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Ridlen R, McGrath K, Gorrie CA. Animal models of compression spinal cord injury. J Neurosci Res 2022; 100:2201-2212. [PMID: 36121155 PMCID: PMC9825893 DOI: 10.1002/jnr.25120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 01/11/2023]
Abstract
Compression spinal cord injuries are a common cause of morbidity in people who experience a spinal cord injury (SCI). Either as a by-product of a traumatic injury or due to nontraumatic conditions such as cervical myelitis, compression injuries are growing in prevalence clinically and many attempts of animal replication have been described within the literature. These models, however, often focus on the traumatic side of injury or mimic short-term injuries that are not representative of the majority of compression SCI. Of this, nontraumatic spinal cord injuries are severely understudied and have an increased prevalence in elderly populations, adults, and children. Therefore, there is a need to critically evaluate the current animal models of compression SCI and their suitability as a method for clinically relevant data that can help reduce morbidity and mortality of SCI. In this review, we reviewed the established and emerging methods of animal models of compression SCI. These models are the clip, balloon, solid spacer, expanding polymer, remote, weight drop, calibrated forceps, screw, and strap methods. These methods showed that there is a large reliance on the use of laminectomy to induce injury. Furthermore, the age range of many studies does not reflect the elderly and young populations that commonly suffer from compression injuries. It is therefore important to have techniques and methods that are able to minimize secondary effects of the surgeries, and are representative of the clinical cases seen so that treatments and interventions can be developed that are specific.
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Affiliation(s)
- Reggie Ridlen
- School of Life SciencesUniversity of Technology SydneyUltimoNew South WalesAustralia
| | - Kristine McGrath
- School of Life SciencesUniversity of Technology SydneyUltimoNew South WalesAustralia
| | - Catherine A. Gorrie
- School of Life SciencesUniversity of Technology SydneyUltimoNew South WalesAustralia
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2
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Monti E, Mancini A, Marras E, Gariboldi MB. Targeting Mitochondrial ROS Production to Reverse the Epithelial-Mesenchymal Transition in Breast Cancer Cells. Curr Issues Mol Biol 2022; 44:5277-5293. [PMID: 36354671 PMCID: PMC9689492 DOI: 10.3390/cimb44110359] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 10/21/2022] [Accepted: 10/26/2022] [Indexed: 03/03/2024] Open
Abstract
Experimental evidence implicates reactive oxygen species (ROS) generation in the hypoxic stabilization of hypoxia-inducible factor (HIF)-1α and in the subsequent expression of promoters of tumor invasiveness and metastatic spread. However, the role played by mitochondrial ROS in hypoxia-induced Epithelial-Mesenchymal Transition (EMT) activation is still unclear. This study was aimed at testing the hypothesis that the inhibition of hypoxia-induced mitochondrial ROS production, mainly at the mitochondrial Complex III UQCRB site, could result in the reversion of EMT, in addition to decreased HIF-1α stabilization. The role of hypoxia-induced ROS increase in HIF-1α stabilization and the ability of antioxidants, some of which directly targeting mitochondrial Complex III, to block ROS production and HIF-1α stabilization and prevent changes in EMT markers were assessed by evaluating ROS, HIF-1α and EMT markers on breast cancer cells, following 48 h treatment with the antioxidants. The specific role of UQCRB in hypoxia-induced EMT was also evaluated by silencing its expression through RNA interference and by assessing the effects of its downregulation on ROS production, HIF-1α levels, and EMT markers. Our results confirm the pivotal role of UQCRB in hypoxic signaling inducing EMT. Thus, UQCRB might be a new therapeutic target for the development of drugs able to reverse EMT by blocking mitochondrial ROS production.
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Affiliation(s)
- Elena Monti
- Department of Biotechnology and Life Sciences (DBSV), University of Insubria, Via J.H. Dunant 3, 21100 Varese, Italy
| | - Alessandro Mancini
- Department of Translational Medical Sciences, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy
- BioUp Sagl, 6900 Lugano, Switzerland
| | - Emanuela Marras
- Department of Biotechnology and Life Sciences (DBSV), University of Insubria, Via J.H. Dunant 3, 21100 Varese, Italy
| | - Marzia Bruna Gariboldi
- Department of Biotechnology and Life Sciences (DBSV), University of Insubria, Via J.H. Dunant 3, 21100 Varese, Italy
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3
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Sarkar A, Kim KT, Tsymbalyuk O, Keledjian K, Wilhelmy BE, Sherani NA, Jia X, Gerzanich V, Simard JM. A Direct Comparison of Physical Versus Dihydrocapsaicin-Induced Hypothermia in a Rat Model of Traumatic Spinal Cord Injury. Ther Hypothermia Temp Manag 2022; 12:90-102. [PMID: 35675523 PMCID: PMC9231662 DOI: 10.1089/ther.2021.0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Spinal cord injury (SCI) is a devastating neurological condition with no effective treatment. Hypothermia induced by physical means (cold fluid) is established as an effective therapy in animal models of SCI, but its clinical translation to humans is hampered by several constraints. Hypothermia induced pharmacologically may be noninferior or superior to physically induced hypothermia for rapid, convenient systemic temperature reduction, but it has not been investigated previously in animal models of SCI. We used a rat model of SCI to compare outcomes in three groups: (1) normothermic controls; (2) hypothermia induced by conventional physical means; (3) hypothermia induced by intravenous (IV) dihydrocapsaicin (DHC). Male rats underwent unilateral lower cervical SCI and were treated after a 4-hour delay with physical cooling or IV DHC (∼0.60 mg/kg total) cooling (both 33.0 ± 1.0°C) lasting 4 hours; controls were kept normothermic. Telemetry was used to monitor temperature and heart rate during and after treatments. In two separate experiments, one ending at 48 hours, the other at 6 weeks, “blinded” investigators evaluated rats in the three groups for neurological function followed by histopathological evaluation of spinal cord tissues. DHC reliably induced systemic cooling to 32–33°C. At both the time points examined, the two modes of hypothermia yielded similar improvements in neurological function and lesion size compared with normothermic controls. Our results indicate that DHC-induced hypothermia may be comparable with physical hypothermia in efficacy, but more clinically feasible to administer than physical hypothermia.
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Affiliation(s)
- Amrita Sarkar
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kevin T Kim
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Orest Tsymbalyuk
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kaspar Keledjian
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Bradley E Wilhelmy
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Nageen A Sherani
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - J Marc Simard
- Department of Neurosurgery, Pathology and Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Lan H, Wu L, Sun R, Keller NP, Yang K, Ye L, He S, Zhang F, Wang S. The HosA Histone Deacetylase Regulates Aflatoxin Biosynthesis Through Direct Regulation of Aflatoxin Cluster Genes. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:1210-1228. [PMID: 30986121 DOI: 10.1094/mpmi-01-19-0033-r] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Histone deacetylases (HDACs) always function as corepressors and sometimes as coactivators in the regulation of fungal development and secondary metabolite production. However, the mechanism through which HDACs play positive roles in secondary metabolite production is still unknown. Here, classical HDAC enzymes were identified and analyzed in Aspergillus flavus, a fungus that produces one of the most carcinogenic secondary metabolites, aflatoxin B1 (AFB1). Characterization of the HDACs revealed that a class I family HDAC, HosA, played crucial roles in growth, reproduction, the oxidative stress response, AFB1 biosynthesis, and pathogenicity. To a lesser extent, a class II family HDAC, HdaA, was also involved in sclerotia formation and AFB1 biosynthesis. An in vitro analysis of HosA revealed that its HDAC activity was considerably diminished at nanomolar concentrations of trichostatin A. Notably, chromatin immunoprecipitation experiments indicated that HosA bound directly to AFB1 biosynthesis cluster genes to regulate their expression. Finally, we found that a transcriptional regulator, SinA, interacts with HosA to regulate fungal development and AFB1 biosynthesis. Overall, our results reveal a novel mechanism by which classical HDACs mediate the induction of secondary metabolite genes in fungi.
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Affiliation(s)
- Huahui Lan
- Fujian Key Laboratory of Pathogenic Fungi Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Lianghuan Wu
- Fujian Key Laboratory of Pathogenic Fungi Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ruilin Sun
- Fujian Key Laboratory of Pathogenic Fungi Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Nancy P Keller
- Departments of Bacteriology, Medical Microbiology, and Immunology, University of Wisconsin-Madison, Madison, WI, U.S.A
| | - Kunlong Yang
- Fujian Key Laboratory of Pathogenic Fungi Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Liuqing Ye
- Fujian Key Laboratory of Pathogenic Fungi Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shuibin He
- Fujian Key Laboratory of Pathogenic Fungi Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Feng Zhang
- Fujian Key Laboratory of Pathogenic Fungi Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shihua Wang
- Fujian Key Laboratory of Pathogenic Fungi Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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Abstract
Spinal cord injury (SCI) is a major health problem and is associated with a diversity of neurological symptoms. Pathophysiologically, dysfunction after SCI results from the culmination of tissue damage produced both by the primary insult and a range of secondary injury mechanisms. The application of hypothermia has been demonstrated to be neuroprotective after SCI in both experimental and human studies. The myriad of protective mechanisms of hypothermia include the slowing down of metabolism, decreasing free radical generation, inhibiting excitotoxicity and apoptosis, ameliorating inflammation, preserving the blood spinal cord barrier, inhibiting astrogliosis, promoting angiogenesis, as well as decreasing axonal damage and encouraging neurogenesis. Hypothermia has also been combined with other interventions, such as antioxidants, anesthetics, alkalinization and cell transplantation for additional benefit. Although a large body of work has reported on the effectiveness of hypothermia as a neuroprotective approach after SCI and its application has been translated to the clinic, a number of questions still remain regarding its use, including the identification of hypothermia's therapeutic window, optimal duration and the most appropriate rewarming rate. In addition, it is necessary to investigate the neuroprotective effect of combining therapeutic hypothermia with other treatment strategies for putative synergies, particularly those involving neurorepair.
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Affiliation(s)
- Jiaqiong Wang
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, the Lois Pope Life Center, Locator code (R-48), PO BOX 016960, Miami, FL 33136, USA.
| | - Damien D Pearse
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, the Lois Pope Life Center, Locator code (R-48), PO BOX 016960, Miami, FL 33136, USA.
- The Department of Neurological Surgery, University of Miami Miller School of Medicine, the Lois Pope Life Center, Locator code (R-48), PO BOX 016960, Miami, FL 33136, USA.
- The Neuroscience Program, University of Miami Miller School of Medicine, the Lois Pope Life Center, Locator code (R-48), PO BOX 016960, Miami, FL 33136, USA.
- The Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, the Lois Pope Life Center, Locator code (R-48), PO BOX 016960, Miami, FL 33136, USA.
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Mazensky D, Danko J, Petrovova E, Supuka P, Supukova A. Anatomical study of the arterial blood supply to the thoracolumbar spinal cord in guinea pig. Anat Sci Int 2014; 90:203-8. [PMID: 24966109 DOI: 10.1007/s12565-014-0245-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 06/13/2014] [Indexed: 11/29/2022]
Abstract
Guinea pigs are frequently used as experimental models in studies of ischemic spinal cord injury. The aim of this study was to describe the arterial blood supply to the thoracolumbar spinal cord in 20 adult English self guinea pigs using the corrosion and dissection techniques. The dorsal intercostal arteries arising from the dorsal surface of the thoracic aorta were found as follows: in eight pairs in 70% of cases, in seven pairs in 20% of cases and in nine pairs in 10% of cases. Paired lumbar arteries were present as seven pairs in all the cases. The occurrence of the ventral and dorsal branches of the spinal rami observed in the thoracic and lumbar region was higher on the left than on the right. The artery of Adamkiewicz was present in 60% of cases as a single vessel and in 40% of cases as a double vessel. On the dorsal surface of the spinal cord, we found two dorsal spinal arteries in 60% of cases and three in 40% of cases. The presence of the artery of Adamkiewicz and nearly regular segmental blood supplying the thoracolumbar part of the spinal cord in all our studied animals is the reason for using guinea pigs as a simple model of ischemic damage to the thoracolumbar part of the spinal cord.
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Affiliation(s)
- David Mazensky
- Department of Anatomy, Histology and Physiology, University of Veterinary Medicine and Pharmacy in Kosice, Komenskeho 73, 041 81, Kosice, Slovak Republic,
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The Neuroprotective Ability of Polyethylene Glycol is Affected by Temperature in Ex Vivo Spinal Cord Injury Model. J Membr Biol 2013; 246:613-9. [DOI: 10.1007/s00232-013-9574-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 06/04/2013] [Indexed: 11/26/2022]
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Chen B, Bohnert D, Borgens RB, Cho Y. Pushing the science forward: chitosan nanoparticles and functional repair of CNS tissue after spinal cord injury. J Biol Eng 2013; 7:15. [PMID: 23731718 PMCID: PMC3684525 DOI: 10.1186/1754-1611-7-15] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 05/21/2013] [Indexed: 03/01/2023] Open
Abstract
BACKGROUND We continue our exploration of the large polysaccharide polymer Chitosan as an acute therapy for severe damage to the nervous system. We tested the action of subcutaneously injected nanoparticles (~ 100 - 200 nanometers in diameter; 1 mg per ml) against control injections (silica particle of the same size and concentration) in a standardized in vivo spinal cord injury model. These functional tests used standardized physiological measurements of evoked potentials arriving at the sensorimotor cortex subsequent to stimulation of the tibial nerve of the contralateral hindlimb. We further explored the degree of acetylation and molecular weight of chitosan on the success of sealing cell damage using specific probes of membrane integrity. RESULTS Not one of the control group showed restored conduction of evoked potentials stimulated from the tibial nerve of the hindleg - through the lesion - and recorded at the sensorimotor cortex of the brain. Investigation if the degree of acetylation and molecular weight impacted "membrane sealing" properties of Chitosan were unsuccessful. Dye - exchange membrane probes failed to show a difference between the comparators in the function of Chitosan in ex vivo injured spinal cord tests. CONCLUSIONS We found that Chitosan nanoparticles effectively restore nerve impulse transmission through the crushed adult guinea pig spinal cord in vivo after severe crush/compression injury. The tests of the molecular weight (MW) and degree of acetylation did not produce any improvement in Chitosan's membrane sealing properties.
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Affiliation(s)
- Bojun Chen
- Center for Paralysis Research, Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West, Lafayette, IN 47907, USA
| | - Debra Bohnert
- Center for Paralysis Research, Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West, Lafayette, IN 47907, USA
| | - Richard Ben Borgens
- Center for Paralysis Research, Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West, Lafayette, IN 47907, USA
- Weldon School of Biomedical Engineering, Purdue University, West, Lafayette, IN 47907, USA
| | - Youngnam Cho
- Center for Paralysis Research, Department of Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West, Lafayette, IN 47907, USA
- Present address: New Experimental Therapeutics Branch, National Cancer Center, 809 Madu-1dong, Ilsandong-gu, Goyang-si, Gyeonggi-do, 410-769, Korea
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Sun W, Fu Y, Shi Y, Cheng JX, Cao P, Shi R. Paranodal myelin damage after acute stretch in Guinea pig spinal cord. J Neurotrauma 2011; 29:611-9. [PMID: 21988176 DOI: 10.1089/neu.2011.2086] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mechanical injury causes myelin disruption and subsequent axonal conduction failure in the mammalian spinal cord. However, the underlying mechanism is not well understood. In mammalian myelinated axons, proper paranodal myelin structure is crucial for the generation and propagation of action potentials. The exposure of potassium channels at the juxtaparanodal region due to myelin disruption is thought to induce outward potassium currents and inhibit the genesis of the action potential, leading to conduction failure. Using multimodal imaging techniques, we provided anatomical evidence demonstrating paranodal myelin disruption and consequent exposure and redistribution of potassium channels following mechanical insult in the guinea pig spinal cord. Decompaction of paranodal myelin was also observed. It was shown that paranodal demyelination can result from both an initial physical impact and secondary biochemical reactions that are calcium dependent. 4-Aminopyridine (4-AP), a known potassium channel blocker, can partially restore axonal conduction, which further implicates the role of potassium channels in conduction failure. We provide important evidence of paranodal myelin damage, the role of potassium channels in conduction loss, and the therapeutic value of potassium blockade as an effective intervention to restore function following spinal cord trauma.
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Affiliation(s)
- Wenjing Sun
- Department of Basic Medical Sciences, Center for Paralysis Research, Purdue University, West Lafayette, Indiana, USA
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10
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Zielonka J, Kalyanaraman B. Hydroethidine- and MitoSOX-derived red fluorescence is not a reliable indicator of intracellular superoxide formation: another inconvenient truth. Free Radic Biol Med 2010; 48:983-1001. [PMID: 20116425 PMCID: PMC3587154 DOI: 10.1016/j.freeradbiomed.2010.01.028] [Citation(s) in RCA: 383] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Revised: 01/20/2010] [Accepted: 01/21/2010] [Indexed: 12/15/2022]
Abstract
Hydroethidine (HE; or dihydroethidium) is the most popular fluorogenic probe used for detecting intracellular superoxide radical anion. The reaction between superoxide and HE generates a highly specific red fluorescent product, 2-hydroxyethidium (2-OH-E(+)). In biological systems, another red fluorescent product, ethidium, is also formed, usually at a much higher concentration than 2-OH-E(+). In this article, we review the methods to selectively detect the superoxide-specific product (2-OH-E(+)) and the factors affecting its levels in cellular and biological systems. The most important conclusion of this review is that it is nearly impossible to assess the intracellular levels of the superoxide-specific product, 2-OH-E(+), using confocal microscopy or other fluorescence-based microscopic assays and that it is essential to measure by HPLC the intracellular HE and other oxidation products of HE, in addition to 2-OH-E(+), to fully understand the origin of red fluorescence. The chemical reactivity of mitochondria-targeted hydroethidine (Mito-HE, MitoSOX red) with superoxide is similar to the reactivity of HE with superoxide, and therefore, all of the limitations attributed to the HE assay are applicable to Mito-HE (or MitoSOX) as well.
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Affiliation(s)
- Jacek Zielonka
- Department of Biophysics and Free Radical Research Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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Glutamate excitotoxicity inflicts paranodal myelin splitting and retraction. PLoS One 2009; 4:e6705. [PMID: 19693274 PMCID: PMC2725320 DOI: 10.1371/journal.pone.0006705] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Accepted: 07/20/2009] [Indexed: 11/19/2022] Open
Abstract
Paranodal myelin damage is observed in white matter injury. However the culprit for such damage remains unknown. By coherent anti-Stokes Raman scattering imaging of myelin sheath in fresh tissues with sub-micron resolution, we observed significant paranodal myelin splitting and retraction following glutamate application both ex vivo and in vivo. Multimodal multiphoton imaging further showed that glutamate application broke axo-glial junctions and exposed juxtaparanodal K+ channels, resulting in axonal conduction deficit that was demonstrated by compound action potential measurements. The use of 4-aminopyridine, a broad-spectrum K+ channel blocker, effectively recovered both the amplitude and width of compound action potentials. Using CARS imaging as a quantitative readout of nodal length to diameter ratio, the same kind of paranodal myelin retraction was observed with applications of Ca2+ ionophore A23187. Moreover, exclusion of Ca2+ from the medium or application of calpain inhibitor abolished paranodal myelin retraction during glutamate exposure. Examinations of glutamate receptor agonists and antagonists further showed that the paranodal myelin damage was mediated by NMDA and kainate receptors. These results suggest that an increased level of glutamate in diseased white matter could impair paranodal myelin through receptor-mediated Ca2+ overloading and subsequent calpain activation.
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Munnamalai V, Suter DM. Reactive oxygen species regulate F-actin dynamics in neuronal growth cones and neurite outgrowth. J Neurochem 2008; 108:644-61. [PMID: 19054285 DOI: 10.1111/j.1471-4159.2008.05787.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Reactive oxygen species are well known for their damaging effects due to oxidation of lipids, proteins and DNA that ultimately result in cell death. Accumulating evidence indicates that reactive oxygen species also have important signaling functions in cell proliferation, differentiation, cell motility and apoptosis. Here, we tested the hypothesis whether reactive oxygen species play a physiological role in regulating F-actin structure and dynamics in neuronal growth cones. Lowering cytoplasmic levels of reactive oxygen species with a free radical scavenger, N-tert-butyl-alpha-phenylnitrone, or by inhibiting specific sources of reactive oxygen species, such as NADPH oxidases or lipoxygenases, reduced the F-actin content in the peripheral domain of growth cones. Fluorescent speckle microscopy revealed that these treatments caused actin assembly inhibition, reduced retrograde actin flow and increased contractility of actin structures in the transition zone referred to as arcs, possibly by activating the Rho pathway. Reduced levels of reactive oxygen species ultimately resulted in disassembly of the actin cytoskeleton. When neurons were cultured overnight in conditions of reduced free radicals, growth cone formation and neurite outgrowth were severely impaired. Therefore, we conclude that physiological levels of reactive oxygen species are critical for maintaining a dynamic F-actin cytoskeleton and controlling neurite outgrowth.
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Affiliation(s)
- Vidhya Munnamalai
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-2054, USA
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13
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Morino T, Ogata T, Takeba J, Yamamoto H. Microglia inhibition is a target of mild hypothermic treatment after the spinal cord injury. Spinal Cord 2008; 46:425-31. [DOI: 10.1038/sj.sc.3102163] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hamann K, Nehrt G, Ouyang H, Duerstock B, Shi R. Hydralazine inhibits compression and acrolein-mediated injuries in ex vivo spinal cord. J Neurochem 2007; 104:708-18. [PMID: 17995940 DOI: 10.1111/j.1471-4159.2007.05002.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We have previously shown that acrolein, a lipid peroxidation byproduct, is significantly increased following spinal cord injury in vivo, and that exposure to neuronal cells results in oxidative stress, mitochondrial dysfunction, increased membrane permeability, impaired axonal conductivity, and eventually cell death. Acrolein thus may be a key player in the pathogenesis of spinal cord injury, where lipid peroxidation is known to be involved. The current study demonstrates that the acrolein scavenger hydralazine protects against not only acrolein-mediated injury, but also compression in guinea pig spinal cord ex vivo. Specifically, hydralazine (500 mumol/L to 1 mmol/L) can significantly alleviate acrolein (100-500 mumol/L)-induced superoxide production, glutathione depletion, mitochondrial dysfunction, loss of membrane integrity, and reduced compound action potential conduction. Additionally, 500 mumol/L hydralazine significantly attenuated compression-mediated membrane disruptions at 2 and 3 h following injury. This was consistent with our findings that acrolein-lys adducts were increased following compression injury ex vivo, an effect that was prevented by hydralazine treatment. These findings provide further evidence for the role of acrolein in spinal cord injury, and suggest that acrolein-scavenging drugs such as hydralazine may represent a novel therapy to effectively reduce oxidative stress in disorders such as spinal cord injury and neurodegenerative diseases, where oxidative stress is known to play a role.
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Affiliation(s)
- Kristin Hamann
- Department of Basic Medical Sciences, Center for Paralysis Research, Purdue University, West Lafayette, Indiana 47907, USA
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15
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Nehrt A, Rodgers R, Shapiro S, Borgens R, Shi R. The critical role of voltage-dependent calcium channel in axonal repair following mechanical trauma. Neuroscience 2007; 146:1504-12. [PMID: 17448606 PMCID: PMC2701192 DOI: 10.1016/j.neuroscience.2007.02.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2006] [Revised: 02/07/2007] [Accepted: 02/09/2007] [Indexed: 11/30/2022]
Abstract
Membrane disruption following mechanical injury likely plays a critical role in the pathology of spinal cord trauma. It is known that intracellular calcium is a key factor that is essential to membrane resealing. However, the differential role of calcium influx through the injury site and through voltage dependent calcium channels (VDCC) has not been examined in detail. Using a well-established ex vivo guinea-pig spinal cord white matter preparation, we have found that axonal membrane resealing was significantly inhibited following transection or compression in the presence of cadmium, a non-specific calcium channel blocker, or nimodipine, a specific L-type calcium channel blocker. Membrane resealing was assessed by the changes of membrane potential and compound action potential (CAP), and exclusion of horseradish peroxidase 60 min following trauma. Furthermore, 1 microM BayK 8644, a VDCC agonist, significantly enhanced membrane resealing. Interestingly, this effect was completely abolished when the concentration of BayK 8644 was increased to 30 microM. These data suggest that VDCC play a critical role in membrane resealing. Further, there is likely an appropriate range of calcium influx through VDCC which ensures effective axonal membrane resealing. Since elevated intracellular calcium has also been linked to axonal deterioration, blockage of VDCC is proposed to be a clinical treatment for various injuries. The knowledge gained in this study will likely help us better understand the role of calcium in various CNS trauma, which is critical for designing new approaches or perhaps optimizing the effectiveness of existing methods in the treatment of CNS trauma.
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Affiliation(s)
- Ashley Nehrt
- Center for Paralysis Research, Department of Basic Medical Sciences, Weldon School of Biomedical Engineering, Purdue University
| | - Richard Rodgers
- Department of Neurosurgery, School of Medicine, Indiana University
| | - Scott Shapiro
- Department of Neurosurgery, School of Medicine, Indiana University
| | - Richard Borgens
- Center for Paralysis Research, Department of Basic Medical Sciences, Weldon School of Biomedical Engineering, Purdue University
| | - Riyi Shi
- Center for Paralysis Research, Department of Basic Medical Sciences, Weldon School of Biomedical Engineering, Purdue University
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Bernards CM, Akers T. Effect of postinjury intravenous or intrathecal methylprednisolone on spinal cord excitatory amino-acid release, nitric oxide generation, PGE2 synthesis, and myeloperoxidase content in a pig model of acute spinal cord injury. Spinal Cord 2006; 44:594-604. [PMID: 16432531 DOI: 10.1038/sj.sc.3101891] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
STUDY DESIGN Prospective, randomized, in vivo acute spinal cord injury in pigs. SETTING Department of Anesthesiology, University of Washington, Seattle, WA, USA. OBJECTIVES To determine whether postinjury methylprednisolone could reduce the generation of known mediators of secondary neurological injury. METHODS Intrathecal microdialysis probes were used to sample cerebrospinal fluid (CSF) for measurement of PGE(2), glutamate, and citrulline (a byproduct of nitric oxide generation), before and after spinal cord injury in anesthetized pigs. The spinal cord was removed at the end of the study for measurement of myeloperoxidase and methylprednisolone concentrations. Animals were randomly allocated to receive intravenous methylprednisolone (30 mg/kg bolus then 3.4 mg/kg/h), intrathecal methylprednisolone (5 mg bolus then 5 mg/h), or saline, beginning 30 min after the spinal cord was injured by using a modification of the Allen weight drop technique. RESULTS Spinal cord injury significantly increased the amount of glutamate, PGE(2), myeloperoxidase, and citrulline, recovered from the CSF dialysates. However, neither intravenous nor intrathecal methylprednisolone administered after injury had any effect on the magnitude of the increase in any of the measured biochemicals. Intrathecal methylprednisolone administration produced a spinal cord methylprednisolone concentration that was eight times greater, and a plasma concentration that was 32 times less, than that achieved with intravenous administration. CONCLUSIONS Contrary to earlier animal studies in which methylprednisolone was administered either before or immediately after spinal cord injury, we found no effect of intravenous or intrathecal methylprednisolone on any of the parameters measured when administered 30 min postinjury.
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Affiliation(s)
- C M Bernards
- Department of Anesthesiology, Anesthesiology Faculty, Virginia Mason Medical Center, University of Washington, Seattle, WA, USA
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Tribus M, Galehr J, Trojer P, Brosch G, Loidl P, Marx F, Haas H, Graessle S. HdaA, a major class 2 histone deacetylase of Aspergillus nidulans, affects growth under conditions of oxidative stress. EUKARYOTIC CELL 2005; 4:1736-45. [PMID: 16215180 PMCID: PMC1265891 DOI: 10.1128/ec.4.10.1736-1745.2005] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Histone deacetylases (HDACs) catalyze the removal of acetyl groups from the epsilon-amino group of distinct lysine residues in the amino-terminal tail of core histones. Since the acetylation status of core histones plays a crucial role in fundamental processes in eukaryotic organisms, such as replication and regulation of transcription, recent research has focused on the enzymes responsible for the acetylation/deacetylation of core histones. Very recently, we showed that HdaA, a member of the Saccharomyces cerevisiae HDA1-type histone deacetylases, is a substantial contributor to total HDAC activity in the filamentous fungus Aspergillus nidulans. Now we demonstrate that deletion of the hdaA gene indeed results in the loss of the main activity peak and in a dramatic reduction of total HDAC activity. In contrast to its orthologs in yeast and higher eukaryotes, HdaA has strong intrinsic activity as a protein monomer when expressed as a recombinant protein in a prokaryotic expression system. In vivo, HdaA is involved in the regulation of enzymes which are of vital importance for the cellular antioxidant response in A. nidulans. Consequently, deltahdaA strains exhibit significantly reduced growth on substrates whose catabolism generates molecules responsible for oxidative stress conditions in the fungus. Our analysis revealed that reduced expression of the fungal catalase CatB is jointly responsible for the significant growth reduction of the hdaA mutant strains.
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Affiliation(s)
- Martin Tribus
- Division of Molecular Biology, Biocenter, Innsbruck Medical University, Fritz-Pregl Strasse 3, A-6020 Innsbruck, Austria
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Caggiano AO, Zimber MP, Ganguly A, Blight AR, Gruskin EA. Chondroitinase ABCI improves locomotion and bladder function following contusion injury of the rat spinal cord. J Neurotrauma 2005; 22:226-39. [PMID: 15716629 DOI: 10.1089/neu.2005.22.226] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Chondroitin sulfate proteoglycans are synthesized and deposited in the spinal cord following injury. These proteoglycans may restrict regeneration and plasticity and contribute to the limited recovery seen after an injury. Chondroitinase, a bacterial enzyme that catalyzes the hydrolysis of the chondroitin chains on proteoglycans, has been shown to improve motor and sensory function following partial transection lesions of the spinal cord. To assess the effects of chondroitinase in a clinically relevant model of spinal cord injury, 128 female Long-Evans rats received either a severe, moderate, or mild contusion injury at the vertebral level T9/T10 with a forceps model and were treated for 2 weeks with chondroitinase ABCI at 0.06 Units per dose, penicillinase, or vehicle control via an intrathecal catheter placed near the injury. Motor behavior was measured by open-field testing of locomotion and bladder function monitored by measuring daily residual urine volumes. Animals treated with chondroitinase showed significant improvements in open-field locomotor activity as measured by the Basso, Beattie and Bresnahan scoring system after both severe and moderate SCI (p<0.05 and 0.01, respectively). No significant locomotor differences were observed in the mild injury group. In the moderate injury group, residual urine volumes were reduced with chondroitinase treatment by 2 weeks after injury (p<0.05) and in the severe injury group, by 6 weeks after injury (NS). These results demonstrate that chondroitinase is effective at promoting both somatic and autonomic motor recovery following a clinically relevant contusion spinal cord injury and is a candidate as a therapeutic for human spinal cord injury.
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Yune TY, Lee SM, Kim SJ, Park HK, Oh YJ, Kim YC, Markelonis GJ, Oh TH. Manganese superoxide dismutase induced by TNF-beta is regulated transcriptionally by NF-kappaB after spinal cord injury in rats. J Neurotrauma 2005; 21:1778-94. [PMID: 15684769 DOI: 10.1089/neu.2004.21.1778] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Antioxidant enzymes including superoxide dismutase (SOD) may play a role in the mechanism by which cells counteract the deleterious effects of reactive oxygen species (ROS) after spinal cord injury (SCI). Cu/Zn and MnSOD are especially potent scavengers of superoxide anion and likely serve important cytoprotective roles against cellular damage. We investigated expression of SOD after SCI to address its role during the early stages of injury. MnSOD activity was increased 4 h after SCI and persisted at elevated levels up to 24-48 h; by contrast, Cu/ZnSOD activity was not changed. RT-PCR and Western blot analyses showed increased levels of MnSOD mRNA and protein, respectively, by 4 h and reached maximum levels by 24-48 h. Double immunostaining revealed that MnSOD protein was localized within neurons and oligodendrocytes. Tumor necrosis factor-alpha (TNF-alpha) was administered locally into uninjured spinal cords to examine potential mechanisms for MnSOD induction after injury. TNF-alpha administered exogenously increased MnSOD expression in uninjured spinal cords. Western blot and immunostaining also revealed that a transcription factor, NF-kappaB, was activated and translocated into the nuclei of neurons and oligodendrocytes. By contrast, administration of neutralizing antibody against TNF-alpha into injured spinal cords attenuated the increase in MnSOD expression and activation of NF-kappaB. Double immunostaining revealed that MnSOD was co-localized with NF-kappaB in neurons and oligodendrocytes after SCI. These results suggest that TNF-alpha may be an inducer of NF-kappaB activation and MnSOD expression after SCI and that MnSOD expression induced by TNF-alpha is likely mediated through activation of NF-kappaB.
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Affiliation(s)
- Tae Y Yune
- Biomedical Research Center, Korea Institute of Science & Technology, Seoul, Korea.
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Xu W, Chi L, Xu R, Ke Y, Luo C, Cai J, Qiu M, Gozal D, Liu R. Increased production of reactive oxygen species contributes to motor neuron death in a compression mouse model of spinal cord injury. Spinal Cord 2005; 43:204-13. [PMID: 15520836 DOI: 10.1038/sj.sc.3101674] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
STUDY DESIGN Experimental laboratory investigation of the role and pathways of reactive oxygen species (ROS)-mediated motor neuron cell death in a mouse model of compression spinal cord injury. OBJECTIVES To analyze ROS-mediated oxidative stress propagation and signal transduction leading to motor neuron apoptosis induced by compression spinal cord injury. SETTING University of Louisville Health Science Center. METHODS Adult C57BL/6J mice and transgenic mice overexpressing SOD1 were severely lesioned at the lumbar region by compression spinal cord injury approach. Fluorescent oxidation, oxidative response gene expression and oxidative stress damage markers were used to assay spinal cord injury-mediated ROS generation and oxidative stress propagation. Biochemical and immunohistochemical analyses were applied to define the ROS-mediated motor neuron apoptosis resulted from compression spinal cord injury. RESULTS ROS production was shown to be elevated in the lesioned spinal cord as detected by fluorescent oxidation assays. The early oxidative stress response markers, NF-kappaB transcriptional activation and c-Fos gene expression, were significantly increased after spinal cord injury. Lipid peroxidation and nucleic acid oxidation were also elevated in the lesioned spinal cord and motor neurons. Cytochrome c release, caspase-3 activation and apoptotic cell death were increased in the spinal cord motor neuron cells after spinal cord injury. On the other hand, transgenic mice overexpressing SOD1 showed lower levels of steady-state ROS production and reduction of motor neuron apoptosis compared to that of control mice after spinal cord injury. CONCLUSION These data together provide direct evidence to demonstrate that the increased production of ROS is an early and likely causal event that contributes to the spinal cord motor neuron death following spinal cord injury. Thus, antioxidants/antioxidant enzyme intervention combined with other therapy may provide an effective approach to alleviate spinal cord injury-induced motor neuron damage and motor dysfunction.
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Affiliation(s)
- W Xu
- Department of Pediatrics, Kosair Children's Hospital Research Institute, University of Louisville, Louisville, KY 40202, USA
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Peasley MA, Shi R. Ischemic insult exacerbates acrolein-induced conduction loss and axonal membrane disruption in guinea pig spinal cord white matter. J Neurol Sci 2003; 216:23-32. [PMID: 14607299 DOI: 10.1016/s0022-510x(03)00201-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Cellular destruction following ischemic insult may be due to secondary injury mechanisms, not the oxygen-glucose deprivation itself. We have examined the effect of acrolein, an aldehyde product of lipid peroxidation (LPO) and oxidative stress, on the axons in isolated guinea pig spinal cord white matter following ischemic insult. We have found that acrolein at 50 microM, which is unharmful to spinal cord when applied alone, causes action potential conduction failure and membrane disruption following 1 to 2 h of exposure when applied during the reperfusion period. Ischemic insult also exacerbates the effect of acrolein at 200 microM, which does inflict functional and anatomical damage when applied alone. Unlike metabolic poisoning, acrolein-mediated damage is not a function of axonal size and does not affect the refractoriness in response to dual and multiple stimuli. These results indicate that spinal cord axons, in addition to experiencing elevated free radicals, are more vulnerable to acrolein attack when the level of oxygen and glucose is low. We conclude that free radicals and lipid peroxidation in general, and acrolein in specific, may play a critical role in cellular destruction and functional loss in such injury.
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Affiliation(s)
- Melissa A Peasley
- Department of Basic Medical Sciences, Center for Paralysis Research, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA
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