrovascular dysfunction and epileptogenesis. This review critically discusses the purpose of KLFs in epileptogenic mechanisms and BBB dysfunction, as well as the potential of their pharmacological modulation as therapeutic approach for epilepsy treatment.
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Affiliation(s)
| | - Andreia Carona
- University of Coimbra, Faculty of Pharmacy, Coimbra, Portugal
- University of Coimbra, Coimbra Institute for Biomedical Imaging and Translational Research, Coimbra, Portugal
| | - Miren Ettcheto
- Biomedical Research Networking Center in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Science, Universitat de Barcelona, Barcelona, Spain
- Institute of Neuroscience, Universitat de Barcelona, Barcelona, Spain
- Institut d'Investigació Sanitària Pere Virgili (IISPV), Reus, Spain
| | - Antoni Camins
- Biomedical Research Networking Center in Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Pharmacology, Toxicology and Therapeutic Chemistry, Faculty of Pharmacy and Food Science, Universitat de Barcelona, Barcelona, Spain
- Institute of Neuroscience, Universitat de Barcelona, Barcelona, Spain
- Institut d'Investigació Sanitària Pere Virgili (IISPV), Reus, Spain
| | - Amílcar Falcão
- University of Coimbra, Faculty of Pharmacy, Coimbra, Portugal
- University of Coimbra, Coimbra Institute for Biomedical Imaging and Translational Research, Coimbra, Portugal
| | - Ana Fortuna
- University of Coimbra, Faculty of Pharmacy, Coimbra, Portugal
- University of Coimbra, Coimbra Institute for Biomedical Imaging and Translational Research, Coimbra, Portugal
| | - Joana Bicker
- University of Coimbra, Faculty of Pharmacy, Coimbra, Portugal.
- University of Coimbra, Coimbra Institute for Biomedical Imaging and Translational Research, Coimbra, Portugal.
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2
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Choi IY, Cha JH, Kim SY, Hsieh J, Cho KO. Seizure-induced LIN28A disrupts pattern separation via aberrant hippocampal neurogenesis. JCI Insight 2024; 9:e175627. [PMID: 38193536 PMCID: PMC10906464 DOI: 10.1172/jci.insight.175627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 11/15/2023] [Indexed: 01/10/2024] Open
Abstract
Prolonged seizures can disrupt stem cell behavior in the adult hippocampus, an important brain structure for spatial memory. Here, using a mouse model of pilocarpine-induced status epilepticus (SE), we characterized spatiotemporal expression of Lin28a mRNA and proteins after SE. Unlike Lin28a transcripts, induction of LIN28A protein after SE was detected mainly in the subgranular zone, where immunoreactivity was found in progenitors, neuroblasts, and immature and mature granule neurons. To investigate roles of LIN28A in epilepsy, we generated Nestin-Cre:Lin28aloxP/loxP (conditional KO [cKO]) and Nestin-Cre:Lin28a+/+ (WT) mice to block LIN28A upregulation in all neuronal lineages after acute seizure. Adult-generated neuron- and hippocampus-associated cognitive impairments were absent in epileptic LIN28A-cKO mice, as evaluated by pattern separation and contextual fear conditioning tests, respectively, while sham-manipulated WT and cKO animals showed comparable memory function. Moreover, numbers of hilar PROX1-expressing ectopic granule cells (EGCs), together with PROX1+/NEUN+ mature EGCs, were significantly reduced in epileptic cKO mice. Transcriptomics analysis and IHC validation at 3 days after pilocarpine administration provided potential LIN28A downstream targets such as serotonin receptor 4. Collectively, our findings indicate that LIN28A is a potentially novel target for regulation of newborn neuron-associated memory dysfunction in epilepsy by modulating seizure-induced aberrant neurogenesis.
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Affiliation(s)
| | | | - Seong Yun Kim
- Department of Pharmacology, College of Medicine
- Department of Biomedicine & Health Sciences, and
- Catholic Neuroscience Institute, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jenny Hsieh
- Department of Neuroscience, Developmental and Regenerative Biology, and
- Brain Health Consortium, The University of Texas at San Antonio, San Antonio, Texas, USA
| | - Kyung-Ok Cho
- Department of Pharmacology, College of Medicine
- Department of Biomedicine & Health Sciences, and
- Catholic Neuroscience Institute, The Catholic University of Korea, Seoul, Republic of Korea
- Institute for Aging and Metabolic Diseases and
- CMC Institute for Basic Medical Science, the Catholic Medical Center of The Catholic University of Korea, Seoul, Republic of Korea
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3
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Roh Y, Lee SB, Kim M, Kim MH, Kim HJ, Cho KO. Alleviation of hippocampal necroptosis and neuroinflammation by NecroX-7 treatment after acute seizures. Front Pharmacol 2023; 14:1187819. [PMID: 37601059 PMCID: PMC10433749 DOI: 10.3389/fphar.2023.1187819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 07/24/2023] [Indexed: 08/22/2023] Open
Abstract
Temporal lobe epilepsy (TLE) is one of the most common neurological disorders, but still one-third of patients cannot be properly treated by current medication. Thus, we investigated the therapeutic effects of a novel small molecule, NecroX-7, in TLE using both a low [Mg2+]o-induced epileptiform activity model and a mouse model of pilocarpine-induced status epilepticus (SE). NecroX-7 post-treatment enhanced the viability of primary hippocampal neurons exposed to low [Mg2+]o compared to controls in an MTT assay. Application of NecroX-7 after pilocarpine-induced SE also reduced the number of degenerating neurons labelled with Fluoro-Jade B. Immunocytochemistry and immunohistochemistry showed that NecroX-7 post-treatment significantly alleviated ionized calcium-binding adaptor molecule 1 (Iba1) intensity and immunoreactive area, while the attenuation of reactive astrocytosis by glial fibrillary acidic protein (GFAP) staining was observed in cultured hippocampal neurons. However, NecroX-7-mediated morphologic changes of astrocytes were seen in both in vitro and in vivo models of TLE. Finally, western blot analysis demonstrated that NecroX-7 post-treatment after acute seizures could decrease the expression of mixed lineage kinase domain-like pseudokinase (MLKL) and phosphorylated MLKL (p-MLKL), markers for necroptosis. Taken all together, NecroX-7 has potential as a novel medication for TLE with its neuroprotective, anti-inflammatory, and anti-necroptotic effects.
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Affiliation(s)
- Yihyun Roh
- College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Su Bin Lee
- Department of Medical Laser, Graduate School, Dankook University, Cheonan, Republic of Korea
| | - Minseo Kim
- College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Mi-Hye Kim
- Department of Medical Laser, Graduate School, Dankook University, Cheonan, Republic of Korea
| | - Hee Jung Kim
- Department of Physiology, College of Medicine, Center for Human Risk Assessment, Dankook University, Cheonan, Republic of Korea
| | - Kyung-Ok Cho
- Department of Pharmacology, Catholic Neuroscience Institute, Institute for Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- Department of Biomedicine and Health Sciences, The Catholic University of Korea, Seoul, Republic of Korea
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4
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Choi IY, Cho ML, Cho KO. Interleukin-17A Mediates Hippocampal Damage and Aberrant Neurogenesis Contributing to Epilepsy-Associated Anxiety. Front Mol Neurosci 2022; 15:917598. [PMID: 35875667 PMCID: PMC9298510 DOI: 10.3389/fnmol.2022.917598] [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] [Received: 04/11/2022] [Accepted: 06/07/2022] [Indexed: 11/23/2022] Open
Abstract
Anxiety disorder is one of the most common comorbidities in temporal lobe epilepsy (TLE), but its neurobiological mechanisms remain unclear. Here we identified a novel target, interleukin-17A (IL-17A), which can contribute to TLE-associated anxiety. Epileptic seizures were induced in 6-week-old IL-17A wild-type (WT) and knockout (KO) mice by pilocarpine injection. To evaluate anxiety level, we subjected mice to open field and elevated plus maze (EPM) tests and measured the time animals spent in center zone or open arms. Epileptic IL-17A WT mice showed thigmotaxis and reluctance to stay in open arms, whereas IL-17A KO mice spent more time in the center area and open arms, suggesting alleviated anxiety in epilepsy. Histological assessments revealed that hippocampal neuronal death as evaluated by Fluoro-Jade B staining was significantly reduced in IL-17A KO mice. Moreover, at 6 weeks after pilocarpine-induced status epilepticus, the number of hilar ectopic granule cells was also markedly decreased by IL-17A deficiency without a difference in the proliferation of neural progenitors or the generation of newborn neurons in the dentate gyrus. Taken together, our data demonstrated that IL-17A deletion mitigates TLE-associated anxiety behavior, possibly via the hippocampal neuroprotection and the reduction of seizure-induced aberrant neurogenesis.
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Affiliation(s)
- In-Young Choi
- Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul, South Korea
| | - Mi-La Cho
- Department of Medical Life Science, College of Medicine, The Catholic University of Korea, Seoul, South Korea.,Department of Biomedicine and Health Sciences, The Catholic University of Korea, Seoul, South Korea
| | - Kyung-Ok Cho
- Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul, South Korea.,Department of Biomedicine and Health Sciences, The Catholic University of Korea, Seoul, South Korea.,Catholic Neuroscience Institute, The Catholic University of Korea, Seoul, South Korea.,Institute for Aging and Metabolic Diseases, The Catholic University of Korea, Seoul, South Korea
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5
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Burda JE, O'Shea TM, Ao Y, Suresh KB, Wang S, Bernstein AM, Chandra A, Deverasetty S, Kawaguchi R, Kim JH, McCallum S, Rogers A, Wahane S, Sofroniew MV. Divergent transcriptional regulation of astrocyte reactivity across disorders. Nature 2022; 606:557-564. [PMID: 35614216 PMCID: PMC10027402 DOI: 10.1038/s41586-022-04739-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 04/07/2022] [Indexed: 01/30/2023]
Abstract
Astrocytes respond to injury and disease in the central nervous system with reactive changes that influence the outcome of the disorder1-4. These changes include differentially expressed genes (DEGs) whose contextual diversity and regulation are poorly understood. Here we combined biological and informatic analyses, including RNA sequencing, protein detection, assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and conditional gene deletion, to predict transcriptional regulators that differentially control more than 12,000 DEGs that are potentially associated with astrocyte reactivity across diverse central nervous system disorders in mice and humans. DEGs associated with astrocyte reactivity exhibited pronounced heterogeneity across disorders. Transcriptional regulators also exhibited disorder-specific differences, but a core group of 61 transcriptional regulators was identified as common across multiple disorders in both species. We show experimentally that DEG diversity is determined by combinatorial, context-specific interactions between transcriptional regulators. Notably, the same reactivity transcriptional regulators can regulate markedly different DEG cohorts in different disorders; changes in the access of transcriptional regulators to DNA-binding motifs differ markedly across disorders; and DEG changes can crucially require multiple reactivity transcriptional regulators. We show that, by modulating reactivity, transcriptional regulators can substantially alter disorder outcome, implicating them as therapeutic targets. We provide searchable resources of disorder-related reactive astrocyte DEGs and their predicted transcriptional regulators. Our findings show that transcriptional changes associated with astrocyte reactivity are highly heterogeneous and are customized from vast numbers of potential DEGs through context-specific combinatorial transcriptional-regulator interactions.
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Affiliation(s)
- Joshua E Burda
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
- Center for Neural Science and Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
| | - Timothy M O'Shea
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Yan Ao
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Keshav B Suresh
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Center for Neural Science and Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Shinong Wang
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Alexander M Bernstein
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Ashu Chandra
- Department of Computer Science, University of California Los Angeles, Los Angeles, CA, USA
| | - Sandeep Deverasetty
- Department of Psychiatry, University of California Los Angeles, Los Angeles, CA, USA
- Department of Neurology, University of California Los Angeles, Los Angeles, CA, USA
| | - Riki Kawaguchi
- Department of Psychiatry, University of California Los Angeles, Los Angeles, CA, USA
- Department of Neurology, University of California Los Angeles, Los Angeles, CA, USA
| | - Jae H Kim
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Sarah McCallum
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Center for Neural Science and Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Alexandra Rogers
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Shalaka Wahane
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Michael V Sofroniew
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
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6
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Choi IY, Shim JH, Kim MH, Yu WD, Kim YJ, Choi G, Lee JH, Kim HJ, Cho KO. Truncated Neogenin Promotes Hippocampal Neuronal Death after Acute Seizure. Neuroscience 2021; 470:78-87. [PMID: 34245840 DOI: 10.1016/j.neuroscience.2021.06.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 06/04/2021] [Accepted: 06/30/2021] [Indexed: 01/13/2023]
Abstract
Protecting hippocampal neurons from death after seizure activity is critical to prevent an alteration of neuronal circuitry and hippocampal function. Here, we present a novel target, a truncated form of neogenin that is associated with seizure-induced hippocampal necroptosis, and novel use of the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) as a pharmacological regulator of neogenin truncation. We show that 3 days after pilocarpine-induced status epilepticus in mice, when hippocampal cell death is detected, the level of truncated neogenin is increased, while that of full-length neogenin is decreased. Moreover, phosphorylation of mixed lineage kinase domain-like pseudokinase, a crucial marker of necroptosis, was also markedly upregulated at 3 days post-status epilepticus. In cultured hippocampal cells, kainic acid treatment significantly reduced the expression of full-length neogenin. Notably, treatment with DAPT prevented neogenin truncation and protected cultured neurons from N-methyl-D-aspartate (NMDA)-induced death. These data suggest that seizure-induced hippocampal necroptosis is associated with the generation of truncated neogenin, and that prevention of this by DAPT treatment can protect against NMDA-induced excitotoxicity.
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Affiliation(s)
- In-Young Choi
- Department of Pharmacology, Department of Biomedicine & Health Sciences, Catholic Neuroscience Institute, Institute of Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jae Hyuk Shim
- Department of Physiology, College of Medicine, Dankook University, Cheonan, Republic of Korea; Department of Medical Laser, Graduate School, Dankook University, Cheonan, Republic of Korea
| | - Mi-Hye Kim
- Department of Physiology, College of Medicine, Dankook University, Cheonan, Republic of Korea; Department of Medical Laser, Graduate School, Dankook University, Cheonan, Republic of Korea
| | - Won Dong Yu
- Department of Biomedical Science, College of Life Science, CHA University, Pocheon, Republic of Korea
| | - Yu Jin Kim
- Department of Biomedical Science, College of Life Science, CHA University, Pocheon, Republic of Korea
| | - Gain Choi
- Department of Physiology, College of Medicine, Dankook University, Cheonan, Republic of Korea; Department of Medical Laser, Graduate School, Dankook University, Cheonan, Republic of Korea
| | - Jae Ho Lee
- Department of Biomedical Science, College of Life Science, CHA University, Pocheon, Republic of Korea.
| | - Hee Jung Kim
- Department of Physiology, College of Medicine, Dankook University, Cheonan, Republic of Korea.
| | - Kyung-Ok Cho
- Department of Pharmacology, Department of Biomedicine & Health Sciences, Catholic Neuroscience Institute, Institute of Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
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7
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Sun J, Cai J, Chen J, Li S, Liao X, He Y, Chen X, Hu S. Krüppel-Like Factor 6 Silencing Prevents Oxidative Stress and Neurological Dysfunction Following Intracerebral Hemorrhage via Sirtuin 5/Nrf2/HO-1 Axis. Front Aging Neurosci 2021; 13:646729. [PMID: 34149393 PMCID: PMC8209425 DOI: 10.3389/fnagi.2021.646729] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 03/11/2021] [Indexed: 11/13/2022] Open
Abstract
As a severe neurological deficit, intracerebral hemorrhage (ICH) is associated with overwhelming mortality. Subsequent oxidative stress and neurological dysfunction are likely to cause secondary brain injury. Therefore, this study sought to define the role of Krüppel-like factor 6 (KLF6) and underlying mechanism in oxidative stress and neurological dysfunction following ICH. An in vivo model of ICH was established in rats by injection of autologous blood, and an in vitro ICH cell model was developed in hippocampal neurons by oxyhemoglobin (OxyHb) exposure. Next, gain- and loss-of-function assays were performed in vivo and in vitro to clarify the effect of KLF6 on neurological dysfunction and oxidative stress in ICH rats and neuronal apoptosis and mitochondrial reactive oxygen species in OxyHb-induced hippocampal neurons. KLF6, nuclear factor erythroid 2–related factor 2 (Nrf2), and heme oxygenase 1 (HO-1) were highly expressed in hippocampal tissues of ICH rats, whereas sirtuin 5 (SIRT5) presented a poor expression. Mechanistically, KLF6 bound to the SIRT5 promoter and transcriptionally repressed SIRT5 to activate the Nrf2/HO-1 signaling pathway. KLF6 silencing alleviated neurological dysfunction and oxidative stress in ICH rats and diminished oxidative stress and neuronal apoptosis in OxyHb-induced neurons, whereas SIRT5 overexpression negated its effect. To sum up, KLF6 silencing elevated SIRT5 expression to inactivate the Nrf2/HO-1 signaling pathway, thus attenuating oxidative stress and neurological dysfunction after ICH.
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Affiliation(s)
- Jia Sun
- Shenzhen Beike Biotechnology Research Institute, Shenzhen, China.,Intervention and Cell Therapy Center, Shenzhen Hospital of Peking University, Shenzhen, China
| | - Jinzhong Cai
- Department of Interventional Radiology, Second Clinical Medical College of Jinan University (Shenzhen People's Hospital), Shenzhen, China
| | - Junhui Chen
- Intervention and Cell Therapy Center, Shenzhen Hospital of Peking University, Shenzhen, China
| | - Siqiaozhi Li
- Shenzhen Beike Biotechnology Research Institute, Shenzhen, China
| | - Xin Liao
- Shenzhen Beike Biotechnology Research Institute, Shenzhen, China
| | - Yixuan He
- Shenzhen Beike Biotechnology Research Institute, Shenzhen, China
| | - Xudong Chen
- Department of Interventional Radiology, Second Clinical Medical College of Jinan University (Shenzhen People's Hospital), Shenzhen, China
| | - Sean Hu
- Shenzhen Beike Biotechnology Research Institute, Shenzhen, China
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8
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Cho KO, Jeong KH, Cha JH, Kim SY. Spatiotemporal expression of RCAN1 and its isoform RCAN1-4 in the mouse hippocampus after pilocarpine-induced status epilepticus. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2020; 24:81-88. [PMID: 31908577 PMCID: PMC6940495 DOI: 10.4196/kjpp.2020.24.1.81] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 10/17/2019] [Accepted: 11/22/2019] [Indexed: 11/15/2022]
Abstract
Regulator of calcineurin 1 (RCAN1) can be induced by an intracellular calcium increase and oxidative stress, which are characteristic features of temporal lobe epilepsy. Thus, we investigated the spatiotemporal expression and cellular localization of RCAN1 protein and mRNA in the mouse hippocampus after pilocarpine-induced status epilepticus (SE). Male C57BL/6 mice were given pilocarpine hydrochloride (280 mg/kg, i.p.) and allowed to develop 2 h of SE. Then the animals were given diazepam (10 mg/kg, i.p.) to stop the seizures and sacrificed at 1, 3, 7, 14, or 28 day after SE. Cresyl violet staining showed that pilocarpine-induced SE resulted in cell death in the CA1 and CA3 subfields of the hippocampus from 3 day after SE. RCAN1 immunoreactivity showed that RCAN1 was mainly expressed in neurons in the shammanipulated hippocampi. At 1 day after SE, RCAN1 expression became detected in hippocampal neuropils. However, RCAN1 signals were markedly enhanced in cells with stellate morphology at 3 and 7 day after SE, which were confirmed to be reactive astrocytes, but not microglia by double immunofluorescence. In addition, real-time reverse transcriptase–polymerase chain reaction showed a significant upregulation of RCAN1 isoform 4 (RCAN1-4) mRNA in the SE-induced hippocampi. Finally, in situ hybridization with immunohistochemistry revealed astrocytic expression of RCAN1-4 after SE. These results demonstrate astrocytic upregulation of RCAN1 and RCAN1-4 in the mouse hippocampus in the acute and subacute phases of epileptogenesis, providing foundational information for the potential role of RCAN1 in reactive astrocytes during epileptogenesis.
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Affiliation(s)
- Kyung-Ok Cho
- Department of Pharmacology, Department of Biomedicine & Health Sciences, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.,Institute of Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Kyoung Hoon Jeong
- Department of Pharmacology, Department of Biomedicine & Health Sciences, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Jung-Ho Cha
- Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Seong Yun Kim
- Department of Pharmacology, Department of Biomedicine & Health Sciences, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
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9
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Jeong KH, Cho KO, Lee MY, Kim SY, Kim WJ. Vascular endothelial growth factor receptor-3 regulates astroglial glutamate transporter-1 expression via mTOR activation in reactive astrocytes following pilocarpine-induced status epilepticus. Glia 2020; 69:296-309. [PMID: 32835451 DOI: 10.1002/glia.23897] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 07/19/2020] [Accepted: 07/22/2020] [Indexed: 12/13/2022]
Abstract
Recent evidence has shown that the vascular endothelial growth factor (VEGF) system plays a crucial role in several neuropathological processes. We previously reported an upregulation of VEGF-C and its receptor, VEGFR-3, in reactive astrocytes after the onset of status epilepticus (SE). However, it remains unknown, which molecules act as downstream signals following VEGFR-3 upregulation, and are involved in reactive astrogliosis after SE. Therefore, we investigated whether VEGFR-3 upregulation within reactive astrocytes is associated with the activation of mammalian target of rapamycin (mTOR) signaling, which we confirmed by assaying for the phosphorylated form of S6 protein (pS6), and whether VEGFR-3-mediated mTOR activation induces astroglial glutamate transporter-1 (GLT-1) expression in the hippocampus after pilocarpine-induced SE. We found that spatiotemporal expression of pS6 was consistent with VEGFR-3 expression in the hippocampus after SE, and that both pS6 and VEGFR-3 were highly expressed in SE-induced reactive astrocytes. Treatment with the mTOR inhibitor rapamycin decreased astroglial VEGFR-3 expression and GLT-1 expression after SE. Treatment with a selective inhibitor for VEGFR-3 attenuated astroglial pS6 expression as well as suppressed GLT-1 expression and astroglial reactivity in the hippocampus after SE. These findings demonstrate that VEGFR-3-mediated mTOR activation could contribute to the regulation of GLT-1 expression in reactive astrocytes during the subacute phase of epilepsy. In conclusion, the present study suggests that VEGFR-3 upregulation in reactive astrocytes may play a role in preventing hyperexcitability induced by continued seizure activity.
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Affiliation(s)
- Kyoung Hoon Jeong
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea.,Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Kyung-Ok Cho
- Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Mun-Yong Lee
- Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Seong Yun Kim
- Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.,Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seoul, Republic of Korea.,Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Won-Joo Kim
- Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea
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10
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Comparison of different input modalities and network structures for deep learning-based seizure detection. Sci Rep 2020; 10:122. [PMID: 31924842 PMCID: PMC6954227 DOI: 10.1038/s41598-019-56958-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 12/16/2019] [Indexed: 02/07/2023] Open
Abstract
The manual review of an electroencephalogram (EEG) for seizure detection is a laborious and error-prone process. Thus, automated seizure detection based on machine learning has been studied for decades. Recently, deep learning has been adopted in order to avoid manual feature extraction and selection. In the present study, we systematically compared the performance of different combinations of input modalities and network structures on a fixed window size and dataset to ascertain an optimal combination of input modalities and network structures. The raw time-series EEG, periodogram of the EEG, 2D images of short-time Fourier transform results, and 2D images of raw EEG waveforms were obtained from 5-s segments of intracranial EEGs recorded from a mouse model of epilepsy. A fully connected neural network (FCNN), recurrent neural network (RNN), and convolutional neural network (CNN) were implemented to classify the various inputs. The classification results for the test dataset showed that CNN performed better than FCNN and RNN, with the area under the curve (AUC) for the receiver operating characteristics curves ranging from 0.983 to 0.984, from 0.985 to 0.989, and from 0.989 to 0.993 for FCNN, RNN, and CNN, respectively. As for input modalities, 2D images of raw EEG waveforms yielded the best result with an AUC of 0.993. Thus, CNN can be the most suitable network structure for automated seizure detection when applied to the images of raw EEG waveforms, since CNN can effectively learn a general spatially-invariant representation of seizure patterns in 2D representations of raw EEG.
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Cho KO, Kim JY, Jeong KH, Lee MY, Kim SY. Increased expression of vascular endothelial growth factor-C and vascular endothelial growth factor receptor-3 after pilocarpine-induced status epilepticus in mice. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2019; 23:281-289. [PMID: 31297012 PMCID: PMC6609264 DOI: 10.4196/kjpp.2019.23.4.281] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 12/17/2022]
Abstract
Vascular endothelial growth factor (VEGF)-C and its receptor, vascular endothelial growth factor receptor (VEGFR)-3, are responsible for lymphangiogenesis in both embryos and adults. In epilepsy, the expression of VEGF-C and VEGFR-3 was significantly upregulated in the human brains affected with temporal lobe epilepsy. Moreover, pharmacologic inhibition of VEGF receptors after acute seizures could suppress the generation of spontaneous recurrent seizures, suggesting a critical role of VEGF-related signaling in epilepsy. Therefore, in the present study, the spatiotemporal expression of VEGF-C and VEGFR-3 against pilocarpine-induced status epilepticus (SE) was investigated in C57BL/6N mice using immunohistochemistry. At 1 day after SE, hippocampal astrocytes and microglia were activated. Pyramidal neuronal death was observed at 4 days after SE. In the subpyramidal zone, VEGF-C expression gradually increased and peaked at 7 days after SE, while VEGFR-3 was significantly upregulated at 4 days after SE and began to decrease at 7 days after SE. Most VEGF-C/VEGFR-3-expressing cells were pyramidal neurons, but VEGF-C was also observed in some astrocytes in sham-manipulated animals. However, at 4 days and 7 days after SE, both VEGFR-3 and VEGF-C immunoreactivities were observed mainly in astrocytes and in some microglia of the stratum radiatum and lacunosum-moleculare of the hippocampus, respectively. These data indicate that VEGF-C and VEGFR-3 can be upregulated in hippocampal astrocytes and microglia after pilocarpine-induced SE, providing basic information about VEGF-C and VEGFR-3 expression patterns following acute seizures.
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Affiliation(s)
- Kyung-Ok Cho
- Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.,Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seoul 06591, Korea.,Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.,Institute of Aging and Metabolic Diseases, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Joo Youn Kim
- Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Kyoung Hoon Jeong
- Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Mun-Yong Lee
- Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seoul 06591, Korea.,Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.,Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Seong Yun Kim
- Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.,Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seoul 06591, Korea.,Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
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Jang HJ, Kim JE, Jeong KH, Lim SC, Kim SY, Cho KO. The Neuroprotective Effect of Hericium erinaceus Extracts in Mouse Hippocampus after Pilocarpine-Induced Status Epilepticus. Int J Mol Sci 2019; 20:E859. [PMID: 30781501 PMCID: PMC6413080 DOI: 10.3390/ijms20040859] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/13/2019] [Accepted: 02/14/2019] [Indexed: 01/01/2023] Open
Abstract
Hericium erinaceus (HE), a culinary-medicinal mushroom, has shown therapeutic potential in many brain diseases. However, the role of HE in status epilepticus (SE)-mediated neuronal death and its underlying mechanisms remain unclear. We investigated the neuroprotective effects of HE using a pilocarpine-induced SE model. Male C57BL/6 mice received crude extracts of HE (60 mg/kg, 120 mg/kg, or 300 mg/kg, p.o.) for 21 d from 14 d before SE to 6 d after SE. At 7 d after SE, cresyl violet and immunohistochemistry of neuronal nuclei revealed improved hippocampal neuronal survival in animals treated with 60 mg/kg and 120 mg/kg of HE, whereas those treated with 300 mg/kg of HE showed similar neuronal death to that of vehicle-treated controls. While seizure-induced reactive gliosis, assessed by immunohistochemistry, was not altered by HE, the number of hippocampal cyclooxygenase 2 (COX2)-expressing cells was significantly reduced by 60 and 120 mg/kg of HE. Triple immunohistochemistry demonstrated no overlap of COX2 labeling with Ox42, in addition to a decrease in COX2/GFAP-co-immunoreactivity in the group treated with 60 mg/kg HE, suggesting that the reduction of COX2 by HE promotes neuroprotection after SE. Our findings highlight the potential application of HE for preventing neuronal death after seizures.
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Affiliation(s)
- Hyun-Jong Jang
- Department of Physiology, Department of Biomedicine and Health Sciences, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.
| | - Ji-Eun Kim
- Department of Pharmacology, Department of Biomedicine and Health Sciences, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.
| | - Kyoung Hoon Jeong
- Department of Pharmacology, Department of Biomedicine and Health Sciences, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.
- Department of Neurology and Epilepsy Research Institute, Yonsei University College of Medicine, Seoul 03722, Korea.
| | - Sung Chul Lim
- Department of Neurology, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.
| | - Seong Yun Kim
- Department of Pharmacology, Department of Biomedicine and Health Sciences, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.
| | - Kyung-Ok Cho
- Department of Pharmacology, Department of Biomedicine and Health Sciences, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.
- Institute of Aging and Metabolic Diseases, The Catholic University of Korea, Seoul 06591, Korea.
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Jang HJ, Cho KO. Dual deep neural network-based classifiers to detect experimental seizures. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2019; 23:131-139. [PMID: 30820157 PMCID: PMC6384195 DOI: 10.4196/kjpp.2019.23.2.131] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 01/09/2019] [Indexed: 12/23/2022]
Abstract
Manually reviewing electroencephalograms (EEGs) is labor-intensive and demands automated seizure detection systems. To construct an efficient and robust event detector for experimental seizures from continuous EEG monitoring, we combined spectral analysis and deep neural networks. A deep neural network was trained to discriminate periodograms of 5-sec EEG segments from annotated convulsive seizures and the pre- and post-EEG segments. To use the entire EEG for training, a second network was trained with non-seizure EEGs that were misclassified as seizures by the first network. By sequentially applying the dual deep neural networks and simple pre- and post-processing, our autodetector identified all seizure events in 4,272 h of test EEG traces, with only 6 false positive events, corresponding to 100% sensitivity and 98% positive predictive value. Moreover, with pre-processing to reduce the computational burden, scanning and classifying 8,977 h of training and test EEG datasets took only 2.28 h with a personal computer. These results demonstrate that combining a basic feature extractor with dual deep neural networks and rule-based pre- and post-processing can detect convulsive seizures with great accuracy and low computational burden, highlighting the feasibility of our automated seizure detection algorithm.
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Affiliation(s)
- Hyun-Jong Jang
- Department of Physiology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.,Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seoul 06591, Korea.,Catholic Neuroscience Institute, The Catholic University of Korea, Seoul 06591, Korea
| | - Kyung-Ok Cho
- Department of Biomedicine & Health Sciences, The Catholic University of Korea, Seoul 06591, Korea.,Catholic Neuroscience Institute, The Catholic University of Korea, Seoul 06591, Korea.,Institute of Aging and Metabolic Diseases, The Catholic University of Korea, Seoul 06591, Korea.,Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
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Hwang SN, Kim JC, Bhuiyan MIH, Kim JY, Yang JS, Yoon SH, Yoon KD, Kim SY. Black Rice ( Oryza sativa L., Poaceae) Extract Reduces Hippocampal Neuronal Cell Death Induced by Transient Global Cerebral Ischemia in Mice. Exp Neurobiol 2018; 27:129-138. [PMID: 29731679 PMCID: PMC5934544 DOI: 10.5607/en.2018.27.2.129] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/23/2018] [Accepted: 04/23/2018] [Indexed: 12/16/2022] Open
Abstract
Rice is the most commonly consumed grain in the world. Black rice has been suggested to contain various bioactive compounds including anthocyanin antioxidants. There is currently little information about the nutritional benefits of black rice on brain pathology. Here, we investigated the effects of black rice (Oryza sativa L., Poaceae) extract (BRE) on the hippocampal neuronal damage induced by ischemic insult. BRE (300 mg/kg) was orally administered to adult male C57BL/6 mice once a day for 21 days. Bilateral common carotid artery occlusion (BCCAO) was performed for 23 min on the 8th day of BRE or vehicle administration. Histological analyses conducted on the 22nd day of BRE or vehicle administration revealed that administering BRE profoundly attenuated neuronal cell death, inhibited reactive astrogliosis, and prevented loss of glutathione peroxidase expression in the hippocampus when compared to vehicle treatment. In addition, BRE considerably ameliorated BCCAO-induced memory impairment on the Morris water maze test from the 15th day to the 22nd day of BRE or vehicle administration. These results indicate that chronic administration of BRE is potentially beneficial in cerebral ischemia.
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Affiliation(s)
- Sun-Nyoung Hwang
- Department of Pharmacology, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Jae-Cheon Kim
- Department of Pharmacology, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Mohammad Iqbal Hossain Bhuiyan
- Department of Pharmacology, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Joo Youn Kim
- Department of Pharmacology, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Ji Seon Yang
- Department of Physiology, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Shin Hee Yoon
- Department of Physiology, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Kee Dong Yoon
- College of Pharmacy, The Catholic University of Korea, Bucheon 14662, Korea
| | - Seong Yun Kim
- Department of Pharmacology, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
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Yin KJ, Hamblin M, Fan Y, Zhang J, Chen YE. Krüpple-like factors in the central nervous system: novel mediators in stroke. Metab Brain Dis 2015; 30:401-10. [PMID: 24338065 PMCID: PMC4113556 DOI: 10.1007/s11011-013-9468-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 12/04/2013] [Indexed: 01/08/2023]
Abstract
Transcription factors play an important role in the pathophysiology of many neurological disorders, including stroke. In the past three decades, an increasing number of transcription factors and their related gene signaling networks have been identified, and have become a research focus in the stroke field. Krüppel-like factors (KLFs) are members of the zinc finger family of transcription factors with diverse regulatory functions in cell growth, differentiation, proliferation, migration, apoptosis, metabolism, and inflammation. KLFs are also abundantly expressed in the brain where they serve as critical regulators of neuronal development and regeneration to maintain normal brain function. Dysregulation of KLFs has been linked to various neurological disorders. Recently, there is emerging evidence that suggests KLFs have an important role in the pathogenesis of stroke and provide endogenous vaso-or neuro-protection in the brain's response to ischemic stimuli. In this review, we summarize the basic knowledge and advancement of these transcriptional mediators in the central nervous system, highlighting the novel roles of KLFs in stroke.
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Affiliation(s)
- Ke-Jie Yin
- Correspondence addressed to: Ke-Jie Yin, M.D., Ph.D., Cardiovascular Center, Department of Internal Medicine, University of Michigan Medical Center, Phone: 734-647-8975, Fax: 734-936-2641, , Y. Eugene Chen, M.D., Ph.D., Cardiovascular Center, Department of Internal Medicine, University of Michigan Medical Center, Phone: 734-763-7838, Fax: 734-936-2641,
| | | | | | | | - Y. Eugene Chen
- Correspondence addressed to: Ke-Jie Yin, M.D., Ph.D., Cardiovascular Center, Department of Internal Medicine, University of Michigan Medical Center, Phone: 734-647-8975, Fax: 734-936-2641, , Y. Eugene Chen, M.D., Ph.D., Cardiovascular Center, Department of Internal Medicine, University of Michigan Medical Center, Phone: 734-763-7838, Fax: 734-936-2641,
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Bhuiyan M, Kim JC, Hwang SN, Lee MY, Kim S. Ischemic tolerance is associated with VEGF-C and VEGFR-3 signaling in the mouse hippocampus. Neuroscience 2015; 290:90-102. [DOI: 10.1016/j.neuroscience.2015.01.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 01/14/2015] [Accepted: 01/16/2015] [Indexed: 10/24/2022]
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Induction of Krüppel-like factor 4 expression in reactive astrocytes following ischemic injury in vitro and in vivo. Histochem Cell Biol 2013; 141:33-42. [DOI: 10.1007/s00418-013-1134-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2013] [Indexed: 10/26/2022]
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Abstract
Reactive astrogliosis is characterized by a profound change in astrocyte phenotype in response to all CNS injuries and diseases. To better understand the reactive astrocyte state, we used Affymetrix GeneChip arrays to profile gene expression in populations of reactive astrocytes isolated at various time points after induction using two mouse injury models, ischemic stroke and neuroinflammation. We find reactive gliosis consists of a rapid, but quickly attenuated, induction of gene expression after insult and identify induced Lcn2 and Serpina3n as strong markers of reactive astrocytes. Strikingly, reactive astrocyte phenotype strongly depended on the type of inducing injury. Although there is a core set of genes that is upregulated in reactive astrocytes from both injury models, at least 50% of the altered gene expression is specific to a given injury type. Reactive astrocytes in ischemia exhibited a molecular phenotype that suggests that they may be beneficial or protective, whereas reactive astrocytes induced by LPS exhibited a phenotype that suggests that they may be detrimental. These findings demonstrate that, despite well established commonalities, astrocyte reactive gliosis is a highly heterogeneous state in which astrocyte activities are altered to respond to the specific injury. This raises the question of how many subtypes of reactive astrocytes exist. Our findings provide transcriptome databases for two subtypes of reactive astrocytes that will be highly useful in generating new and testable hypotheses of their function, as well as for providing new markers to detect different types of reactive astrocytes in human neurological diseases.
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Suppression of a MEF2-KLF6 survival pathway by PKA signaling promotes apoptosis in embryonic hippocampal neurons. J Neurosci 2012; 32:2790-803. [PMID: 22357862 DOI: 10.1523/jneurosci.3609-11.2012] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In the mammalian nervous system, regulation of transcription factor activity is a crucial determinant of neuronal cell survival, differentiation, and death. The myocyte enhancer factor 2 (MEF2) transcription factors have been implicated in cellular processes underlying neuronal survival and differentiation. A core component of the MEF2 complex is the MEF2D subunit. Recently, we reported that cAMP-dependent protein kinase (cAMP/PKA) signaling negatively regulates MEF2D function in myogenic cells. Here, we assessed whether cAMP signaling converges on the prosurvival role of MEF2D in Sprague Dawley rat embryonic (E18) hippocampal neurons. Initially, we observed that experimental induction of cAMP/PKA signaling promotes apoptosis in primary hippocampal neurons as indicated by TUNEL and FACS analysis. Luciferase reporter gene assays revealed that PKA potently represses MEF2D trans-activation properties in neurons. This effect was largely reversed by engineered neutralizing mutations of PKA phospho-acceptor sites on MEF2D (S121/190A). Krüppel-like factor 6 (KLF6) was identified as a key transcriptional target of MEF2 in hippocampal neurons, and siRNA-mediated knockdown of KLF6 expression promotes neuronal cell death and also antagonizes the prosurvival role of MEF2D. These observations have important implications for understanding the pathways controlling cell survival and death in the mammalian nervous system.
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