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Turlova E, Ji D, Deurloo M, Wong R, Fleig A, Horgen FD, Sun HS, Feng ZP. Hypoxia-Induced Neurite Outgrowth Involves Regulation Through TRPM7. Mol Neurobiol 2023; 60:836-850. [PMID: 36378470 DOI: 10.1007/s12035-022-03114-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 10/26/2022] [Indexed: 11/16/2022]
Abstract
Transient receptor potential melastatin 7 (TRPM7) is a ubiquitously expressed divalent cation channel that plays a key role in cell functions such as ion homeostasis, cell proliferation, survival, and cytoskeletal dynamics and mediates cells death in hypoxic and ischemic conditions. Previously, TRPM7 was found to play a role in the neurite outgrowth and maturation of primary hippocampal neurons. Either knockdown of TRPM7 with target-specific shRNA or blocking channel conductance by a specific blocker waixenicin A enhanced axonal outgrowth in the primary neuronal culture. In this study, we investigated whether and how TPRM7 is involved in hypoxia-altered neurite outgrowth patterns in E16 hippocampal neuron cultures. We demonstrate that short-term hypoxia activated the MEK/ERK and PI3K/Akt pathways, reduced TRPM7 activity, and enhanced axonal outgrowth of neuronal cultures. On the other hand, long-term hypoxia caused a progressive retraction of axons and dendrites that could be attenuated by the TRPM7-specific inhibitor waixenicin A. Further, we demonstrate that in the presence of astrocytes, axonal retraction in long-term hypoxic conditions was enhanced, and TRPM7 block by waixenicin A prevented this retraction. Our data demonstrate the effect of hypoxia on TRPM7 activity and axonal outgrowth/retraction in cultures with or without astrocytes present.
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Affiliation(s)
- Ekaterina Turlova
- Department of Surgery, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Ontario, M5S 1A8, Toronto, Canada
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Delphine Ji
- Department of Surgery, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Ontario, M5S 1A8, Toronto, Canada
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Marielle Deurloo
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Raymond Wong
- Department of Surgery, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Ontario, M5S 1A8, Toronto, Canada
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Andrea Fleig
- Center for Biomedical Research at The Queen's Medical Center and John A. Burns School of Medicine and Cancer Center at the, University of Hawaii, Honolulu, HI, 96720, USA
| | - F David Horgen
- Department of Natural Sciences, Hawaii Pacific University, Kaneohe, HI, 96744, USA
| | - Hong-Shuo Sun
- Department of Surgery, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Ontario, M5S 1A8, Toronto, Canada.
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada.
- Department of Pharmacology, Temerty Faculty of Medicine, University of Toronto, King's College Circle, Toronto, Ontario, M5S 1A8, Canada.
- Leslie Dan Faculty of Pharmacy, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada.
| | - Zhong-Ping Feng
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada.
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Seawater Immersion Aggravates Early Mitochondrial Dysfunction and Increases Neuronal Apoptosis After Traumatic Brain Injury. Cell Mol Neurobiol 2019; 40:447-457. [PMID: 31667702 DOI: 10.1007/s10571-019-00747-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 10/17/2019] [Indexed: 10/25/2022]
Abstract
Traumatic brain injury (TBI) is a major cause of death and disability in naval warfare. Due to the unique physiochemical properties of seawater, immersion in it exacerbates TBI and induces severe neural damage and complications. However, the characteristics and underlying mechanisms of seawater-immersed TBI remain unclear. Mitochondrial dysfunction is a major cause of TBI-associated brain damage because it leads to oxidative stress, decrease in energy production, and apoptosis. Thus, the present study aimed to further elucidate the current understanding of the pathology of seawater-immersed TBI, particularly the role of mitochondrial dysfunction, using a well-defined rat model of fluid percussion injury and a stretch injury model comprising cultured neurons. The biochemical and pathological markers of brain-related and neuronal injuries were evaluated. Histological analysis suggested that seawater immersion enhanced brain tissue injury and induced a significant increase in apoptosis in rats with TBI. Additionally, lactate dehydrogenase release occurred earlier and at higher levels in stretched neurons at 24 h after seawater immersion, which was consistent with more severe morphological changes and enhanced apoptosis. Furthermore, seawater immersion induced more rapid decreases in mitochondrial membrane potential, adenosine triphosphate (ATP) content, and H+-ATPase activity in the cortices of TBI rats. In addition, the immunochemical results revealed that seawater immersion further attenuated mitochondrial function in neurons exposed to stretch injury. The increases in neuronal damage and apoptosis triggered by seawater immersion were positively correlated with mitochondrial dysfunction in both in vivo and in vitro models. Thus, the present findings strengthen the current understanding of seawater-immersed TBI. Moreover, because seawater immersion aggravates mitochondrial dysfunction and contributes to post-traumatic neuronal cell death, it is important to consider mitochondria as a therapeutic target for seawater-immersed TBI.
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Jiang JX, Aitken KJ, Sotiropolous C, Kirwan T, Panchal T, Zhang N, Pu S, Wodak S, Tolg C, Bägli DJ. Phenotypic switching induced by damaged matrix is associated with DNA methyltransferase 3A (DNMT3A) activity and nuclear localization in smooth muscle cells (SMC). PLoS One 2013; 8:e69089. [PMID: 24282625 PMCID: PMC3735580 DOI: 10.1371/journal.pone.0069089] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Accepted: 06/09/2013] [Indexed: 12/27/2022] Open
Abstract
Extracellular matrix changes are often crucial inciting events for fibroproliferative disease. Epigenetic changes, specifically DNA methylation, are critical factors underlying differentiated phenotypes. We examined the dependency of matrix-induced fibroproliferation and SMC phenotype on DNA methyltransferases. The cooperativity of matrix with growth factors, cell density and hypoxia was also examined. Primary rat visceral SMC of early passage (0–2) were plated on native collagen or damaged/heat-denatured collagen. Hypoxia was induced with 3% O2 (balanced 5% CO2 and 95% N2) over 48 hours. Inhibitors were applied 2–3 hours after cells were plated on matrix, or immediately before hypoxia. Cells were fixed and stained for DNMT3A and smooth muscle actin (SMA) or smooth muscle myosin heavy chain. Illumina 450 K array of CpG sites was performed on bisulfite-converted DNA from smooth muscle cells on damaged matrix vs native collagen. Matrix exquisitely regulates DNMT3A localization and expression, and influences differentiation in SMCs exposed to denatured matrix +/− hypoxia. Analysis of DNA methylation signatures showed that Matrix caused significant DNA methylation alterations in a discrete number of CpG sites proximal to genes related to SMC differentiation. Matrix has a profound effect on the regulation of SMC phenotype, which is associated with altered expression, localization of DNMTs and discrete changes DNA methylation.
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Affiliation(s)
- Jia-Xin Jiang
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Urology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Karen J. Aitken
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Urology, Hospital for Sick Children, Toronto, Ontario, Canada
- * E-mail:
| | - Chris Sotiropolous
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Urology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Tyler Kirwan
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Urology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Trupti Panchal
- Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Nicole Zhang
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Shuye Pu
- Centre for Computational Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Shoshana Wodak
- Centre for Computational Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Cornelia Tolg
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Urology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Darius J. Bägli
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Urology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Sciences, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
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Gladman SJ, Ward RE, Michael-Titus AT, Knight MM, Priestley JV. The effect of mechanical strain or hypoxia on cell death in subpopulations of rat dorsal root ganglion neurons in vitro. Neuroscience 2010; 171:577-87. [PMID: 20674687 DOI: 10.1016/j.neuroscience.2010.07.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 07/01/2010] [Accepted: 07/04/2010] [Indexed: 12/22/2022]
Abstract
Spinal nerves and their associated dorsal root ganglion (DRG) cells can be subject to mechanical deformation and hypoxia associated with pathology such as disc herniation, spinal stenosis and spine trauma. There is very limited information on the response of adult DRG neurons to such stressors. In this study we used an in vitro approach to examine the response of adult DRG cells to (a) mechanical, hypoxic, and combined injuries; and (b) to compare the effects on injury on nociceptive and non-nociceptive neurons, as well as on non-neuronal cells. Mechanical injury (20% tensile strain) led to significant neuronal cell death (assessed by ethidium homodimer-1 labelling), which was proportional to strain duration (5 min, 1 h, 6 h or 18 h). Hypoxia (2% O(2) for 24 h) also promoted death of DRG neurons, and was further enhanced when mechanical strain and hypoxia were combined. Both mechanical strain and hypoxia significantly decreased the maximum neurite length. Conversely, death of non-neuronal cells was only increased by hypoxia and not by mechanical strain. Total cell death in response to mechanical injury or hypoxia was similar in both non-nociceptive (neurofilament, NF-200 immunoreactive) and nociceptive (calcitonin gene-related peptide, CGRP immunoreactive) neurons, but apoptosis (assessed by activated caspase-3 immunostaining) was significantly higher in CGRP than NF-200 neurons. Surprisingly, cell death of non-peptidergic nociceptors (identified by Griffonia simplicifolia IB4 lectin binding) was already high in control cultures, and was not increased further by either mechanical stretch or hypoxia. These results provide detailed information on the response of adult DRG subpopulations to hypoxia and mechanical strain, and describe in vitro models that could be useful for screening potential neuroprotective agents.
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Affiliation(s)
- S J Gladman
- Centre for Neuroscience and Trauma, Blizard Institute of Cell and Molecular Science, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK.
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Chen YC, Smith DH, Meaney DF. In-vitro approaches for studying blast-induced traumatic brain injury. J Neurotrauma 2009; 26:861-76. [PMID: 19397424 DOI: 10.1089/neu.2008.0645] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Traumatic brain injury caused by explosive or blast events is currently divided into four phases: primary, secondary, tertiary, and quaternary blast injury. These phases of blast-induced traumatic brain injury (bTBI) are biomechanically distinct, and can be modeled in both in-vivo and in-vitro systems. The purpose of this review is to consider the mechanical phases of bTBI, how these phases are reproduced with in-vitro models, and to review findings from these models to assess how each phase of bTBI can be examined in more detail. Highlighted are some important gaps in the literature that may be addressed in the future to better identify the exact contributing mechanisms for bTBI. These in-vitro models, viewed in combination with in-vivo models and clinical studies, can be used to assess both the mechanisms and possible treatments for this type of trauma.
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Affiliation(s)
- Yung Chia Chen
- Departments of Bioengineering, University of Pennsylvania, 210 S. 33rd Street, Philadelphia, PA 19104, USA
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Margulies S, Hicks R. Combination therapies for traumatic brain injury: prospective considerations. J Neurotrauma 2009; 26:925-39. [PMID: 19331514 PMCID: PMC2857809 DOI: 10.1089/neu.2008.0794] [Citation(s) in RCA: 189] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Traumatic brain injury (TBI) initiates a cascade of numerous pathophysiological events that evolve over time.Despite the complexity of TBI, research aimed at therapy development has almost exclusively focused on single therapies, all of which have failed in multicenter clinical trials. Therefore, in February 2008 the National Institute of Neurological Disorders and Stroke, with support from the National Institute of Child Health and Development, the National Heart, Lung, and Blood Institute, and the Department of Veterans Affairs, convened a workshop to discuss the opportunities and challenges of testing combination therapies for TBI. Workshop participants included clinicians and scientists from a variety of disciplines, institutions, and agencies. The objectives of the workshop were to: (1) identify the most promising combinations of therapies for TBI; (2) identify challenges of testing combination therapies in clinical and pre-clinical studies; and (3) propose research methodologies and study designs to overcome these challenges. Several promising combination therapies were discussed, but no one combination was identified as being the most promising. Rather, the general recommendation was to combine agents with complementary targets and effects (e.g., mechanisms and time-points), rather than focusing on a single target with multiple agents. In addition, it was recommended that clinical management guidelines be carefully considered when designing pre-clinical studies for therapeutic development.To overcome the challenges of testing combination therapies it was recommended that statisticians and the U.S. Food and Drug Administration be included in early discussions of experimental design. Furthermore, it was agreed that an efficient and validated screening platform for candidate therapeutics, sensitive and clinically relevant biomarkers and outcome measures, and standardization and data sharing across centers would greatly facilitate the development of successful combination therapies for TBI. Overall there was great enthusiasm for working collaboratively to act on these recommendations.
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Affiliation(s)
- Susan Margulies
- School of Engineering and Applied Science, Department of Bioengineering, University of Pennsylvania, 210 S. 33rd Street, Philadelphia, PA 19104-6321, USA.
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Woronowicz A, Amith SR, Davis VW, Jayanth P, De Vusser K, Laroy W, Contreras R, Meakin SO, Szewczuk MR. Trypanosome trans-sialidase mediates neuroprotection against oxidative stress, serum/glucose deprivation, and hypoxia-induced neurite retraction in Trk-expressing PC12 cells. Glycobiology 2007; 17:725-34. [PMID: 17389653 DOI: 10.1093/glycob/cwm034] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Trypanosome trans-sialidase (TS) is a sialic acid-transferring enzyme and a novel ligand of tyrosine kinase (TrkA) receptors but not of neurotrophin receptor p75NTR. Here, we show that TS targets TrkB receptors on TrkB-expressing pheochromocytoma PC12 cells and colocalizes with TrkB receptor internalization and phosphorylation (pTrkB). Wild-type TS but not the catalytically inactive mutant TSDeltaAsp98-Glu induces pTrkB and mediates cell survival responses against death caused by oxidative stress in TrkA- and TrkB-expressing cells like those seen with nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). These same effects are not observed in Trk deficient PC12(nnr5) cells, but are re-established in PC12(nnr5) cells stably transfected with TrkA or TrkB, are partially blocked by inhibitors of tyrosine kinase (K-252a), mitogen-activated protein/mitogen-activated kinase (PD98059) and completely blocked by LY294002, an inhibitor of phosphatidylinositol 3-kinase (PI3K). Both TrkA- and TrkB-expressing cells pretreated with TS or their natural ligands are protected against cell death caused by serum/glucose deprivation or from hypoxia-induced neurite retraction. The cell survival effects of NGF and BDNF against oxidative stress are significantly inhibited by the neuraminidase inhibitor, Tamiflu. Together, these observations suggest that trypanosome TS mimics neurotrophic factors in cell survival responses against oxidative stress, hypoxia-induced neurite retraction and serum/glucose deprivation.
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Affiliation(s)
- Alicja Woronowicz
- Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada K7L3N6
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Engel DC, Slemmer JE, Vlug AS, Maas AIR, Weber JT. Combined effects of mechanical and ischemic injury to cortical cells: secondary ischemia increases damage and decreases effects of neuroprotective agents. Neuropharmacology 2005; 49:985-95. [PMID: 16046227 DOI: 10.1016/j.neuropharm.2005.05.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2005] [Revised: 04/20/2005] [Accepted: 05/05/2005] [Indexed: 11/25/2022]
Abstract
Traumatic brain injury (TBI) involves direct mechanical damage, which may be aggravated by secondary insults such as ischemia. We utilized an in vitro model of stretch-induced injury to investigate the effects of mechanical and combined mechanical/ischemic insults to cultured mouse cortical cells. Stretch injury alone caused significant neuronal loss and increased uptake of the dye, propidium iodide, suggesting cellular membrane damage to both glia and neurons. Exposure of cultures to ischemic conditions for 24h, or a combination of stretch and 24h of ischemia, caused greater neuronal loss compared to stretch injury alone. Next, we tested the neuroprotective effects of superoxide dismutase (SOD), and the nitric oxide (NO) synthase inhibitors 7-nitroindazole (7-NINA) and lubeluzole. In general, these agents decreased neuronal loss following stretch injury alone, but were relatively ineffective against the combined injury paradigm. A combination of SOD with 7-NINA or lubeluzole offered no additional protection than single drug treatment against stretch alone or combined injury. These results suggest that the effects of primary mechanical damage and secondary ischemia to cortical neurons are cumulative, and drugs that scavenge superoxide or reduce NO production may not be effective for treating the secondary ischemia that often accompanies TBI.
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Affiliation(s)
- Doortje C Engel
- Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands
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