1
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Littleton SH, Trang KB, Volpe CM, Cook K, DeBruyne N, Maguire JA, Weidekamp MA, Hodge KM, Boehm K, Lu S, Chesi A, Bradfield JP, Pippin JA, Anderson SA, Wells AD, Pahl MC, Grant SFA. Variant-to-function analysis of the childhood obesity chr12q13 locus implicates rs7132908 as a causal variant within the 3' UTR of FAIM2. CELL GENOMICS 2024; 4:100556. [PMID: 38697123 PMCID: PMC11099382 DOI: 10.1016/j.xgen.2024.100556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 03/21/2024] [Accepted: 04/08/2024] [Indexed: 05/04/2024]
Abstract
The ch12q13 locus is among the most significant childhood obesity loci identified in genome-wide association studies. This locus resides in a non-coding region within FAIM2; thus, the underlying causal variant(s) presumably influence disease susceptibility via cis-regulation. We implicated rs7132908 as a putative causal variant by leveraging our in-house 3D genomic data and public domain datasets. Using a luciferase reporter assay, we observed allele-specific cis-regulatory activity of the immediate region harboring rs7132908. We generated isogenic human embryonic stem cell lines homozygous for either rs7132908 allele to assess changes in gene expression and chromatin accessibility throughout a differentiation to hypothalamic neurons, a key cell type known to regulate feeding behavior. The rs7132908 obesity risk allele influenced expression of FAIM2 and other genes and decreased the proportion of neurons produced by differentiation. We have functionally validated rs7132908 as a causal obesity variant that temporally regulates nearby effector genes and influences neurodevelopment and survival.
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Affiliation(s)
- Sheridan H Littleton
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Khanh B Trang
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Christina M Volpe
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kieona Cook
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Psychiatry, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nicole DeBruyne
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jean Ann Maguire
- Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Mary Ann Weidekamp
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Graduate Group in Genomics and Computational Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kenyaita M Hodge
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Keith Boehm
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Sumei Lu
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Alessandra Chesi
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jonathan P Bradfield
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Quantinuum Research LLC, San Diego, CA 92101, USA
| | - James A Pippin
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Stewart A Anderson
- Department of Child and Adolescent Psychiatry, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andrew D Wells
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Matthew C Pahl
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Struan F A Grant
- Center for Spatial and Functional Genomics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Endocrinology and Diabetes, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
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2
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Littleton SH, Trang KB, Volpe CM, Cook K, DeBruyne N, Ann Maguire J, Ann Weidekamp M, Boehm K, Chesi A, Pippin JA, Anderson SA, Wells AD, Pahl MC, Grant SF. Variant-to-function analysis of the childhood obesity chr12q13 locus implicates rs7132908 as a causal variant within the 3' UTR of FAIM2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.21.553157. [PMID: 37662342 PMCID: PMC10473629 DOI: 10.1101/2023.08.21.553157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
The ch12q13 obesity locus is among the most significant childhood obesity loci identified in genome-wide association studies. This locus resides in a non-coding region within FAIM2; thus, the underlying causal variant(s) presumably influence disease susceptibility via an influence on cis-regulation within the genomic region. We implicated rs7132908 as a putative causal variant at this locus leveraging a combination of our inhouse 3D genomic data, public domain datasets, and several computational approaches. Using a luciferase reporter assay in human primary astrocytes, we observed allele-specific cis-regulatory activity of the immediate region harboring rs7132908. Motivated by this finding, we went on to generate isogenic human embryonic stem cell lines homozygous for either rs7132908 allele with CRISPR-Cas9 homology-directed repair to assess changes in gene expression due to genotype and chromatin accessibility throughout a differentiation to hypothalamic neurons, a key cell type known to regulate feeding behavior. We observed that the rs7132908 obesity risk allele influenced the expression of FAIM2 along with other genes, decreased the proportion of neurons produced during differentiation, up-regulated cell death gene sets, and conversely down-regulated neuron differentiation gene sets. We have therefore functionally validated rs7132908 as a causal obesity variant which temporally regulates nearby effector genes at the ch12q13 locus and influences neurodevelopment and survival.
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Affiliation(s)
- Sheridan H. Littleton
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Khanh B. Trang
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Christina M. Volpe
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kieona Cook
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Psychiatry, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Nicole DeBruyne
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jean Ann Maguire
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Mary Ann Weidekamp
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Graduate Group in Genomics and Computational Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Keith Boehm
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Alessandra Chesi
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James A. Pippin
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Stewart A. Anderson
- Department of Child and Adolescent Psychiatry, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andrew D. Wells
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Institute for Immunology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Matthew C. Pahl
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Struan F.A. Grant
- Center for Spatial and Functional Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Division of Human Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Division of Endocrinology and Diabetes, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
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Arik E, Heinisch O, Bienert M, Gubeljak L, Slowik A, Reich A, Schulz JB, Wilhelm T, Huber M, Habib P. Erythropoietin Enhances Post-ischemic Migration and Phagocytosis and Alleviates the Activation of Inflammasomes in Human Microglial Cells. Front Cell Neurosci 2022; 16:915348. [PMID: 35813499 PMCID: PMC9263298 DOI: 10.3389/fncel.2022.915348] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 06/08/2022] [Indexed: 11/19/2022] Open
Abstract
Recombinant human erythropoietin (rhEPO) has been shown to exert anti-apoptotic and anti-inflammatory effects after cerebral ischemia. Inflammatory cytokines interleukin-1β and -18 (IL-1β and IL-18) are crucial mediators of apoptosis and are maturated by multiprotein complexes termed inflammasomes. Microglia are the first responders to post-ischemic brain damage and are a main source of inflammasomes. However, the impact of rhEPO on microglial activation and the subsequent induction of inflammasomes after ischemia remains elusive. To address this, we subjected human microglial clone 3 (HMC-3) cells to various durations of oxygen-glucose-deprivation/reperfusion (OGD/R) to assess the impact of rhEPO on cell viability, metabolic activity, oxidative stress, phagocytosis, migration, as well as on the regulation and activation of the NLRP1, NLRP3, NLRC4, and AIM2 inflammasomes. Administration of rhEPO mitigated OGD/R-induced oxidative stress and cell death. Additionally, it enhanced metabolic activity, migration and phagocytosis of HMC-3. Moreover, rhEPO attenuated post-ischemic activation and regulation of the NLRP1, NLRP3, NLRC4, and AIM2 inflammasomes as well as their downstream effectors CASPASE1 and IL-1β. Pharmacological inhibition of NLRP3 via MCC950 had no effect on the activation of CASPASE1 and maturation of IL-1β after OGD/R, but increased protein levels of NLRP1, NLRC4, and AIM2, suggesting compensatory activities among inflammasomes. We provide evidence that EPO-conveyed anti-inflammatory actions might be mediated via the regulation of the inflammasomes.
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Affiliation(s)
- Eren Arik
- Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Ole Heinisch
- Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Michaela Bienert
- Institute of Molecular and Cellular Anatomy, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Lara Gubeljak
- Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Alexander Slowik
- Department of Anatomy and Cell Biology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Arno Reich
- Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Jörg B. Schulz
- Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany
- JARA-BRAIN Institute of Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Thomas Wilhelm
- Institute of Biochemistry and Molecular Immunology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Michael Huber
- Institute of Biochemistry and Molecular Immunology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Pardes Habib
- Department of Neurology, Medical Faculty, RWTH Aachen University, Aachen, Germany
- JARA-BRAIN Institute of Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
- *Correspondence: Pardes Habib, ; orcid.org/0000-0002-5771-216X
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Ma Y, Zhou Z, Yang GY, Ding J, Wang X. The Effect of Erythropoietin and Its Derivatives on Ischemic Stroke Therapy: A Comprehensive Review. Front Pharmacol 2022; 13:743926. [PMID: 35250554 PMCID: PMC8892214 DOI: 10.3389/fphar.2022.743926] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 01/19/2022] [Indexed: 12/17/2022] Open
Abstract
Numerous studies explored the therapeutic effects of erythropoietin (EPO) on neurodegenerative diseases. Few studies provided comprehensive and latest knowledge of EPO treatment for ischemic stroke. In the present review, we introduced the structure, expression, function of EPO, and its receptors in the central nervous system. Furthermore, we comprehensively discussed EPO treatment in pre-clinical studies, clinical trials, and its therapeutic mechanisms including suppressing inflammation. Finally, advanced studies of the therapy of EPO derivatives in ischemic stroke were also discussed. We wish to provide valuable information on EPO and EPO derivatives’ treatment for ischemic stroke for basic researchers and clinicians to accelerate the process of their clinical applications.
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Affiliation(s)
- Yuanyuan Ma
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zhiyuan Zhou
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Guo-Yuan Yang
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- *Correspondence: Guo-Yuan Yang, ; Jing Ding,
| | - Jing Ding
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
- *Correspondence: Guo-Yuan Yang, ; Jing Ding,
| | - Xin Wang
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
- Department of The State Key Laboratory of Medical Neurobiology, The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
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Erythropoietin Abrogates Post-Ischemic Activation of the NLRP3, NLRC4, and AIM2 Inflammasomes in Microglia/Macrophages in a TAK1-Dependent Manner. Transl Stroke Res 2021; 13:462-482. [PMID: 34628598 PMCID: PMC9046144 DOI: 10.1007/s12975-021-00948-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 08/18/2021] [Accepted: 09/18/2021] [Indexed: 12/18/2022]
Abstract
Inflammasomes are known to contribute to brain damage after acute ischemic stroke (AIS). TAK1 is predominantly expressed in microglial cells and can regulate the NLRP3 inflammasome, but its impact on other inflammasomes including NLRC4 and AIM2 after AIS remains elusive. EPO has been shown to reduce NLRP3 protein levels in different disease models. Whether EPO-mediated neuroprotection after AIS is conveyed via an EPO/TAK1/inflammasome axis in microglia remains to be clarified. Subjecting mice deficient for TAK1 in microglia/macrophages (Mi/MΦ) to AIS revealed a significant reduction in infarct sizes and neurological impairments compared to the corresponding controls. Post-ischemic increased activation of TAK1, NLRP3, NLRC4, and AIM2 inflammasomes including their associated downstream cascades were markedly reduced upon deletion of Mi/MΦ TAK1. EPO administration improved clinical outcomes and dampened stroke-induced activation of TAK1 and inflammasome cascades, which was not evident after the deletion of Mi/MΦ TAK1. Pharmacological inhibition of NLRP3 in microglial BV-2 cells did not influence post-OGD IL-1β levels, but increased NLRC4 and AIM2 protein levels, suggesting compensatory activities among inflammasomes. Overall, we provide evidence that Mi/MΦ TAK1 regulates the expression and activation of the NLRP3, NLRC4, AIM2 inflammasomes. Furthermore, EPO mitigated stroke-induced activation of TAK1 and inflammasomes, indicating that EPO conveyed neuroprotection might be mediated via an EPO/TAK1/inflammasome axis.
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Chen X, Sun W, Zhong P, Wu D. Colony-Stimulating Factors on Mobilizing CD34 + Cells and Improving Neurological Functions in Patients With Stroke: A Meta-Analysis and a Systematic Review. Front Pharmacol 2021; 12:704509. [PMID: 34366857 PMCID: PMC8339259 DOI: 10.3389/fphar.2021.704509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 06/07/2021] [Indexed: 11/13/2022] Open
Abstract
Background and Purpose: CSF therapy is considered a promising therapeutic approach for stroke. We performed a meta-analysis to explore the safety and efficacy of CSF in published clinical stroke studies. Methods: We searched articles online and manually. Two reviewers selected studies independently, selecting data based on study quality, characteristics of intervention (administration time, observation time, type, dose, and injection approach of CSF), and the baseline characteristics of patients (age, sex, hypertension, diabetes, smoker, and lipids) were extracted. Main prognosis outcomes were measured as all-cause death in severe adverse events (SAE) and recurrent stroke in SAE. Secondary outcomes were measured as CD34+ cell counts in periphery blood at day 5, National Institutes of Health Stroke Scale (NIHSS), and Barthel index (BI), Side effects of CSF were taken as the indicator of safety. STATA13 software was used to perform the meta-analysis.Keywords: Stroke, Colony-stimulating factor, Meta-analysis, therapy, Neurological Diseases Results: This meta-analysis involved 485 patients from eight studies. Among them, 475 patients from seven studies were gauged SAE (all-cause death), 393 patients from six studies were checked SAE (recurrent stroke); 137 patients from three studies underwent CD34+ measurement, 389 patients from six studies were tested NIHSS and 307 patients from five studies accessed BI. Compared with the control group, both all-causes death (RR= 1.73, 95%CI= (0.61, 4.92), P=0.735, I2=0.0%) and recurrent stroke (RR= 0.43, 95%CI= (0.14, 1.32), P=0.214, I2=33.1%) present no statistical differences, indicating that the application of CSF does not statistically alter the prognosis of patients with stroke. The application of CSF effectively enhanced CD34+ cell counts in periphery blood at day 5 (SMD= 1.23, 95%CI= (0.54, 1.92), P=0.04, I2=69.0%) but did not statistically impact NIHSS (SMD= -0.40, 95%CI= (-0.93, 0.13), P ≤ 0.001, I2=79.7%) or BI (SMD= 0.04, 95%CI= (-0.38, 0.46), P=0.068, I2=54.3%). Conclusion: Our study consolidates the security of CSF administration for its exerting no effect on detrimental outcomes. It has proven to be effective in elevating CD34+ cell counts in periphery blood at day 5, indicating CSF may participate in stroke recovery, but its efficacy in stroke recovery remains detected.
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Affiliation(s)
- Xiuqi Chen
- Department of Neurology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Wenbo Sun
- Department of Neurology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
| | - Ping Zhong
- Department of Neurology, Shidong Hospital Affiliated to University of Shanghai for Science and Technology, Shanghai, China
| | - Danhong Wu
- Department of Neurology, Shanghai Fifth People's Hospital, Fudan University, Shanghai, China
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The Role of PI3K/AKT and MAPK Signaling Pathways in Erythropoietin Signalization. Int J Mol Sci 2021; 22:ijms22147682. [PMID: 34299300 PMCID: PMC8307237 DOI: 10.3390/ijms22147682] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 12/11/2022] Open
Abstract
Erythropoietin (EPO) is a glycoprotein cytokine known for its pleiotropic effects on various types of cells and tissues. EPO and its receptor EPOR trigger signaling cascades JAK2/STAT5, MAPK, and PI3K/AKT that are interconnected and irreplaceable for cell survival. In this article, we describe the role of the MAPK and PI3K/AKT signaling pathways during red blood cell formation as well as in non-hematopoietic tissues and tumor cells. Although the central framework of these pathways is similar for most of cell types, there are some stage-specific, tissue, and cell-lineage differences. We summarize the current state of research in this field, highlight the novel members of EPO-induced PI3K and MAPK signaling, and in this respect also the differences between erythroid and non-erythroid cells.
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Chen K, Yang LN, Lai C, Liu D, Zhu LQ. Role of Grina/Nmdara1 in the Central Nervous System Diseases. Curr Neuropharmacol 2021; 18:861-867. [PMID: 32124700 PMCID: PMC7569322 DOI: 10.2174/1570159x18666200303104235] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 01/11/2020] [Accepted: 02/13/2020] [Indexed: 12/24/2022] Open
Abstract
Glutamate receptor, ionotropic, N-methyl-D-aspartate associated protein 1 (GRINA) is a member of the NMDA receptors (NMDARs) and is involved in several neurological diseases, which governs the key processes of neuronal cell death or the release of neurotransmitters. Upregulation of GRINA has been reported in multiple diseases in human beings, such as major depressive disorder (MDD) and schizophrenia (SCZ), with which the underlying mechanisms remain elusive. In this review, we provide a general overview of the expression and physiological function of GRINA in the central nervous system (CNS) diseases, including stroke, depression, epilepsy, SCZ, and Alzheimer’s disease (AD).
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Affiliation(s)
- Kai Chen
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine,
Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People’s Republic of China,The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, People’s Republic of China
| | - Liu Nan Yang
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine,
Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People’s Republic of China,The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, People’s Republic of China
| | - Chuan Lai
- Department of Medical Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science
and Technology, Wuhan 430030, People’s Republic of China,The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, People’s Republic of China
| | - Dan Liu
- Department of Medical Genetics, School of Basic Medicine, Tongji Medical College, Huazhong University of Science
and Technology, Wuhan 430030, People’s Republic of China,The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, People’s Republic of China
| | - Ling-Qiang Zhu
- Department of Pathophysiology, Key Lab of Neurological Disorder of Education Ministry, School of Basic Medicine,
Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, People’s Republic of China,The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, People’s Republic of China
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Abstract
This review summarizes the available data about genetic factors which can link ischemic stroke and sleep. Sleep patterns (subjective and objective measures) are characterized by heritability and comprise up to 38-46%. According to Mendelian randomization analysis, genetic liability for short sleep duration and frequent insomnia symptoms is associated with ischemic stroke (predominantly of large artery subtype). The potential genetic links include variants of circadian genes, genes encoding components of neurotransmitter systems, common cardiovascular risk factors, as well as specific genetic factors related to certain sleep disorders.
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Affiliation(s)
- Lyudmila Korostovtseva
- Sleep Laboratory, Research Department for Hypertension, Department for Cardiology, Almazov National Medical Research Centre, 2 Akkuratov Str., Saint Petersburg, 197341, Russia.
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10
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Cytoprotective effects of erythropoietin: What about the lung? Biomed Pharmacother 2021; 139:111547. [PMID: 33831836 DOI: 10.1016/j.biopha.2021.111547] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/17/2021] [Accepted: 03/23/2021] [Indexed: 02/07/2023] Open
Abstract
Erythropoietin (Epo) is a pleiotropic cytokine, essential for erythropoiesis. Epo and its receptor (Epo-R) are produced by several tissues and it is now admitted that Epo displays other physiological functions than red blood cell synthesis. Indeed, Epo provides cytoprotective effects, which consist in prevention or fight against pathological processes. This perspective article reviews the various protective effects of Epo in several organs and tries to give a proof of concept about its effects in the lung. The tissue-protective effects of Epo could be a promising approach to limit the symptoms of acute and chronic lung diseases.
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11
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Thompson A, Farmer K, Rowe E, Hayley S. Erythropoietin modulates striatal antioxidant signalling to reduce neurodegeneration in a toxicant model of Parkinson's disease. Mol Cell Neurosci 2020; 109:103554. [DOI: 10.1016/j.mcn.2020.103554] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 09/02/2020] [Accepted: 09/04/2020] [Indexed: 12/13/2022] Open
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12
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Lee TH, Yang JT, Lin JR, Hu CJ, Chou WH, Lin CP, Chi NF. Protective effects of ischemic preconditioning against neuronal apoptosis and dendritic injury in the hippocampus are age-dependent. J Neurochem 2020; 155:430-447. [PMID: 32314365 DOI: 10.1111/jnc.15029] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 12/13/2022]
Abstract
Ischemic preconditioning with non-lethal ischemia can be protective against lethal forebrain ischemia. We hypothesized that aging may aggravate ischemic susceptibility and reduce brain plasticity against preconditioning. Magnetic resonance diffusion tensor imaging (DTI) is a sensitive tool to detect brain integrity and white matter architecture. This study used DTI and histopathology to investigate the effect of aging on ischemic preconditioning. In this study, adult and middle-aged male Mongolian gerbils were subjected to non-lethal 5-min forebrain ischemia (ischemic preconditioning) or sham-operation, followed by 3 days of reperfusion, and then lethal 15-min forebrain ischemia. A 9.4-Tesla MR imaging system was used to study DTI indices, namely fractional anisotropy (FA), mean diffusivity (MD), and intervoxel coherence (IC) in the hippocampal CA1 and dentate gyrus (DG) areas. In situ expressions of microtubule-associated protein 2 (MAP2, dendritic marker protein) and apoptosis were also examined. The 5-min ischemia did not cause dendritic and neuronal injury and any significant change in DTI indices and MAP2 in adult and middle-aged gerbils. The 15-min ischemia-induced significant delayed neuronal apoptosis and early dendritic injury evidenced by DTI and MAP2 studies in both CA1 and DG areas with more severe injury in middle-aged gerbils than adult gerbils. Ischemic preconditioning could improve neuronal apoptosis in CA1 area and dendritic integrity in both CA1 and DG areas with better improvement in adult gerbils than middle-aged gerbils. This study thus suggests an age-dependent protective effect of ischemic preconditioning against both neuronal apoptosis and dendritic injury in hippocampus after forebrain ischemia.
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Affiliation(s)
- Tsong-Hai Lee
- Stroke Center and Department of Neurology, Chang Gung Memorial Hospital, Linkou Medical Center, and College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Jen-Tsung Yang
- Department of Neurosurgery, Chiayi Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Jr-Rung Lin
- Clinical Informatics and Medical Statistics Research Center, Chang Gung University, Taoyuan, Taiwan
| | - Chaur-Jong Hu
- Department of Neurology, Shuang-Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Wen-Hai Chou
- Center for Neuropsychiatric Research, National Health Research Institutes, Miaoli, Taiwan
| | - Ching-Po Lin
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan
| | - Nai-Fang Chi
- Department of Neurology, Faculty of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan
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13
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Toriuchi K, Kakita H, Tamura T, Takeshita S, Yamada Y, Aoyama M. Prolonged astrocyte-derived erythropoietin expression attenuates neuronal damage under hypothermic conditions. J Neuroinflammation 2020; 17:141. [PMID: 32359362 PMCID: PMC7195727 DOI: 10.1186/s12974-020-01831-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 04/27/2020] [Indexed: 02/07/2023] Open
Abstract
Background Hypoxic-ischemic encephalopathy (HIE) has a high morbidity rate and involves severe neurologic deficits, including cerebral palsy. Therapeutic hypothermia (TH) has been shown to decrease the mortality rate and provide neuroprotection in infants with HIE. However, death and disability rates in HIE infants treated with TH remain high. Although the cellular mechanism of the neuroprotective effect of TH remains unclear, astrocytic erythropoietin (EPO) is known to be a key mediator of neuroprotection under hypoxic conditions. In the present study, we investigated the hypothermia effect on EPO expression in astrocytes and determined whether hypothermia attenuates neuronal damage via EPO signaling. Methods Astrocytes derived from rat cerebral cortex were cultured under oxygen/glucose deprivation (OGD). The expression of EPO and hypoxia-inducible factor (HIF), a transcription factor of EPO, was assessed. After OGD, astrocytes were cultured under normothermic (37 °C) or hypothermic (33.5 °C) conditions, and then EPO and HIF expression was assessed. After OGD, rat cortical neurons were cultured in astrocyte-conditioned medium (ACM) derived from the hypothermic group, and neuronal apoptosis was evaluated. Results OGD induced EPO mRNA and protein expression, although at lower levels than hypoxia alone. HIF-1α and HIF-2α protein expression increased under hypoxia alone and OGD, although OGD increased HIF-2α protein expression less than hypoxia alone. EPO gene and protein expression after OGD was significantly higher under hypothermia. Moreover, expression of HIF-1α and HIF-2α protein was enhanced under hypothermia. In the presence of ACM derived from hypothermic astrocytes following OGD, the number of cleaved caspase 3 and TdT-mediated dUTP nick-end labeling-positive apoptotic neurons was lower than in the presence of ACM from normothermic astrocytes following OGD. Blockade of EPO signaling using anti-EPO neutralization antibody attenuated the anti-apoptotic effect of ACM derived from hypothermic astrocytes following OGD. Conclusions Hypothermia after OGD stabilized HIF-EPO signaling in astrocytes, and upregulated EPO expression could suppress neuronal apoptosis. Investigating the neuroprotective effect of EPO from astrocytes under hypothermic conditions may contribute to the development of novel neuroprotection-based therapies for HIE.
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Affiliation(s)
- Kohki Toriuchi
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, 3-1 Tanabedori, Mizoho-ku, Nagoya, Aichi, 467-8603, Japan
| | - Hiroki Kakita
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, 3-1 Tanabedori, Mizoho-ku, Nagoya, Aichi, 467-8603, Japan.,Department of Perinatal and Neonatal Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan
| | - Tetsuya Tamura
- Department of Anesthesiology and Intensive Care Medicine, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-ku, Nagoya, Aichi, 467-8601, Japan
| | - Satoru Takeshita
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, 3-1 Tanabedori, Mizoho-ku, Nagoya, Aichi, 467-8603, Japan.,Department of Perinatal and Neonatal Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan
| | - Yasumasa Yamada
- Department of Perinatal and Neonatal Medicine, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi, 480-1195, Japan
| | - Mineyoshi Aoyama
- Department of Pathobiology, Nagoya City University Graduate School of Pharmaceutical Sciences, 3-1 Tanabedori, Mizoho-ku, Nagoya, Aichi, 467-8603, Japan.
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14
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Habib P, Stamm AS, Schulz JB, Reich A, Slowik A, Capellmann S, Huber M, Wilhelm T. EPO and TMBIM3/GRINA Promote the Activation of the Adaptive Arm and Counteract the Terminal Arm of the Unfolded Protein Response after Murine Transient Cerebral Ischemia. Int J Mol Sci 2019; 20:ijms20215421. [PMID: 31683519 PMCID: PMC6862264 DOI: 10.3390/ijms20215421] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/24/2019] [Accepted: 10/30/2019] [Indexed: 12/16/2022] Open
Abstract
Ischemic stroke is known to cause the accumulation of misfolded proteins and loss of calcium homeostasis leading to impairment of endoplasmic reticulum (ER) function. The unfolded protein response (UPR) is an ER-located and cytoprotective pathway that aims to resolve ER stress. Transmembrane BAX inhibitor-1 motif-containing (TMBIM) protein family member TMBIM3/GRINA is highly expressed in the brain and mostly located at the ER membrane suppressing ER calcium release by inositol-1,4,5-trisphosphate receptors. GRINA confers neuroprotection and is regulated by erythropoietin (EPO) after murine cerebral ischemia. However, the role of GRINA and the impact of EPO treatment on the post-ischemic UPR have not been elucidated yet. We subjected GRINA-deficient (Grina−/−) and wildtype mice to transient (30 min) middle cerebral artery occlusion (tMCAo) followed by 6 h or 72 h of reperfusion. We administered EPO or saline 0, 24 and 48 h after tMCAo/sham surgery. Oxygen–glucose deprivation (OGD) and pharmacological stimulation of the UPR using Tunicamycin and Thapsigargin were carried out in primary murine cortical mixed cell cultures. Treatment with the PERK-inhibitor GSK-2606414, IRE1a-RNase-inhibitor STF-083010 and EPO was performed 1 h prior to either 1 h, 2 h or 3 h of OGD. We found earlier and larger infarct demarcations in Grina−/− mice compared to wildtype mice, which was accompanied by a worse neurological outcome and an abolishment of EPO-mediated neuroprotection after ischemic stroke. In addition, GRINA-deficiency increased apoptosis and the activation of the corresponding PERK arm of the UPR after stroke. EPO enhanced the post-ischemic activation of pro-survival IRE1a and counteracted the pro-apoptotic PERK branch of the UPR. Both EPO and the PERK-inhibitor GSK-2606414 reduced cell death and regulated Grina mRNA levels after OGD. In conclusion, GRINA plays a crucial role in post-ischemic UPR and the use of both GSK-2606414 and EPO might lead to neuroprotection.
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MESH Headings
- Adenine/analogs & derivatives
- Adenine/pharmacology
- Animals
- Apoptosis/drug effects
- Apoptosis/genetics
- Cells, Cultured
- Endoplasmic Reticulum Stress/drug effects
- Endoplasmic Reticulum Stress/genetics
- Erythropoietin/pharmacology
- Glucose/metabolism
- Indoles/pharmacology
- Infarction, Middle Cerebral Artery/genetics
- Infarction, Middle Cerebral Artery/metabolism
- Infarction, Middle Cerebral Artery/prevention & control
- Ischemic Attack, Transient/genetics
- Ischemic Attack, Transient/metabolism
- Ischemic Attack, Transient/prevention & control
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice, 129 Strain
- Mice, Inbred C57BL
- Mice, Knockout
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Neuroprotective Agents/pharmacology
- Oxygen/metabolism
- Sulfonamides/pharmacology
- Thapsigargin/pharmacology
- Thiophenes/pharmacology
- Tunicamycin/pharmacology
- Unfolded Protein Response/drug effects
- Unfolded Protein Response/genetics
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Affiliation(s)
- Pardes Habib
- Department of Neurology, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany.
| | - Ann-Sophie Stamm
- Department of Neurology, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany.
| | - Joerg B Schulz
- Department of Neurology, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany.
- JARA-BRAIN Institute Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbAnd RWTH Aachen University, 52074 Aachen, Germany.
| | - Arno Reich
- Department of Neurology, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany.
| | - Alexander Slowik
- Institute of Neuroanatomy, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany.
| | - Sandro Capellmann
- Institute of Biochemistry and Molecular Immunology, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany.
| | - Michael Huber
- Institute of Biochemistry and Molecular Immunology, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany.
| | - Thomas Wilhelm
- Institute of Biochemistry and Molecular Immunology, Medical Faculty, RWTH Aachen University, 52074 Aachen, Germany.
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15
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Habib P, Stamm AS, Zeyen T, Noristani R, Slowik A, Beyer C, Wilhelm T, Huber M, Komnig D, Schulz JB, Reich A. EPO regulates neuroprotective Transmembrane BAX Inhibitor-1 Motif-containing (TMBIM) family members GRINA and FAIM2 after cerebral ischemia-reperfusion injury. Exp Neurol 2019; 320:112978. [PMID: 31211943 DOI: 10.1016/j.expneurol.2019.112978] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/03/2019] [Accepted: 06/12/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND PURPOSE Transmembrane BAX Inhibitor-1 Motif-containing (TMBIM) family members exert inhibitory activities in apoptosis and necroptosis. FAIM2 (TMBIM-2) is neuroprotective against murine focal ischemia and is regulated by erythropoietin (EPO). Similar to FAIM2, GRINA (TMBIM-3) is predominantly expressed in the brain. The role of GRINA in transient brain ischemia, its potential synergistic effects with FAIM2 and its regulation by EPO treatment were assessed. METHODS We performed transient (30 min) middle cerebral artery occlusion (tMCAo) followed by 72 h of reperfusion in GRINA-deficient (GRINA-/-), FAIM2-deficient (FAIM2-/-), double-deficient (GRINA-/-FAIM2-/-) and wildtype littermates (WT) mice. We administered EPO or saline 0, 24 and 48 h after tMCAo. We subjected primary murine cortical neurons (pMCN) of all mouse strains to oxygen-glucose deprivation (OGD) after GRINA and/or FAIM2 gene transfection. RESULTS Compared to wildtype controls GRINA deficiency led to a similar increase in infarct volumes as FAIM2 deficiency (p < .01). We observed the highest neurological deficits and largest infarct sizes in double-deficient mice. EPO administration upregulated GRINA and FAIM2 mRNA levels in wildtype littermates. EPO decreased infarct sizes and abrogated neurological impairments in wildtype controls. GRINA and/or FAIM2 deficient mice showed increased expression levels of cleaved-caspase 3 and of pro-apoptotic BAX mRNA. Further, caspase 8 was upregulated in FAIM2-/- and caspase 9 in GRINA-/- mice. Overexpression of GRINA and FAIM2 in wildtype and in double deficient pMCN decreased cell death rate after OGD. CONCLUSIONS GRINA and FAIM2 are highly expressed in the brain and convey EPO-mediated neuroprotection after ischemic stroke involving different caspases.
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Affiliation(s)
- Pardes Habib
- Department of Neurology, Medical School, RWTH Aachen University, Aachen, Germany.
| | - Ann-Sophie Stamm
- Department of Neurology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Thomas Zeyen
- Department of Neurology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Rozina Noristani
- Department of Neurology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Alexander Slowik
- Institute of Neuroanatomy, Medical School, RWTH Aachen University, Aachen, Germany
| | - Cordian Beyer
- Institute of Neuroanatomy, Medical School, RWTH Aachen University, Aachen, Germany
| | - Thomas Wilhelm
- Institute of Biochemistry and Molecular Immunology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Michael Huber
- Institute of Biochemistry and Molecular Immunology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Daniel Komnig
- Department of Neurology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Jörg B Schulz
- Department of Neurology, Medical School, RWTH Aachen University, Aachen, Germany; JARA-BRAIN Institute of Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbH and RWTH Aachen University, Aachen, Germany
| | - Arno Reich
- Department of Neurology, Medical School, RWTH Aachen University, Aachen, Germany
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16
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Lee BJ, Jun HO, Kim JH, Kim JH. Astrocytic cystine/glutamate antiporter is a key regulator of erythropoietin expression in the ischemic retina. FASEB J 2019; 33:6045-6054. [PMID: 30742774 DOI: 10.1096/fj.201802144r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Ischemic retinopathies and optic neuropathies are important causes of vision loss. The neuroprotective effect of erythropoietin (EPO) in ischemic neuronal injury and the expression of EPO and its receptor in retinal tissue have been well documented. However, the exact regulatory mechanism of EPO expression in retinal ischemia still remains to be elucidated. In this study, we investigated the role of cystine/glutamate antiporter (system xc-) in the regulation of astrocytic EPO expression by using both in vitro and in vivo models. Under hypoxia, the expression of astrocytic system xc- is up-regulated both in vitro and in vivo. Inhibition of system xc- resulted in depletion of intracellular glutathione (GSH) and decrement of GSH disulfide ratios in human brain astrocytes (HBAs). In HBAs, hypoxia-induced stabilization of hypoxia-inducible factor (Hif)-2α is nearly completely abolished by inhibition of system xc-. Hypoxia-induced up-regulation of astrocytic EPO expression is suppressed by both pharmacological inhibition and siRNA-mediated knockdown of system xc-. In contrast, basal EPO expression under normoxia is not affected by system xc- modulation. In summary, under hypoxia, increased system xc- acts as the major source of intracellular GSH, which helps in stabilizing Hif-2α and subsequent up-regulation of EPO in astrocytes.-Lee, B. J., Jun, H. O., Kim, J. H., Kim, J. H. Astrocytic cystine/glutamate antiporter is a key regulator of erythropoietin expression in the ischemic retina.
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Affiliation(s)
- Byung Joo Lee
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul National University, Seoul, South Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul National University, Seoul, South Korea
| | - Hyoung Oh Jun
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul National University, Seoul, South Korea
| | - Jin Hyoung Kim
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul National University, Seoul, South Korea
| | - Jeong Hun Kim
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Clinical Research Institute, Seoul National University Hospital, Seoul National University, Seoul, South Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul National University, Seoul, South Korea.,Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University, Seoul, South Korea
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