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Wilson KM, He JJ. HIV Nef Expression Down-modulated GFAP Expression and Altered Glutamate Uptake and Release and Proliferation in Astrocytes. Aging Dis 2023; 14:152-169. [PMID: 36818564 PMCID: PMC9937695 DOI: 10.14336/ad.2022.0712] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 07/12/2022] [Indexed: 11/18/2022] Open
Abstract
HIV infection of astrocytes leads to restricted gene expression and replication but abundant expression of HIV early genes Tat, Nef and Rev. A great deal of neuroHIV research has so far been focused on Tat protein, its effects on astrocytes, and its roles in neuroHIV. In the current study, we aimed to determine effects of Nef expression on astrocytes and their function. Using transfection or infection of VSVG-pseudotyped HIV viruses, we showed that Nef expression down-modulated glial fibrillary acidic protein (GFAP) expression. We then showed that Nef expression also led to decreased GFAP mRNA expression. The transcriptional regulation was further confirmed using a GFAP promoter-driven reporter gene assay. We performed transcription factor profiling array to compare the expression of transcription factors between Nef-intact and Nef-deficient HIV-infected cells and identified eight transcription factors with expression changes of 1.5-fold or higher: three up-regulated by Nef (Stat1, Stat5, and TFIID), and five down-regulated by Nef (AR, GAS/ISRE, HIF, Sp1, and p53). We then demonstrated that removal of the Sp1 binding sites from the GFAP promoter resulted in a much lower level of the promoter activity and reversal of Nef effects on the GFAP promoter, confirming important roles of Sp1 in the GFAP promoter activity and for Nef-induced GFAP expression. Lastly, we showed that Nef expression led to increased glutamate uptake and decreased glutamate release by astrocytes and increased astrocyte proliferation. Taken together, these results indicate that Nef leads to down-modulation of GFAP expression and alteration of glutamate metabolism in astrocytes, and astrocyte proliferation and could be an important contributor to neuroHIV.
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Affiliation(s)
- Kelly M Wilson
- Department of Microbiology and Immunology, Center for Cancer Cell Biology, Immunology and Infection, School of Graduate and Postdoctoral Studies, Rosalind Franklin University, Chicago Medical School, North Chicago, IL 60064, USA
| | - Johnny J He
- Department of Microbiology and Immunology, Center for Cancer Cell Biology, Immunology and Infection, School of Graduate and Postdoctoral Studies, Rosalind Franklin University, Chicago Medical School, North Chicago, IL 60064, USA
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2
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Samtleben S, Mina L, Yap MC, Branton WG, Yousuf MS, Tenorio G, Ballanyi K, Giuliani F, Kerr BJ, Power C, Simmen T. Astrocytes show increased levels of Ero1α in multiple sclerosis and its experimental autoimmune encephalomyelitis animal model. Eur J Neurosci 2022; 56:5177-5190. [PMID: 36083288 DOI: 10.1111/ejn.15817] [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: 07/19/2021] [Revised: 06/23/2022] [Accepted: 07/15/2022] [Indexed: 12/14/2022]
Abstract
Multiple sclerosis (MS) and its animal models are characterized by cellular inflammation within the central nervous system (CNS). The sources and consequences of this inflammation are currently not completely understood. Critical signs and mediators of CNS inflammation are reactive oxygen species (ROS) that promote inflammation. ROS originate from a variety of redox-reactive enzymes, one class of which catalyses oxidative protein folding within the endoplasmic reticulum (ER). Here, the unfolded protein response and other signalling mechanisms maintain a balance between ROS producers such as ER oxidoreductin 1α (Ero1α) and antioxidants such as glutathione peroxidase 8 (GPx8). The role of ROS production within the ER has so far not been examined in the context of MS. In this manuscript, we examined how components of the ER redox network change upon MS and experimental autoimmune encephalomyelitis (EAE). We found that unlike GPx8, Ero1α increases within both MS and EAE astrocytes, in parallel with an imbalance of other oxidases such of GPx7, and that no change was observed within neurons. This imbalance of ER redox enzymes can reduce the lifespan of astrocytes, while neurons are not affected. Therefore, Ero1α induction makes astrocytes vulnerable to oxidative stress in the MS and EAE pathologies.
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Affiliation(s)
- Samira Samtleben
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - Lucas Mina
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - Megan C Yap
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
| | - William G Branton
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, Canada
| | - Muhammad Saad Yousuf
- Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, Alberta, Canada.,UTD Pain Center, Dallas, Texas, USA
| | - Gustavo Tenorio
- Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Klaus Ballanyi
- Department of Physiology, University of Alberta, Edmonton, Alberta, Canada
| | - Fabrizio Giuliani
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, Canada
| | - Bradley J Kerr
- Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Christopher Power
- Department of Medicine (Neurology), University of Alberta, Edmonton, Alberta, Canada
| | - Thomas Simmen
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta, Edmonton, Alberta, Canada
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3
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Neurochemical Monitoring of Traumatic Brain Injury by the Combined Analysis of Plasma Beta-Synuclein, NfL, and GFAP in Polytraumatized Patients. Int J Mol Sci 2022; 23:ijms23179639. [PMID: 36077033 PMCID: PMC9456193 DOI: 10.3390/ijms23179639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/22/2022] [Accepted: 08/23/2022] [Indexed: 11/17/2022] Open
Abstract
Traumatic brain injury (TBI) represents a major determining factor of outcome in severely injured patients. However, reliable brain-damage-monitoring markers are still missing. We therefore assessed brain-specific beta-synuclein as a novel blood biomarker of synaptic damage and measured the benchmarks neurofilament light chain (NfL), as a neuroaxonal injury marker, and glial fibrillary acidic protein (GFAP), as an astroglial injury marker, in patients after polytrauma with and without TBI. Compared to healthy volunteers, plasma NfL, beta-synuclein, and GFAP were significantly increased after polytrauma. The markers demonstrated highly distinct time courses, with beta-synuclein and GFAP peaking early and NfL concentrations gradually elevating during the 10-day observation period. Correlation analyses revealed a distinct influence of the extent of extracranial hemorrhage and the severity of head injury on biomarker concentrations. A combined analysis of beta-synuclein and GFAP effectively discriminated between polytrauma patients with and without TBI, despite the comparable severity of injury. Furthermore, we found a good predictive performance for fatal outcome by employing the initial plasma concentrations of NfL, beta-synuclein, and GFAP. Our findings suggest a high diagnostic value of neuronal injury markers reflecting distinct aspects of neuronal injury for the diagnosis of TBI in the complex setting of polytrauma, especially in clinical surroundings with limited imaging opportunities.
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Marola OJ, Howell GR, Libby RT. Vascular derived endothelin receptor A controls endothelin-induced retinal ganglion cell death. Cell Death Dis 2022; 8:207. [PMID: 35429992 PMCID: PMC9013356 DOI: 10.1038/s41420-022-00985-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/13/2022] [Accepted: 03/23/2022] [Indexed: 11/29/2022]
Abstract
Endothelin (EDN, also known as ET) signaling has been suggested to be an important mediator of retinal ganglion cell (RGC) death in glaucoma. Antagonism of EDN receptors (EDNRA and EDNRB, also known as ET-A and ET-B) prevented RGC death in mouse models of chronic ocular hypertension, and intravitreal injection of EDN ligand was sufficient to drive RGC death. However, it remains unclear which cell types EDN ligands directly affect to elicit RGC death. Multiple cell types in the retina and optic nerve express EDNRA and EDNRB and thus could respond to EDN ligands in the context of glaucoma. Here, we systematically deleted Edn receptors from specific cell types to identify the critical EDN receptor mediating RGC death in vivo. Deletion of both Ednra and Ednrb from retinal neurons (including RGCs) and macroglia did not prevent RGC loss after exposure to EDN1 ligands, suggesting EDN1 ligands cause RGC death via an indirect mechanism involving a secondary cell type. Deletion of Ednra from the full body, and then specifically from vascular mural cells, prevented EDN1-induced vasoconstriction and RGC death. Together, these data suggest EDN ligands cause RGC death via a mechanism initiated by vascular mural cells. It is possible RGC death is a consequence of vascular mural cell-induced vasoconstriction and its pathological sequelae. These results highlight the potential importance of neurovascular dysfunction in glaucoma.
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He Q, Ma Y, Liu J, Zhang D, Ren J, Zhao R, Chang J, Guo ZN, Yang Y. Biological Functions and Regulatory Mechanisms of Hypoxia-Inducible Factor-1α in Ischemic Stroke. Front Immunol 2021; 12:801985. [PMID: 34966392 PMCID: PMC8710457 DOI: 10.3389/fimmu.2021.801985] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 11/26/2021] [Indexed: 12/15/2022] Open
Abstract
Ischemic stroke is caused by insufficient cerebrovascular blood and oxygen supply. It is a major contributor to death or disability worldwide and has become a heavy societal and clinical burden. To date, effective treatments for ischemic stroke are limited, and innovative therapeutic methods are urgently needed. Hypoxia inducible factor-1α (HIF-1α) is a sensitive regulator of oxygen homeostasis, and its expression is rapidly induced after hypoxia/ischemia. It plays an extensive role in the pathophysiology of stroke, including neuronal survival, neuroinflammation, angiogenesis, glucose metabolism, and blood brain barrier regulation. In addition, the spatiotemporal expression profile of HIF-1α in the brain shifts with the progression of ischemic stroke; this has led to contradictory findings regarding its function in previous studies. Therefore, unveiling the Janus face of HIF-1α and its target genes in different type of cells and exploring the role of HIF-1α in inflammatory responses after ischemia is of great importance for revealing the pathogenesis and identifying new therapeutic targets for ischemic stroke. Herein, we provide a succinct overview of the current approaches targeting HIF-1α and summarize novel findings concerning HIF-1α regulation in different types of cells within neurovascular units, including neurons, endothelial cells, astrocytes, and microglia, during the different stages of ischemic stroke. The current representative translational approaches focused on neuroprotection by targeting HIF-1α are also discussed.
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Affiliation(s)
- Qianyan He
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Yinzhong Ma
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Jie Liu
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Dianhui Zhang
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Jiaxin Ren
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Ruoyu Zhao
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - JunLei Chang
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Institute of Biomedicine and Biotechnology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Zhen-Ni Guo
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Yi Yang
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
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Han J, Hyun J, Park J, Jung S, Oh Y, Kim Y, Ryu SH, Kim SH, Jeong EI, Jo DG, Park SH, Jung YK. Aberrant role of pyruvate kinase M2 in the regulation of gamma-secretase and memory deficits in Alzheimer's disease. Cell Rep 2021; 37:110102. [PMID: 34879266 DOI: 10.1016/j.celrep.2021.110102] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 09/25/2021] [Accepted: 11/15/2021] [Indexed: 10/19/2022] Open
Abstract
Toxic amyloid beta (Aβ) species cause synaptic dysfunction and neurotoxicity in Alzheimer's disease (AD). As of yet, however, there are no reported regulators for gamma-secretase, which links a risky environment to amyloid accumulation in AD. Here, we report that pyruvate kinase M2 (PKM2) is a positive regulator of gamma-secretase under hypoxia. From a genome-wide functional screen, we identify PKM2 as a gamma-secretase activator that is highly expressed in the brains of both patients and murine models with AD. PKM2 regulates Aβ production and the amount of active gamma-secretase complex by changing the gene expression of aph-1 homolog. Hypoxia induces PKM2 expression, thereby promoting gamma-secretase activity. Moreover, transgenic expression of PKM2 in 3xTg AD model mice enhances hippocampal production of Aβ and exacerbates the impairment of spatial and recognition memory. Taken together, these findings indicate that PKM2 is an important gamma-secretase regulator that promotes Aβ production and memory impairment under hypoxia.
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Affiliation(s)
- Jonghee Han
- School of Biological Science, Seoul National University, Seoul 08826, Korea; Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Junho Hyun
- School of Biological Science, Seoul National University, Seoul 08826, Korea
| | - Jaesang Park
- School of Biological Science, Seoul National University, Seoul 08826, Korea
| | - Sunmin Jung
- School of Biological Science, Seoul National University, Seoul 08826, Korea
| | - Yoonseo Oh
- School of Biological Science, Seoul National University, Seoul 08826, Korea
| | - Youbin Kim
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul 08826, Korea
| | - Shin-Hyeon Ryu
- School of Biological Science, Seoul National University, Seoul 08826, Korea
| | - Seo-Hyun Kim
- School of Biological Science, Seoul National University, Seoul 08826, Korea
| | - Eun Il Jeong
- School of Biological Science, Seoul National University, Seoul 08826, Korea
| | - Dong-Gyu Jo
- School of Pharmacy, Sungkyunkwan University, Gyunggi-do 16419, Korea
| | - Sung-Hye Park
- Department of Pathology, Seoul National University College of Medicine, Seoul 03080, Korea
| | - Yong-Keun Jung
- School of Biological Science, Seoul National University, Seoul 08826, Korea.
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7
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Vandenberg GG, Thotakura A, Scott AL. Mitochondrial bioenergetics of astrocytes in Fragile X Syndrome: new perspectives from culture conditions and sex effects. Am J Physiol Cell Physiol 2021; 322:C125-C135. [PMID: 34817267 DOI: 10.1152/ajpcell.00130.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fragile X syndrome is a genetic disorder that is characterized by a range of cognitive and behavioural deficits, including mild-moderate intellectual disability. The disease is characterized by an X-linked mutation of the Fmr1 gene, which causes silencing of the gene coding for FMRP, a translational regulator integral for neurodevelopment. Mitochondrial dysfunction has been recently associated with FXS, with reports of increases in oxidative stress markers, reactive oxygen species, and lipid peroxidation being present in brain tissue. Astrocytes, a prominent glial cell within the CNS, plays a large role in regulating oxidative homeostasis within the developing brain and dysregulation of astrocyte redox balance in FXS may contribute to oxidative stress. Astrocyte function and mitochondrial bioenergetics is significantly influenced by oxygen availability as well as circulating sex hormones; yet these parameters are rarely considered during in vitro experimentation. Given that the brain normally develops in a range of hypoxic conditions and FXS is a sex-linked genetic disorder, we investigated how different oxygen levels (normoxic versus hypoxic) and biological sex affected mitochondrial bioenergetics of astrocytes in FXS. Our results show demonstrate that both mitochondrial respiration capacity and reactive oxygen species emission are altered with Fmr1 deletion in astrocytes and these changes were dependent upon both sexual dimorphism and oxygen availability.
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Affiliation(s)
- Gregory G Vandenberg
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Aasritha Thotakura
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Angela L Scott
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
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8
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Xu C, Dai Y, Bai J, Ren B, Xu J, Gao F, Wang L, Zhang W, Wang R. 17β-oestradiol alleviates endoplasmic reticulum stress injury induced by chronic cerebral hypoperfusion through the Haemoglobin/HIF 1α signalling pathway in ovariectomized rats. Neurochem Int 2021; 148:105119. [PMID: 34224805 DOI: 10.1016/j.neuint.2021.105119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 06/04/2021] [Accepted: 06/27/2021] [Indexed: 11/28/2022]
Abstract
Endoplasmic reticulum stress (ERS) is known to be an essential target in protecting against ischaemic brain injury. In this study, using a vascular dementia (VaD) animal model induced by bilateral common carotid artery occlusion (BCCAO), we evaluated the effect and mechanism of 17β-oestradiol (E2) against VaD by inhibiting ERS at the early stage (14 d, 21 d, 28 d) and late stage (3 m) after BCCAO in the hippocampal CA1 region of ovariectomized rats. The results showed that the activation of the PERK-eIF2α-ATF4-CHOP axis, a typical ERS pathway, was significantly increased at the early and late stages after BCCAO. JNK (c-Jun N-terminal kinase)-cJun, a pro-death pathway, also displayed the same pattern as the ERS axis. E2 treatment profoundly suppressed the impairments caused by BCCAO. Further mechanistic studies revealed that cerebral blood flow (CBF) was sharply decreased at 14 d and returned to the normal level at 21 d after BCCAO. E2 could not change CBF, while it unexpectedly enhanced the ability to carry oxygen. This is evidenced by the fact that the protein expression of haemoglobin α/β (Hα/β), an oxygen carrier, robustly increased at BCCAO 21 d and 3 m after E2 treatment. The oxygen carrier increased strongly after 21 d and 3 m of BCCAO treated with E2. Moreover, E2 correspondingly enhanced the protein expression of hypoxia-inducible factor 1α (HIF 1α) in both the early and late stage after BCCAO in the hippocampal CA1 region. Finally, E2 administration markedly decreased the activities of caspase-8, caspase-3, and caspase-12 and increased the number of NeuN-positive cells. These findings suggest that E2 serves as a neuroprotectant to alleviate VaD by suppressing ERS injury involving the haemoglobin/HIF 1α signalling pathway.
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Affiliation(s)
- Chao Xu
- Neurobiology Institute, School of Public Health, North China University of Science and Technology, International Science & Technology Cooperation Base of Geriatric Medicine of China, Tangshan, Hebei, 063210, China; Dementia and Dyscognitive Key Lab, Tangshan, Hebei, 063000, China
| | - Yongxin Dai
- Neurobiology Institute, School of Public Health, North China University of Science and Technology, International Science & Technology Cooperation Base of Geriatric Medicine of China, Tangshan, Hebei, 063210, China; Dementia and Dyscognitive Key Lab, Tangshan, Hebei, 063000, China
| | - Jing Bai
- Neurobiology Institute, School of Public Health, North China University of Science and Technology, International Science & Technology Cooperation Base of Geriatric Medicine of China, Tangshan, Hebei, 063210, China; Dementia and Dyscognitive Key Lab, Tangshan, Hebei, 063000, China; School Basic Medical Sciences, North China University of Science and Technology, Tangshan, Hebei, 063210, China
| | - Bo Ren
- School Basic Medical Sciences, North China University of Science and Technology, Tangshan, Hebei, 063210, China
| | - Jing Xu
- Neurobiology Institute, School of Public Health, North China University of Science and Technology, International Science & Technology Cooperation Base of Geriatric Medicine of China, Tangshan, Hebei, 063210, China; Dementia and Dyscognitive Key Lab, Tangshan, Hebei, 063000, China; School Basic Medical Sciences, North China University of Science and Technology, Tangshan, Hebei, 063210, China
| | - Fujia Gao
- Neurobiology Institute, School of Public Health, North China University of Science and Technology, International Science & Technology Cooperation Base of Geriatric Medicine of China, Tangshan, Hebei, 063210, China; Dementia and Dyscognitive Key Lab, Tangshan, Hebei, 063000, China
| | - Lu Wang
- Neurobiology Institute, School of Public Health, North China University of Science and Technology, International Science & Technology Cooperation Base of Geriatric Medicine of China, Tangshan, Hebei, 063210, China; Dementia and Dyscognitive Key Lab, Tangshan, Hebei, 063000, China
| | - Wenli Zhang
- Neurobiology Institute, School of Public Health, North China University of Science and Technology, International Science & Technology Cooperation Base of Geriatric Medicine of China, Tangshan, Hebei, 063210, China; Dementia and Dyscognitive Key Lab, Tangshan, Hebei, 063000, China
| | - Ruimin Wang
- Neurobiology Institute, School of Public Health, North China University of Science and Technology, International Science & Technology Cooperation Base of Geriatric Medicine of China, Tangshan, Hebei, 063210, China; Dementia and Dyscognitive Key Lab, Tangshan, Hebei, 063000, China; School Basic Medical Sciences, North China University of Science and Technology, Tangshan, Hebei, 063210, China.
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9
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Park J, Lee M, Kim M, Moon S, Kim S, Kim S, Koh SH, Kim YM, Choi YK. Prophylactic role of Korean red ginseng in astrocytic mitochondrial biogenesis through HIF-1α. J Ginseng Res 2021; 46:408-417. [PMID: 35600778 PMCID: PMC9120627 DOI: 10.1016/j.jgr.2021.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 07/01/2021] [Accepted: 07/07/2021] [Indexed: 01/12/2023] Open
Abstract
Background Methods Results Conclusion
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VEGF/VEGFR-2 system exerts neuroprotection against Phoneutria nigriventer spider envenomation through PI3K-AKT-dependent pathway. Toxicon 2020; 185:76-90. [PMID: 32649934 DOI: 10.1016/j.toxicon.2020.06.019] [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: 08/31/2019] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 01/19/2023]
Abstract
This study was undertaken to elucidate why VEGF/VEGFR-2 is elevated in the hippocampus of rats injected with Phoneutria nigriventer spider venom (PNV). PNV delays Na+ channels inactivation; blocks Ca2+ and K+ channels, increases glutamate release, causes blood-brain breakdown (BBBb), brain edema and severe excitotoxicity. Analytical FT-IR spectroscopy showed profound alteration in molecular biochemical state, with evidences for VEGFR-2 (KDR/Flk-1) signaling mediation. By blocking VEGF/VEGFR-2 binding via pre-treatment with itraconazole we demonstrated that animals' condition was deteriorated soon at 1-2 h post-PNV exposure concurrently with decreased expression of VEGF, BBB-associated proteins, ZO-1, β-catenin, laminin, P-gp (P-glycoprotein), Neu-N (neuron's viability marker) and MAPKphosphorylated-p38, while phosphorylated-ERK and Src pathways were increased. At 5 h and coinciding with incipient signs of animals' recuperation, the proteins associated with protection (HIF-1α, VEGF, VEGFR-1, VEGFR-2, Neu-N, occludin, β-catenin, laminin, P-gp efflux protein, phosphorylated-p38) increased thus indicating p38 pathway activation together with paracellular route strengthening. However, the BBB transcellular trafficking and caspase-3 increased (pro-apoptotic pathway activation). At 24 h, the transcellular route reestablished physiological state but the pro-survival pathway PI3K/(p-Akt) dropped in animals underwent VEGF/VEGFR-2 binding inhibition, whereas it was significantly activated at matched interval in PNV group without prior itraconazole; these results demonstrate impaired VEGF' survival effects at 24 h. The inhibition of VEGF/VEGFR-2 binding identified 5 h as turning point at which multi-level dynamic interplay was elicited to reverse hippocampal damage. Collectively, the data confirmed VEGFR-2 signaling via serine-threonine kinase Akt as neuroprotective pathway against PNV-induced damage. Further studies are needed to elucidate mechanisms underlying PNV effects.
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11
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Kery R, Chen APF, Kirschen GW. Genetic targeting of astrocytes to combat neurodegenerative disease. Neural Regen Res 2020; 15:199-211. [PMID: 31552885 PMCID: PMC6905329 DOI: 10.4103/1673-5374.265541] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Astrocytes, glial cells that interact extensively with neurons and other support cells throughout the central nervous system, have recently come under the spotlight for their potential contribution to, or potential regenerative role in a host of neurodegenerative disorders. It is becoming increasingly clear that astrocytes, in concert with microglial cells, activate intrinsic immunological pathways in the setting of neurodegenerative injury, although the direct and indirect consequences of such activation are still largely unknown. We review the current literature on the astrocyte’s role in several neurodegenerative diseases, as well as highlighting recent advances in genetic manipulation of astrocytes that may prove critical to modulating their response to neurological injury, potentially combatting neurodegenerative damage.
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Affiliation(s)
- Rachel Kery
- Medical Scientist Training Program (MSTP), Stony Brook Medicine; Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Allen P F Chen
- Medical Scientist Training Program (MSTP), Stony Brook Medicine; Department of Neurobiology & Behavior, Stony Brook University, Stony Brook, NY, USA
| | - Gregory W Kirschen
- Medical Scientist Training Program (MSTP), Stony Brook Medicine, Stony Brook, NY, USA
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12
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E Silva LFS, Brito MD, Yuzawa JMC, Rosenstock TR. Mitochondrial Dysfunction and Changes in High-Energy Compounds in Different Cellular Models Associated to Hypoxia: Implication to Schizophrenia. Sci Rep 2019; 9:18049. [PMID: 31792231 PMCID: PMC6889309 DOI: 10.1038/s41598-019-53605-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 10/24/2019] [Indexed: 02/06/2023] Open
Abstract
Schizophrenia (SZ) is a multifactorial mental disorder, which has been associated with a number of environmental factors, such as hypoxia. Considering that numerous neural mechanisms depends on energetic supply (ATP synthesis), the maintenance of mitochondrial metabolism is essential to keep cellular balance and survival. Therefore, in the present work, we evaluated functional parameters related to mitochondrial function, namely calcium levels, mitochondrial membrane potential, redox homeostasis, high-energy compounds levels and oxygen consumption, in astrocytes from control (Wistar) and Spontaneously Hypertensive Rats (SHR) animals exposed both to chemical and gaseous hypoxia. We show that astrocytes after hypoxia presented depolarized mitochondria, disturbances in Ca2+ handling, destabilization in redox system and alterations in ATP, ADP, Pyruvate and Lactate levels, in addition to modification in NAD+/NADH ratio, and Nfe2l2 and Nrf1 expression. Interestingly, intrauterine hypoxia also induced augmentation in mitochondrial biogenesis and content. Altogether, our data suggest that hypoxia can induce mitochondrial deregulation and a decrease in energy metabolism in the most prevalent cell type in the brain, astrocytes. Since SHR are also considered an animal model of SZ, our results can likewise be related to their phenotypic alterations and, therefore, our work also allow an increase in the knowledge of this burdensome disorder.
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Kim Y, Park J, Choi YK. The Role of Astrocytes in the Central Nervous System Focused on BK Channel and Heme Oxygenase Metabolites: A Review. Antioxidants (Basel) 2019; 8:antiox8050121. [PMID: 31060341 PMCID: PMC6562853 DOI: 10.3390/antiox8050121] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 04/25/2019] [Accepted: 05/02/2019] [Indexed: 12/13/2022] Open
Abstract
Astrocytes outnumber neurons in the human brain, and they play a key role in numerous functions within the central nervous system (CNS), including glutamate, ion (i.e., Ca2+, K+) and water homeostasis, defense against oxidative/nitrosative stress, energy storage, mitochondria biogenesis, scar formation, tissue repair via angiogenesis and neurogenesis, and synapse modulation. After CNS injury, astrocytes communicate with surrounding neuronal and vascular systems, leading to the clearance of disease-specific protein aggregates, such as β-amyloid, and α-synuclein. The astrocytic big conductance K+ (BK) channel plays a role in these processes. Recently, potential therapeutic agents that target astrocytes have been tested for their potential to repair the brain. In this review, we discuss the role of the BK channel and antioxidant agents such as heme oxygenase metabolites following CNS injury. A better understanding of the cellular and molecular mechanisms of astrocytes’ functions in the healthy and diseased brains will greatly contribute to the development of therapeutic approaches following CNS injury, such as Alzheimer’s disease, Parkinson’s disease, and stroke.
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Affiliation(s)
- Yonghee Kim
- Department of Integrative Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea.
| | - Jinhong Park
- Department of Integrative Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea.
| | - Yoon Kyung Choi
- Department of Integrative Bioscience and Biotechnology, Konkuk University, Seoul 05029, Korea.
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14
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Wu Q, Wu WS, Su L, Zheng X, Wu WY, Santambrogio P, Gou YJ, Hao Q, Wang PN, Li YR, Zhao BL, Nie G, Levi S, Chang YZ. Mitochondrial Ferritin Is a Hypoxia-Inducible Factor 1α-Inducible Gene That Protects from Hypoxia-Induced Cell Death in Brain. Antioxid Redox Signal 2019; 30:198-212. [PMID: 29402144 DOI: 10.1089/ars.2017.7063] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Aims: Mitochondrial ferritin (protein [FtMt]) is preferentially expressed in cell types of high metabolic activity and oxygen consumption, which is consistent with its role of sequestering iron and preventing oxygen-derived redox damage. As of yet, the mechanisms of FtMt regulation and the protection FtMt affords remain largely unknown. Results: Here, we report that hypoxia-inducible factor 1α (HIF-1α) can upregulate FtMt expression. We verify one functional hypoxia-response element (HRE) in the positive regulatory region and two HREs possessing HIF-1α binding activity in the minimal promoter region of the human FTMT gene. We also demonstrate that FtMt can alleviate hypoxia-induced brain cell death by sequestering uncommitted iron, whose levels increase with hypoxia in these cells. Innovation: In the absence of FtMt, this catalytic metal excess catalyzes the production of cytotoxic reactive oxygen species. Conclusion: Thus, the cell ability to increase expression of FtMt during hypoxia may be a skill to avoid tissue damage derived from oxygen limitation.
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Affiliation(s)
- Qiong Wu
- 1 Laboratory of Molecular Iron Metabolism, The Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University , Shijiazhuang, China .,2 Division of Neuroscience, San Raffaele Scientific Institute , Milano, Italy .,3 College of Basic Medicine, Hebei University of Chinese Medicine , Shijiazhuang, China .,4 Department of Clinical Laboratory, The Third Hospital of Hebei Medical University , Shijiazhuang, China
| | - Wen-Shuang Wu
- 1 Laboratory of Molecular Iron Metabolism, The Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University , Shijiazhuang, China .,3 College of Basic Medicine, Hebei University of Chinese Medicine , Shijiazhuang, China .,4 Department of Clinical Laboratory, The Third Hospital of Hebei Medical University , Shijiazhuang, China
| | - Lin Su
- 1 Laboratory of Molecular Iron Metabolism, The Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University , Shijiazhuang, China
| | - Xin Zheng
- 1 Laboratory of Molecular Iron Metabolism, The Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University , Shijiazhuang, China
| | - Wen-Yue Wu
- 1 Laboratory of Molecular Iron Metabolism, The Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University , Shijiazhuang, China
| | - Paolo Santambrogio
- 2 Division of Neuroscience, San Raffaele Scientific Institute , Milano, Italy
| | - Yu-Jing Gou
- 1 Laboratory of Molecular Iron Metabolism, The Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University , Shijiazhuang, China
| | - Qian Hao
- 1 Laboratory of Molecular Iron Metabolism, The Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University , Shijiazhuang, China
| | - Pei-Na Wang
- 1 Laboratory of Molecular Iron Metabolism, The Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University , Shijiazhuang, China
| | - Ya-Ru Li
- 1 Laboratory of Molecular Iron Metabolism, The Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University , Shijiazhuang, China
| | - Bao-Lu Zhao
- 1 Laboratory of Molecular Iron Metabolism, The Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University , Shijiazhuang, China
| | - Guangjun Nie
- 5 CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology , Beijing, China
| | - Sonia Levi
- 2 Division of Neuroscience, San Raffaele Scientific Institute , Milano, Italy .,6 Vita-Salute San Raffaele University , Milano, Italy
| | - Yan-Zhong Chang
- 1 Laboratory of Molecular Iron Metabolism, The Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University , Shijiazhuang, China
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15
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Baez-Jurado E, Rincón-Benavides MA, Hidalgo-Lanussa O, Guio-Vega G, Ashraf GM, Sahebkar A, Echeverria V, Garcia-Segura LM, Barreto GE. Molecular mechanisms involved in the protective actions of Selective Estrogen Receptor Modulators in brain cells. Front Neuroendocrinol 2019; 52:44-64. [PMID: 30223003 DOI: 10.1016/j.yfrne.2018.09.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/09/2018] [Accepted: 09/12/2018] [Indexed: 02/06/2023]
Abstract
Synthetic selective modulators of the estrogen receptors (SERMs) have shown to protect neurons and glial cells against toxic insults. Among the most relevant beneficial effects attributed to these compounds are the regulation of inflammation, attenuation of astrogliosis and microglial activation, prevention of excitotoxicity and as a consequence the reduction of neuronal cell death. Under pathological conditions, the mechanism of action of the SERMs involves the activation of estrogen receptors (ERs) and G protein-coupled receptor for estrogens (GRP30). These receptors trigger neuroprotective responses such as increasing the expression of antioxidants and the activation of kinase-mediated survival signaling pathways. Despite the advances in the knowledge of the pathways activated by the SERMs, their mechanism of action is still not entirely clear, and there are several controversies. In this review, we focused on the molecular pathways activated by SERMs in brain cells, mainly astrocytes, as a response to treatment with raloxifene and tamoxifen.
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Affiliation(s)
- E Baez-Jurado
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | - M A Rincón-Benavides
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | - O Hidalgo-Lanussa
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | - G Guio-Vega
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia
| | - G M Ashraf
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - A Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Neurogenic Inflammation Research Center, Mashhad University of Medical Sciences, Mashhad, Iran; School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - V Echeverria
- Universidad San Sebastián, Fac. Cs de la Salud, Lientur 1457, Concepción 4080871, Chile; Research & Development Service, Bay Pines VA Healthcare System, Bay Pines, FL 33744, USA
| | - L M Garcia-Segura
- Instituto Cajal, CSIC, Madrid, Spain; Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable (CIBERFES), Instituto de Salud Carlos III, Madrid, Spain
| | - G E Barreto
- Departamento de Nutrición y Bioquímica, Facultad de Ciencias, Pontificia Universidad Javeriana, Bogotá D.C., Colombia; Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile.
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16
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Ostrowski RP, Zhang JH. The insights into molecular pathways of hypoxia-inducible factor in the brain. J Neurosci Res 2018; 98:57-76. [PMID: 30548473 DOI: 10.1002/jnr.24366] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/16/2018] [Accepted: 11/20/2018] [Indexed: 12/12/2022]
Abstract
The objectives of this present work were to review recent developments on the role of hypoxia-inducible factor (HIF) in the survival of cells under normoxic versus hypoxic and inflammatory brain conditions. The dual nature of HIF effects appears well established, based on the accumulated evidence of HIF playing both the role of adaptive factor and mediator of cell demise. Cellular HIF responses depend on pathophysiological conditions, developmental phase, comorbidities, and administered medications. In addition, HIF-1α and HIF-2α actions may vary in the same tissues. The multiple roles of HIF in stem cells are emerging. HIF not only regulates expression of target genes and thereby influences resultant protein levels but also contributes to epigenetic changes that may reciprocally provide feedback regulations loops. These HIF-dependent alterations in neurological diseases and its responses to treatments in vivo need to be examined alongside with a functional status of subjects involved in such studies. The knowledge of HIF pathways might be helpful in devising HIF-mimetics and modulating drugs, acting on the molecular level to improve clinical outcomes, as exemplified here by clinical and experimental data of selected brain diseases, occasionally corroborated by the data from disorders of other organs. Because of complex role of HIF in brain injuries, prospective therapeutic interventions need to differentially target HIF responses depending on their roles in the molecular mechanisms of neurologic diseases.
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Affiliation(s)
- Robert P Ostrowski
- Department of Experimental and Clinical Neuropathology, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
| | - John H Zhang
- Departments of Anesthesiology and Physiology, School of Medicine, Loma Linda University, Loma Linda, California
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17
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Chen L, Wang L, Zhuo Q, Zhang Q, Chen F, Li L, Lin L. Effect of Shenmai injection on cognitive function after cardiopulmonary bypass in cardiac surgical patients: a randomized controlled trial. BMC Anesthesiol 2018; 18:142. [PMID: 30309327 PMCID: PMC6182819 DOI: 10.1186/s12871-018-0604-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 09/24/2018] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Postoperative cognitive dysfunction (POCD) is a common complication after cardiac surgery that influences the clinical outcomes and quality of life of patients. This study aimed to evaluate the effects of Shenmai injection (SMI) on POCD of patients who underwent cardiac valve replacement under cardiopulmonary bypass (CPB). METHODS This prospective, randomized, controlled trial was conducted from September 2014 to January 2017. Eighty-eight patients receiving cardiac valve replacement under CPB were randomized into the control (C) or the SMI (S) group. SMI (0.6 mL/kg) was administered intravenously from the time of anesthesia induction to the beginning of CPB. Cognitive function was assessed at 3 days before surgery and 3 days, 7 days, and 1 month after surgery using the Beijing version of the Montreal Cognitive Assessment (MoCA-BJ) score. The serum levels of neuroglobin (Ngb), hypoxia-inducible factor-1α (HIF-1α), and neuron-specific enolase (NSE) were measured at 30 min after induction (T0), immediately after the endonasal temperature rewarmed to 36 °C (T1), and 1 h (T2), 6 h (T3), 24 h (T4), 48 h (T5), and 72 h (T6) after CPB. RESULTS Compared with the baseline values at T0, the serum Ngb levels in group C were significantly decreased at T1-2 and then increased at T3-6, while the levels in group S were decreased at T1-2 and increased at T4-6, compared to group C (p < 0.05). The serum HIF-1α levels at T1-4 and the serum NSE levels at T1-6 were significantly increased in both groups (p < 0.05). The serum levels of Ngb at T3, HIF-1α at T1-3, and NSE at T3-4,6 were lower in group S, compared to group C (p < 0.01). The MoCA-BJ scores were decreased at 3 and 7 days after surgery in both groups, and the MoCA-BJ scores in group S were higher than those in group C at 3 and 7 days after surgery (p < 0.01). CONCLUSION Cognitive function is impaired postoperatively in patients who have undergone cardiac valve replacement under CPB. In addition, treatment with the traditional Chinese medicine SMI decreases the serum levels of Ngb, HIF-1α, and NSE as well as attenuates cognitive dysfunction. TRIAL REGISTRATION This trial was registered with Clinicaltrials.gov as ChiCTR-TRC-14004373 on March 11, 2014.
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Affiliation(s)
- Lei Chen
- Department of Anesthesiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Liangrong Wang
- Department of Anesthesiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Qian Zhuo
- Wenzhou People's Hospital, Wenzhou, Zhejiang Province, China
| | - Qiong Zhang
- Department of Anesthesiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Feifei Chen
- Department of Anesthesiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Liling Li
- Department of Anesthesiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Lina Lin
- Department of Anesthesiology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China.
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18
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Chen R, Lai UH, Zhu L, Singh A, Ahmed M, Forsyth NR. Reactive Oxygen Species Formation in the Brain at Different Oxygen Levels: The Role of Hypoxia Inducible Factors. Front Cell Dev Biol 2018; 6:132. [PMID: 30364203 PMCID: PMC6192379 DOI: 10.3389/fcell.2018.00132] [Citation(s) in RCA: 161] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 09/21/2018] [Indexed: 12/11/2022] Open
Abstract
Hypoxia inducible factor (HIF) is the master oxygen sensor within cells and is central to the regulation of cell responses to varying oxygen levels. HIF activation during hypoxia ensures optimum ATP production and cell integrity, and is associated both directly and indirectly with reactive oxygen species (ROS) formation. HIF activation can either reduce ROS formation by suppressing the function of mitochondrial tricarboxylic acid cycle (TCA cycle), or increase ROS formation via NADPH oxidase (NOX), a target gene of HIF pathway. ROS is an unavoidable consequence of aerobic metabolism. In normal conditions (i.e., physioxia), ROS is produced at minimal levels and acts as a signaling molecule subject to the dedicated balance between ROS production and scavenging. Changes in oxygen concentrations affect ROS formation. When ROS levels exceed defense mechanisms, ROS causes oxidative stress. Increased ROS levels can also be a contributing factor to HIF stabilization during hypoxia and reoxygenation. In this review, we systemically review HIF activation and ROS formation in the brain during hypoxia and hypoxia/reoxygenation. We will then explore the literature describing how changes in HIF levels might provide pharmacological targets for effective ischaemic stroke treatment. HIF accumulation in the brain via HIF prolyl hydroxylase (PHD) inhibition is proposed as an effective therapy for ischaemia stroke due to its antioxidation and anti-inflammatory properties in addition to HIF pro-survival signaling. PHD is a key regulator of HIF levels in cells. Pharmacological inhibition of PHD increases HIF levels in normoxia (i.e., at 20.9% O2 level). Preconditioning with HIF PHD inhibitors show a neuroprotective effect in both in vitro and in vivo ischaemia stroke models, but post-stroke treatment with PHD inhibitors remains debatable. HIF PHD inhibition during reperfusion can reduce ROS formation and activate a number of cellular survival pathways. Given agents targeting individual molecules in the ischaemic cascade (e.g., antioxidants) fail to be translated in the clinic setting, thus far, HIF pathway targeting and thereby impacting entire physiological networks is a promising drug target for reducing the adverse effects of ischaemic stroke.
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Affiliation(s)
- Ruoli Chen
- School of Pharmacy, Keele University, Staffordshire, United Kingdom.,Institute for Science and Technology in Medicine, Keele University, Staffordshire, United Kingdom
| | - U Hin Lai
- School of Pharmacy, Keele University, Staffordshire, United Kingdom
| | - Lingling Zhu
- Department of Brain Protection and Plasticity, Institute of Basic Medical Sciences, Beijing, China
| | - Ayesha Singh
- School of Pharmacy, Keele University, Staffordshire, United Kingdom.,Institute for Science and Technology in Medicine, Keele University, Staffordshire, United Kingdom
| | - Muhammad Ahmed
- Institute for Science and Technology in Medicine, Keele University, Staffordshire, United Kingdom.,College of Pharmacy, University of Mosul, Mosul, Iraq
| | - Nicholas R Forsyth
- Institute for Science and Technology in Medicine, Keele University, Staffordshire, United Kingdom
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19
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Salman MM, Kitchen P, Woodroofe MN, Bill RM, Conner AC, Heath PR, Conner MT. Transcriptome Analysis of Gene Expression Provides New Insights into the Effect of Mild Therapeutic Hypothermia on Primary Human Cortical Astrocytes Cultured under Hypoxia. Front Cell Neurosci 2017; 11:386. [PMID: 29311824 PMCID: PMC5735114 DOI: 10.3389/fncel.2017.00386] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 11/20/2017] [Indexed: 01/02/2023] Open
Abstract
Hypothermia is increasingly used as a therapeutic measure to treat brain injury. However, the cellular mechanisms underpinning its actions are complex and are not yet fully elucidated. Astrocytes are the most abundant cell type in the brain and are likely to play a critical role. In this study, transcriptional changes and the protein expression profile of human primary cortical astrocytes cultured under hypoxic conditions for 6 h were investigated. Cells were treated either with or without a mild hypothermic intervention 2 h post-insult to mimic the treatment of patients following traumatic brain injury (TBI) and/or stroke. Using human gene expression microarrays, 411 differentially expressed genes were identified following hypothermic treatment of astrocytes following a 2 h hypoxic insult. KEGG pathway analysis indicated that these genes were mainly enriched in the Wnt and p53 signaling pathways, which were inhibited following hypothermic intervention. The expression levels of 168 genes involved in Wnt signaling were validated by quantitative real-time-PCR (qPCR). Among these genes, 10 were up-regulated and 32 were down-regulated with the remainder unchanged. Two of the differentially expressed genes (DEGs), p38 and JNK, were selected for validation at the protein level using cell based ELISA. Hypothermic intervention significantly down-regulated total protein levels for the gene products of p38 and JNK. Moreover, hypothermia significantly up-regulated the phosphorylated (activated) forms of JNK protein, while downregulating phosphorylation of p38 protein. Within the p53 signaling pathway, 35 human apoptosis-related proteins closely associated with Wnt signaling were investigated using a Proteome Profiling Array. Hypothermic intervention significantly down-regulated 18 proteins, while upregulating one protein, survivin. Hypothermia is a complex intervention; this study provides the first detailed longitudinal investigation at the transcript and protein expression levels of the molecular effects of therapeutic hypothermic intervention on hypoxic human primary cortical astrocytes. The identified genes and proteins are targets for detailed functional studies, which may help to develop new treatments for brain injury based on an in-depth mechanistic understanding of the astrocytic response to hypoxia and/or hypothermia.
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Affiliation(s)
- Mootaz M Salman
- Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, United Kingdom
| | - Philip Kitchen
- Institute of Clinical Sciences, University of Birmingham, Birmingham, United Kingdom
| | - M Nicola Woodroofe
- Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, United Kingdom
| | - Roslyn M Bill
- School of Life and Health Sciences, Aston University, Birmingham, United Kingdom
| | - Alex C Conner
- Institute of Clinical Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Paul R Heath
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Matthew T Conner
- Research Institute of Health Sciences, Wolverhampton School of Sciences, University of Wolverhampton, Wolverhampton, United Kingdom
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20
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Kardos J, Héja L, Jemnitz K, Kovács R, Palkovits M. The nature of early astroglial protection-Fast activation and signaling. Prog Neurobiol 2017; 153:86-99. [PMID: 28342942 DOI: 10.1016/j.pneurobio.2017.03.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/22/2016] [Accepted: 03/05/2017] [Indexed: 12/14/2022]
Abstract
Our present review is focusing on the uniqueness of balanced astroglial signaling. The balance of excitatory and inhibitory signaling within the CNS is mainly determined by sharp synaptic transients of excitatory glutamate (Glu) and inhibitory γ-aminobutyrate (GABA) acting on the sub-second timescale. Astroglia is involved in excitatory chemical transmission by taking up i) Glu through neurotransmitter-sodium transporters, ii) K+ released due to presynaptic action potential generation, and iii) water keeping osmotic pressure. Glu uptake-coupled Na+ influx may either ignite long-range astroglial Ca2+ transients or locally counteract over-excitation via astroglial GABA release and increased tonic inhibition. Imbalance of excitatory and inhibitory drives is associated with a number of disease conditions, including prevalent traumatic and ischaemic injuries or the emergence of epilepsy. Therefore, when addressing the potential of early therapeutic intervention, astroglial signaling functions combating progress of Glu excitotoxicity is of critical importance. We suggest, that excitotoxicity is linked primarily to over-excitation induced by the impairment of astroglial Glu uptake and/or GABA release. Within this framework, we discuss the acute alterations of Glu-cycling and metabolism and conjecture the therapeutic promise of regulation. We also confer the role played by key carrier proteins and enzymes as well as their interplay at the molecular, cellular, and organ levels. Moreover, based on our former studies, we offer potential prospect on the emerging theme of astroglial succinate sensing in course of Glu excitotoxicity.
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Affiliation(s)
- Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Hungary.
| | - László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Hungary
| | - Katalin Jemnitz
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Hungary
| | - Richárd Kovács
- Institute of Neurophysiology, Charité - Universitätsmedizin, Berlin, Germany
| | - Miklós Palkovits
- Human Brain Tissue Bank and Laboratory, Semmelweis University, Budapest, Hungary
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21
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Ramljak S, Herlyn H, Zerr I. Cellular Prion Protein (PrP c) and Hypoxia: True to Each Other in Good Times and in Bad, in Sickness, and in Health. Front Cell Neurosci 2016; 10:292. [PMID: 28066187 PMCID: PMC5165248 DOI: 10.3389/fncel.2016.00292] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 12/05/2016] [Indexed: 12/20/2022] Open
Abstract
The cellular prion protein (PrPc) and hypoxia appear to be tightly intertwined. Beneficial effects of PrPc on neuronal survival under hypoxic conditions such as focal cerebral ischemia are strongly supported. Conversely, increasing evidence indicates detrimental effects of increased PrPc expression on cancer progression, another condition accompanied by low oxygen tensions. A switch between anaerobic and aerobic metabolism characterizes both conditions. A cellular process that might unite both is glycolysis. Putative role of PrPc in stimulation of glycolysis in times of need is indeed thought provoking. A significance of astrocytic PrPc expression for neuronal survival under hypoxic conditions and possible association of PrPc with the astrocyte-neuron lactate shuttle is considered. We posit PrPc-induced lactate production via transactivation of lactate dehydrogenase A by hypoxia inducible factor 1α as an important factor for survival of both neurons and tumor cells in hypoxic microenvironment. Concomitantly, we discuss a cross-talk between Wnt/β-catenin and PI3K/Akt signaling pathways in executing PrPc-induced activation of glycolysis. Finally, we would like to emphasize that we see a great potential in joining expertise from both fields, neuroscience and cancer research in revealing the mechanisms underlying hypoxia-related pathologies. PrPc may prove focal point for future research.
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Affiliation(s)
| | - Holger Herlyn
- Institute of Anthropology, Johannes Gutenberg University of Mainz Mainz, Germany
| | - Inga Zerr
- Department of Neurology, University Medical Center Göttingen and German Center for Neurodegenerative Diseases Göttingen, Germany
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22
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Neonatal anoxia leads to time dependent progression of mitochondrial linked apoptosis in rat cortex and associated long term sensorimotor deficits. Int J Dev Neurosci 2016; 52:55-65. [DOI: 10.1016/j.ijdevneu.2016.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 04/21/2016] [Accepted: 05/12/2016] [Indexed: 01/30/2023] Open
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23
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Wang P, Li L, Zhang Z, Kan Q, Gao F, Chen S. Time-dependent activity of Na+/H+ exchanger isoform 1 and homeostasis of intracellular pH in astrocytes exposed to CoCl2 treatment. Mol Med Rep 2016; 13:4443-50. [PMID: 27035646 DOI: 10.3892/mmr.2016.5067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 02/11/2016] [Indexed: 11/06/2022] Open
Abstract
Hypoxia causes injury to the central nervous system during stroke and has significant effects on pH homeostasis. Na+/H+ exchanger isoform 1 (NHE1) is important in the mechanisms of hypoxia and intracellular pH (pHi) homeostasis. As a well-established hypoxia-mimetic agent, CoCl2 stabilizes and increases the expression of hypoxia inducible factor‑1α (HIF-1α), which regulates several genes involved in pH balance, including NHE1. However, it is not fully understood whether NHE1 is activated in astrocytes under CoCl2 treatment. In the current study, pHi and NHE activity were analyzed using the pHi‑sensitive dye BCECF‑AM. Using cariporide (an NHE1‑specific inhibitor) and EIPA (an NHE nonspecific inhibitor), the current study demonstrated that it was NHE1, not the other NHE isoforms, that was important in regulating pHi homeostasis in astrocytes during CoCl2 treatment. Additionally, the present study observed that, during the early period of CoCl2 treatment (the first 2 h), NHE1 activity and pHi dropped immediately, and NHE1 mRNA expression was reduced compared with control levels, whereas expression levels of the NHE1 protein had not yet changed. In the later period of CoCl2 treatment, NHE1 activity and pHi significantly increased compared with the control levels, as did the mRNA and protein expression levels of NHE1. Furthermore, the cell viability and injury of astrocytes was not changed during the initial 8 h of CoCl2 treatment; their deterioration was associated with the higher levels of pHi and NHE1 activity. The current study concluded that NHE1 activity and pHi homeostasis are regulated by CoCl2 treatment in a time-dependent manner in astrocytes, and may be responsible for the changes in cell viability and injury observed under hypoxia-mimetic conditions induced by CoCl2 treatment.
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Affiliation(s)
- Peng Wang
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Ling Li
- Department of Palliative and Hospice Care, The Ninth People's Hospital of Zhengzhou, Zhengzhou, Henan 450053, P.R. China
| | - Zhenxiang Zhang
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Quancheng Kan
- Clinical Pharmacology Base, Department of Infectious Disease, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Feng Gao
- Department of Neuroimmunology, Henan Academy of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Suyan Chen
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
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Wang P, Li L, Zhang Z, Kan Q, Chen S, Gao F. Time-dependent homeostasis between glucose uptake and consumption in astrocytes exposed to CoCl₂ treatment. Mol Med Rep 2016; 13:2909-17. [PMID: 26847382 DOI: 10.3892/mmr.2016.4873] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 01/11/2016] [Indexed: 11/06/2022] Open
Abstract
Hypoxia has been implicated in the pathology of the central nervous system during stroke. It also has a significant effect on the regulation of glucose transporters (GLUTs), and homeostasis between glucose uptake and consumption. CoCl2 is a hypoxia‑mimetic agent, and thus stabilizes the hypoxia‑inducible factor 1α (HIF‑1α) subunit and regulates GLUT genes. GLUT‑1 and GLUT‑3 are the most common isoforms of the GLUT family present in the brain, with the former primarily expressed in astrocytes and the latter in neurons under physiological conditions. However, it remains controversial whether GLUT‑3 is expressed in astrocytes. Additionally, it is unclear whether the regulation of GLUT‑1 and GLUT‑3, and glucose homeostasis, are affected by CoCl2 treatment in a time‑dependent manner. In the present study, mRNA and protein levels of GLUT‑1, GLUT‑3 and HIF‑1α in astrocytes were examined by reverse transcription‑quantitative polymerase chain reaction and western blot analysis, respectively. The intracellular glucose concentration, glycogen storage, ATP content, pyruvate concentration, lactate dehydrogenase (LDH) release activity and cell viability in astrocytes were also investigated. The observations of the current study confirmed that both protein and mRNA levels of GLUT‑1 and GLUT‑3 were elevated in a time‑dependent manner induced by CoCl2 treatment, followed by accumulation of HIF‑1α. Furthermore, in the early period of CoCl2 treatment (≤8 h at 100 µM), LDH release, ATP content, glycogen storage and cell viability remained unchanged, whereas intracellular pyruvate concentration increased and glucose concentration was reduced. However, in the later period of CoCl2 treatment (>8 h at 100 µM), LDH release and intracellular pyruvate concentration increased, while intracellular glucose concentration, ATP content and glycogen storage were reduced. This may be due to disruption of homeostasis and reduced cell viability. In conclusion, alteration in the expression levels of GLUT‑1 and GLUT‑3, and the homeostasis between glucose uptake and consumption were affected by CoCl2 treatment, in a time‑dependent manner, and may result in reduced energy production and cell viability in astrocytes.
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Affiliation(s)
- Peng Wang
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Ling Li
- Department of Palliative Care and Hospice Care, The Ninth People's Hospital of Zhengzhou, Zhengzhou, Henan 450053, P.R. China
| | - Zhenxiang Zhang
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Quancheng Kan
- Department of Infectious Disease, Clinical Pharmacology Base, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Suyan Chen
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Feng Gao
- Department of Neuroimmunology, Henan Academy of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
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25
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López-Ramos JC, Duran J, Gruart A, Guinovart JJ, Delgado-García JM. Role of brain glycogen in the response to hypoxia and in susceptibility to epilepsy. Front Cell Neurosci 2015; 9:431. [PMID: 26578889 PMCID: PMC4621300 DOI: 10.3389/fncel.2015.00431] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 10/13/2015] [Indexed: 12/23/2022] Open
Abstract
Although glycogen is the only carbohydrate reserve of the brain, its overall contribution to brain functions remains unclear. It has been proposed that glycogen participates in the preservation of such functions during hypoxia. Several reports also describe a relationship between brain glycogen and susceptibility to epilepsy. To address these issues, we used our brain-specific Glycogen Synthase knockout (GYS1Nestin-KO) mouse to study the functional consequences of glycogen depletion in the brain under hypoxic conditions and susceptibility to epilepsy. GYS1Nestin-KO mice presented significantly different power spectra of hippocampal local field potentials (LFPs) than controls under hypoxic conditions. In addition, they showed greater excitability than controls for paired-pulse facilitation evoked at the hippocampal CA3–CA1 synapse during experimentally induced hypoxia, thereby suggesting a compensatory switch to presynaptic mechanisms. Furthermore, GYS1Nestin-KO mice showed greater susceptibility to hippocampal seizures and myoclonus following the administration of kainate and/or a brief train stimulation of Schaffer collaterals. We conclude that brain glycogen could play a protective role both in hypoxic situations and in the prevention of brain seizures.
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Affiliation(s)
| | - Jordi Duran
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology Barcelona, Spain ; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) Barcelona, Spain
| | - Agnès Gruart
- Division of Neurosciences, Pablo de Olavide University Seville, Spain
| | - Joan J Guinovart
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology Barcelona, Spain ; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM) Barcelona, Spain ; Department of Biochemistry and Molecular Biology, University of Barcelona Barcelona, Spain
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Hypoxia-induced neuroinflammatory white-matter injury reduced by minocycline in SHR/SP. J Cereb Blood Flow Metab 2015; 35:1145-53. [PMID: 25712499 PMCID: PMC4640265 DOI: 10.1038/jcbfm.2015.21] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 12/16/2014] [Accepted: 01/09/2015] [Indexed: 12/27/2022]
Abstract
Hypertensive small vessel disease is a major cause of vascular cognitive impairment (VCI). Spontaneously hypertensive/stroke prone rats (SHR/SP) with unilateral carotid artery occlusion (UCAO) and a Japanese permissive diet (JPD) have white-matter (WM) damage similar to that seen in VCI. We hypothesized that WM injury was due to hypoxia-mediated, blood-brain barrier (BBB) disruption. Twelve-week-old SHR/SP had UCAO/JPD and were studied with immunohistochemistry, biochemistry, multimodal magnetic resonance imaging (MRI), and Morris water maze (MWM) testing. One week after UCAO/JPD, WM showed a significant increase in hypoxia inducible factor-1α (HIF-1α), which increased further by 3 weeks. Prolyl hydroxylase-2 (PHD2) expression decreased at 1 and 3 weeks. Infiltrating T cells and neutrophils appeared around endothelial cells from 1 to 3 weeks after UCAO/JPD, and matrix metalloproteinase-9 (MMP-9) colocalized with inflammatory cells. At 3 weeks, WM immunostained for IgG, indicating BBB leakage. Minocycline (50 mg/kg intraperitoneally) was given every other day from weeks 12 to 20. Multimodal MRI showed that treatment with minocycline significantly reduced lesion size and improved cerebral blood flow. Minocycline improved performance in the MWM and prolonged survival. We propose that BBB disruption occurred secondary to hypoxia, which induced an MMP-9-mediated infiltration of leukocytes. Minocycline significantly reduced WM damage, improved behavior, and prolonged life.
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He Y, Jackman NA, Thorn TL, Vought VE, Hewett SJ. Interleukin-1β protects astrocytes against oxidant-induced injury via an NF-κB-dependent upregulation of glutathione synthesis. Glia 2015; 63:1568-80. [PMID: 25880604 DOI: 10.1002/glia.22828] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 03/12/2015] [Indexed: 01/17/2023]
Abstract
Astrocytes produce and export the antioxidant glutathione (GSH). Previously, we found that interleukin-1β (IL-1β) enhanced the expression of astrocyte system xc (-) , the transporter that delivers the rate-limiting substrate for GSH synthesis-cyst(e)ine. Herein, we demonstrate directly that IL-1β mediates a time-dependent increase in extracellular GSH levels in cortical astrocyte cultures, suggesting both enhanced synthesis and export. This increased GSH production was blocked by inhibition of nuclear factor-κB (NF-κB) activity but not by inhibition of p38 MAPK. To determine whether this increase could provide protection against oxidative stress, the oxidants tert-butyl hydroperoxide (tBOOH) and ferrous sulfate (FeSO4 ) were employed. IL-1β treatment prevented the increase in reactive oxygen species produced in astrocytes following tBOOH exposure. Additionally, the toxicity induced by tBOOH or FeSO4 exposure was significantly attenuated following treatment with IL-1β, an effect reversed by concomitant exposure to l-buthionine-S,R-sulfoximine (BSO), which prevented the IL-1β-mediated rise in GSH production. IL-1β failed to increase GSH or to provide protection against t-BOOH toxicity in astrocyte cultures derived from IL-1R1 null mutant mice. Overall, our data indicate that under certain conditions IL-1β may be an important stimulus for increasing astrocyte GSH production, and potentially, total antioxidant capacity in brain, via an NF-κB-dependent process.
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Affiliation(s)
- Yan He
- Department of Biology and Program in Neuroscience, Syracuse University, Syracuse, New York
| | - Nicole A Jackman
- Department of Neuroscience, University of Connecticut Health Center, Farmington, Connecticut
| | - Trista L Thorn
- Department of Biology and Program in Neuroscience, Syracuse University, Syracuse, New York
| | - Valarie E Vought
- Department of Biology and Program in Neuroscience, Syracuse University, Syracuse, New York
| | - Sandra J Hewett
- Department of Biology and Program in Neuroscience, Syracuse University, Syracuse, New York
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Verschoor ML, Singh G. Ets-1 regulates intracellular glutathione levels: key target for resistant ovarian cancer. Mol Cancer 2013; 12:138. [PMID: 24238102 PMCID: PMC3842663 DOI: 10.1186/1476-4598-12-138] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 11/11/2013] [Indexed: 12/19/2022] Open
Abstract
Background Ovarian cancer is characterized by high rates of metastasis and therapeutic resistance. Many chemotherapeutic agents rely on the induction of oxidative stress to cause cancer cell death, thus targeting redox regulation is a promising strategy to overcome drug resistance. Methods We have used a tetracycline-inducible Ets-1 overexpression model derived from 2008 ovarian cancer cells in the present study. To examine the role of Ets-1 in glutathione regulation we have measured intracellular reactive oxygen species and glutathione levels, as well as glutathione peroxidase enzyme activity. Glutathione synthesis was limited using transsulfuration or Sxc- pathway blocking agents, and glutamate release was measured to confirm Sxc- blockade. Cell viability following drug treatment was assessed via crystal violet assay. Oxidative stress was induced through glucose oxidase treatment, which produces hydrogen peroxide by glucose oxidation. The protein expressions of redox-related factors were measured through western blotting. Results Overexpression of Ets-1 was associated with decreased intracellular ROS, concomitantly with increased intracellular GSH, GPX antioxidant activity, and Sxc- transporter activity. Under basal conditions, inhibition of the transsulfuration pathway resulted in decreased GSH levels and GPX activity in all cell lines, whereas inhibition of Sxc- by sulfasalazine decreased GPX activity in Ets-1-expressing cells only. However, under oxidative stress the intracellular GSH levels decreased significantly in correlation with increased Ets-1 expression following sulfasalazine treatment. Conclusions In this study we have identified a role for proto-oncogene Ets-1 in the regulation of intracellular glutathione levels, and examined the effects of the anti-inflammatory drug sulfasalazine on glutathione depletion using an ovarian cancer cell model. The findings from this study show that Ets-1 mediates enhanced Sxc- activity to increase glutathione levels under oxidative stress, suggesting that Ets-1 could be a promising putative target to enhance conventional therapeutic strategies.
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Affiliation(s)
| | - Gurmit Singh
- Department of Pathology and Molecular Medicine, McMaster University, 1280 Main Street W, Hamilton, Ontario 12943, Canada.
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HIF-1α involves in neuronal apoptosis after traumatic brain injury in adult rats. J Mol Neurosci 2013; 51:1052-62. [PMID: 23979836 DOI: 10.1007/s12031-013-0084-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 07/25/2013] [Indexed: 10/26/2022]
Abstract
Hypoxia-inducible factor-1α (HIF-1α), a well-identified hypoxia-related protein, is involved in regulating the biological functions of various cell types including neurons. The traditional biological function of HIF-1α is promoting the transcription of some pro-survival genes when exposing to low oxygen conditions. Meanwhile, some studies also point out that HIF-1α shows the detrimental role in several central nervous system (CNS) disorders. Up to now, the knowledge of HIF-1α function in CNS is still limited. To investigate whether HIF-1α is involved in CNS impairment and repair, we employed a traumatic brain injury model in adult rats. Upregulation of HIF-1α was observed in the injured brain cortex by western blot analysis and immunohistochemistry staining. Terminal deoxynucleotidyl transferase deoxy-UTP nick-end labeling (TUNEL) and 4',6-diamidino-2-phenylindole (DAPI) staining suggested that HIF-1α was relevant to neuronal apoptosis after brain injury. In addition, glutamate excitotoxic model of primary cortex neurons was introduced to further investigate the role of HIF-1α in neuronal apoptosis; the result implied HIF-1α was associated with the regulation of p53 and BNIP3 in the apoptotic neurons. Based on our data, we suggested that HIF-1α might play an important role in neuronal apoptosis after traumatic brain injury in rat, which might also provide a basis for the further study on its role in regulating the transcription of target genes in apoptotic neurons, and might gain a novel strategy for the clinical therapy for traumatic brain injury.
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Corcoran A, O'Connor JJ. Hypoxia-inducible factor signalling mechanisms in the central nervous system. Acta Physiol (Oxf) 2013; 208:298-310. [PMID: 23692777 DOI: 10.1111/apha.12117] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 04/01/2013] [Accepted: 05/16/2013] [Indexed: 12/22/2022]
Abstract
In the CNS, neurones are highly sensitive to the availability of oxygen. In conditions where oxygen availability is decreased, neuronal function can be altered, leading to injury and cell death. Hypoxia has been implicated in a number of central nervous system pathologies including stroke, head trauma and neurodegenerative diseases. Cellular responses to oxygen deprivation are complex and result in activation of short- and long-term mechanisms to conserve energy and protect cells. Failure of synaptic transmission can be observed within minutes following this hypoxia. The acute effects of hypoxia on synaptic transmission are primarily mediated by altering ion fluxes across membranes, pre-synaptic effects of adenosine and other actions at glutamatergic receptors. A more long-term feature of the response of neurones to hypoxia is the activation of transcription factors such as hypoxia-inducible factor. The activation of hypoxia-inducible factor is governed by a family of dioxygenases called hypoxia-inducible factor prolyl 4 hydroxylases (PHDs). Under hypoxic conditions, PHD activity is inhibited, thereby allowing hypoxia-inducible factor to accumulate and translocate to the nucleus, where it binds to the hypoxia-responsive element sequences of target gene promoters. Inhibition of PHD activity stabilizes hypoxia-inducible factor and other proteins thus acting as a neuroprotective agent. This review will focus on the response of neuronal cells to hypoxia-inducible factor and its targets, including the prolyl hydroxylases. We also present evidence for acute effects of PHD inhibition on synaptic transmission and plasticity in the hippocampus.
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Affiliation(s)
- A. Corcoran
- UCD School of Biomolecular and Biomedical Science; UCD Conway Institute of Biomolecular and Biomedical Research; UniversityCollege Dublin; Dublin; Ireland
| | - J. J. O'Connor
- UCD School of Biomolecular and Biomedical Science; UCD Conway Institute of Biomolecular and Biomedical Research; UniversityCollege Dublin; Dublin; Ireland
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31
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Reactive Astrocytes, Astrocyte Intermediate Filament Proteins, and Their Role in the Disease Pathogenesis. THE CYTOSKELETON 2013. [DOI: 10.1007/978-1-62703-266-7_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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