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Hubbard WB, Velmurugan GV, Sullivan PG. The role of mitochondrial uncoupling in the regulation of mitostasis after traumatic brain injury. Neurochem Int 2024; 174:105680. [PMID: 38311216 PMCID: PMC10922998 DOI: 10.1016/j.neuint.2024.105680] [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: 11/03/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/10/2024]
Abstract
Mitostasis, the maintenance of healthy mitochondria, plays a critical role in brain health. The brain's high energy demands and reliance on mitochondria for energy production make mitostasis vital for neuronal function. Traumatic brain injury (TBI) disrupts mitochondrial homeostasis, leading to secondary cellular damage, neuronal degeneration, and cognitive deficits. Mild mitochondrial uncoupling, which dissociates ATP production from oxygen consumption, offers a promising avenue for TBI treatment. Accumulating evidence, from endogenous and exogenous mitochondrial uncoupling, suggests that mitostasis is closely regulating by mitochondrial uncoupling and cellular injury environments may be more sensitive to uncoupling. Mitochondrial uncoupling can mitigate calcium overload, reduce oxidative stress, and induce mitochondrial proteostasis and mitophagy, a process that eliminates damaged mitochondria. The interplay between mitochondrial uncoupling and mitostasis is ripe for further investigation in the context of TBI. These multi-faceted mechanisms of action for mitochondrial uncoupling hold promise for TBI therapy, with the potential to restore mitochondrial health, improve neurological outcomes, and prevent long-term TBI-related pathology.
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Affiliation(s)
- W Brad Hubbard
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA; Department of Physiology, University of Kentucky, Lexington, KY, USA; Lexington Veterans' Affairs Healthcare System, Lexington, KY, USA.
| | - Gopal V Velmurugan
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA; Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Patrick G Sullivan
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, KY, USA; Lexington Veterans' Affairs Healthcare System, Lexington, KY, USA; Department of Neuroscience, University of Kentucky, Lexington, KY, USA.
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2
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Pinelis V, Krasilnikova I, Bakaeva Z, Surin A, Boyarkin D, Fisenko A, Krasilnikova O, Pomytkin I. Insulin Diminishes Superoxide Increase in Cytosol and Mitochondria of Cultured Cortical Neurons Treated with Toxic Glutamate. Int J Mol Sci 2022; 23:ijms232012593. [PMID: 36293449 PMCID: PMC9604026 DOI: 10.3390/ijms232012593] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/12/2022] [Accepted: 10/14/2022] [Indexed: 11/17/2022] Open
Abstract
Glutamate excitotoxicity is involved in the pathogenesis of many disorders, including stroke, traumatic brain injury, and Alzheimer’s disease, for which central insulin resistance is a comorbid condition. Neurotoxicity of glutamate (Glu) is primarily associated with hyperactivation of the ionotropic N-methyl-D-aspartate receptors (NMDARs), causing a sustained increase in intracellular free calcium concentration ([Ca2+]i) and synchronous mitochondrial depolarization and an increase in intracellular superoxide anion radical (O2–•) production. Recently, we found that insulin protects neurons against excitotoxicity by decreasing the delayed calcium deregulation (DCD). However, the role of insulin in O2–• production in excitotoxicity still needs to be clarified. The present study aims to investigate insulin’s effects on glutamate-evoked O2–• generation and DCD using the fluorescent indicators dihydroethidium, MitoSOX Red, and Fura-FF in cortical neurons. We found a linear correlation between [Ca2+]i and [O2–•] in primary cultures of the rat neuron exposed to Glu, with insulin significantly reducing the production of intracellular and mitochondrial O2–• in the primary cultures of the rat neuron. MK 801, an inhibitor of NMDAR-gated Ca2+ influx, completely abrogated the glutamate effects in both the presence and absence of insulin. In experiments in sister cultures, insulin diminished neuronal death and O2 consumption rate (OCR).
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Affiliation(s)
- Vsevolod Pinelis
- Laboratory of Neurobiology, National Medical Research Center of Children’s Health, Russian Ministry of Health, Lomonosov Avenue 2, Bldg 1, 119991 Moscow, Russia
- Correspondence: (V.P.); (I.P.)
| | - Irina Krasilnikova
- Laboratory of Neurobiology, National Medical Research Center of Children’s Health, Russian Ministry of Health, Lomonosov Avenue 2, Bldg 1, 119991 Moscow, Russia
| | - Zanda Bakaeva
- Laboratory of Neurobiology, National Medical Research Center of Children’s Health, Russian Ministry of Health, Lomonosov Avenue 2, Bldg 1, 119991 Moscow, Russia
- Department of General Biology and Physiology, Kalmyk State University Named after B.B. Gorodovikov, St. Pushkin, 11, 358000 Elista, Russia
| | - Alexander Surin
- Laboratory of Neurobiology, National Medical Research Center of Children’s Health, Russian Ministry of Health, Lomonosov Avenue 2, Bldg 1, 119991 Moscow, Russia
- Laboratory of Pathology of Ion Transport and Intracellular Signaling, Institute of General Pathology and Pathophysiology, Baltiyskaya St., 8, 125315 Moscow, Russia
| | - Dmitrii Boyarkin
- Laboratory of Neurobiology, National Medical Research Center of Children’s Health, Russian Ministry of Health, Lomonosov Avenue 2, Bldg 1, 119991 Moscow, Russia
| | - Andrei Fisenko
- Laboratory of Neurobiology, National Medical Research Center of Children’s Health, Russian Ministry of Health, Lomonosov Avenue 2, Bldg 1, 119991 Moscow, Russia
| | - Olga Krasilnikova
- Department of Regenerative Medicine, National Medical Research Radiological Center, 4 Koroleva St., 249036 Obninsk, Russia
| | - Igor Pomytkin
- Institute of Pharmacy, The First Sechenov Moscow State Medical University under Ministry of Health of the Russian Federation, St. Trubetskaya, 8, Bldg 2, 119991 Moscow, Russia
- Correspondence: (V.P.); (I.P.)
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Astaxanthin Protection against Neuronal Excitotoxicity via Glutamate Receptor Inhibition and Improvement of Mitochondrial Function. Mar Drugs 2022; 20:md20100645. [PMID: 36286468 PMCID: PMC9605357 DOI: 10.3390/md20100645] [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: 08/30/2022] [Revised: 10/03/2022] [Accepted: 10/11/2022] [Indexed: 11/17/2022] Open
Abstract
Excitotoxicity is known to associate with neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, Amyotrophic lateral sclerosis and Huntington’s disease, as well as aging, stroke, trauma, ischemia and epilepsy. Excessive release of glutamate, overactivation of glutamate receptors, calcium overload, mitochondrial dysfunction and excessive reactive oxygen species (ROS) formation are a few of the suggested key mechanisms. Astaxanthin (AST), a carotenoid, is known to act as an antioxidant and protect neurons from excitotoxic injuries. However, the exact molecular mechanism of AST neuroprotection is not clear. Thus, in this study, we investigated the role of AST in neuroprotection in excitotoxicity. We utilized primary cortical neuronal culture and live cell fluorescence imaging for the study. Our results suggest that AST prevents neuronal death, reduces ROS formation and decreases the abnormal mitochondrial membrane depolarization induced by excitotoxic glutamate insult. Additionally, AST modulates intracellular calcium levels by inhibiting peak and irreversible secondary sustained calcium levels in neurons. Furthermore, AST regulates the ionotropic glutamate subtype receptors NMDA, AMPA, KA and mitochondrial calcium. Moreover, AST decreases NMDA and AMPA receptor protein expression levels, while KA remains unaffected. Overall, our results indicate that AST protects neurons from excitotoxic neuronal injury by regulating ionotropic glutamate receptors, cytosolic secondary calcium rise and mitochondrial calcium buffering. Hence, AST could be a promising therapeutic agent against excitotoxic insults in neurodegenerative diseases.
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Amina M, Bhat RS, Al-Dbass AM, Musayeib NM, Fahmy R, Alhadlaq L, El-Ansary A. The protective effect of Moringa oleifera plant extract against glutamate-induced DNA damage and reduced cell viability in a primary retinal ganglion cell line. PeerJ 2021; 9:e11569. [PMID: 34221717 PMCID: PMC8231317 DOI: 10.7717/peerj.11569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/16/2021] [Indexed: 12/22/2022] Open
Abstract
Background Glutamate excitotoxicity can cause DNA damage and is linked to many retinal and neurological disorders. In mammals, the visual signal from the eyes to the brain is conducted only by retinal ganglion cells (RGCs), which can be damaged by overstimulation of glutamate receptors. Methodology We examined the protective effects of Moringa oleifera seed extract against glutamate-induced DNA damage in RGCs. RGCs cells were treated with 5, 10, 50, or 100 µg/ml of M. oleifera seed extract and glutamate separately and then assessed for DNA damage using the comet assay. We also evaluated the viability of the RGCs after both treatments using the MTT test. Additionally, RGCs were pretreated with M. oleifera seed extract (50 or 100 µg/ml) for 2 h before glutamate treatment (100 µg/ml) to determine the potential protective effects of M. oleifera. We performed a phytochemical analysis of the M. oleifera seed extract using standard reactions. Results The M. oleifera seed extract was found to be rich in many phytochemicals. We observed a significant dose-dependent elevation in all comet assay variables in glutamate-treated RGCs, whereas M. oleifera seed extract treatments did not show any significant change in DNA integrity. Conclusion M. oleifera seed extract demonstrates neuroprotective effects, which suggests it may help to prevent the development of many neurodegenerative disorders.
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Affiliation(s)
- Musarat Amina
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Ramesa Shafi Bhat
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Abeer M Al-Dbass
- Department of Biochemistry, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Nawal M Musayeib
- Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Rania Fahmy
- Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, r, Saudi Arabia.,Department of Ophthalmology, Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Leen Alhadlaq
- College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Afaf El-Ansary
- Central Laboratory, King Saud University, Riyadh, Saudi Arabia
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5
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Andreasen M, Nedergaard S. Effect of acute mitochondrial dysfunction on hyperexcitable network activity in rat hippocampus in vitro. Brain Res 2020; 1751:147193. [PMID: 33157100 DOI: 10.1016/j.brainres.2020.147193] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 11/15/2022]
Abstract
Metabolic stress imposed by epileptic seizures can result in mitochondrial dysfunction, believed to act as positive feedback on epileptogenesis and seizure susceptibility. As the mechanism behind this positive feedback is unclear, the aim of the present study was to investigate the causal link between acute mitochondrial dysfunction and increased seizure susceptibility in hyperexcitable hippocampal networks. Following the induction of spontaneous interictal-like discharges, acute selective pharmacological blockade of either of the mitochondrial respiratory complexes (MRC) I-IV induced seizure-like events (SLE) in 78-100% of experiments. A similar result was obtained by uncoupling the oxidative phosphorylation (OXPHOS) but not by selective blockade of MRCV (ATP synthase) which did not induce SLE. The reactive oxygen species (ROS) scavenger 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (tempol, 2 mM) significantly reduced the proconvulsant effect of blocking MRCI but did not reduce the proconvulsant effect of OXPHOS uncoupling. These findings indicate that acute mitochondrial dysfunction can lead to a convulsive state within a short timeframe, and that increased ROS production makes substantial contribution to such induction in addition to other mitochondrial related factors, which appears to be independent of changes in ROS and ATP production.
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Affiliation(s)
- Mogens Andreasen
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Steen Nedergaard
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark
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6
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Wang J, Swanson RA. Superoxide and Non-ionotropic Signaling in Neuronal Excitotoxicity. Front Neurosci 2020; 4:861. [PMID: 33013314 PMCID: PMC7497801 DOI: 10.3389/fnins.2020.00861] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 07/24/2020] [Indexed: 01/24/2023] Open
Abstract
Excitotoxicity is classically attributed to Ca2+ influx through NMDA receptors (NMDAr), leading to production of nitric oxide by neuronal nitric oxide synthase and superoxide by mitochondria, which react to form highly cytotoxic peroxynitrite. More recent observations warrant revision of the classic view and help to explain some otherwise puzzling aspects of excitotoxic cell injury. Studies using pharmacological and genetic approaches show that superoxide produced by NMDAr activation originates primarily from NADPH oxidase rather than from mitochondria. As NADPH oxidase is localized to the plasma membrane, this also provides an explanation for the extracellular release of superoxide and cell-to-cell “spread” of excitotoxic injury observed in vitro and in vivo. The signaling pathway linking NMDAr to NADPH oxidase involves Ca2+ influx, phosphoinositol-3-kinase, and protein kinase Cζ, and interventions at any of these steps can prevent superoxide production and excitotoxic injury. Ca2+ influx specifically through NMDAr is normally required to induce excitotoxicity, through a mechanism presumed to involve privileged Ca2+ access to local signaling domains. However, experiments using selective blockade of the NMDAr ion channel and artificial reconstitution of Ca2+ by other routes indicate that the special effects of NMDAr activation are attributable instead to concurrent non-ionotropic NMDAr signaling by agonist binding to NMDAr. The non-ionotropic signaling driving NADPH oxidase activation is mediated in part by phosphoinositol-3-kinase binding to the C-terminal domain of GluN2B receptor subunits. These more recently identified aspects of excitotoxicity expand our appreciation of the complexity of excitotoxic processes and suggest novel approaches for limiting neuronal injury.
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Affiliation(s)
- Jiejie Wang
- Department of Neurology, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, San Francisco, CA, United States
| | - Raymond A Swanson
- Department of Neurology, University of California, San Francisco, and San Francisco Veterans Affairs Health Care System, San Francisco, CA, United States
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Khaw YM, Cunningham C, Tierney A, Sivaguru M, Inoue M. Neutrophil-selective deletion of Cxcr2 protects against CNS neurodegeneration in a mouse model of multiple sclerosis. J Neuroinflammation 2020; 17:49. [PMID: 32019585 PMCID: PMC7001284 DOI: 10.1186/s12974-020-1730-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 01/30/2020] [Indexed: 11/10/2022] Open
Abstract
Background Multiple sclerosis (MS) is a chronic debilitating immune-mediated disease of the central nervous system (CNS) driven by demyelination and gray matter neurodegeneration. We previously reported an experimental autoimmune encephalomyelitis (EAE) MS mouse model with elevated serum CXCL1 that developed severe and prolonged neuron damage. Our findings suggested that CXCR2 signaling may be important in neuronal damage, thus implicating neutrophils, which express CXCR2 in abundance, as a potential cell type involved. The goals of this study were to determine if CXCR2 signaling in neutrophils mediate neuronal damage and to identify potential mechanisms of damage. Methods EAE was induced in wild-type control and neutrophil-specific Cxcr2 knockout (Cxcr2 cKO) mice by repeated high-dose injections of heat-killed Mycobacterium tuberculosis and MOG35–55 peptide. Mice were examined daily for motor deficit. Serum CXCL1 level was determined at different time points throughout disease development. Neuronal morphology in Golgi-Cox stained lumbar spinal cord ventral horn was assessed using recently developed confocal reflection super-resolution technique. Immune cells from CNS and lymphoid organs were quantified by flow cytometry. CNS-derived neutrophils were co-cultured with neuronal crest cells and neuronal cell death was measured. Neutrophils isolated from lymphoid organs were examined for expression of reactive oxygen species (ROS) and ROS-related genes. Thioglycolate-activated neutrophils were isolated, treated with recombinant CXCL1, and measured for ROS production. Results Cxcr2 cKO mice had less severe disease symptoms at peak and late phase when compared to control mice with similar levels of CNS-infiltrating neutrophils and other immune cells despite high levels of circulating CXCL1. Additionally, Cxcr2 cKO mice had significantly reduced CNS neuronal damage in the ventral horn of the spinal cord. Neutrophils isolated from control EAE mice induced vast neuronal cell death in vitro when compared with neutrophils isolated from Cxcr2 cKO EAE mice. Neutrophils isolated from control EAE mice, but not Cxcr2 cKO mice, exhibited elevated ROS generation, in addition to heightened Ncf1 and Il1b transcription. Furthermore, recombinant CXCL1 was sufficient to significantly increase neutrophils ROS production. Conclusions CXCR2 signal in neutrophils is critical in triggering CNS neuronal damage via ROS generation, which leads to prolonged EAE disease. These findings emphasize that CXCR2 signaling in neutrophils may be a viable target for therapeutic intervention against CNS neuronal damage.
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Affiliation(s)
- Yee Ming Khaw
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Claire Cunningham
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,The School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Abigail Tierney
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,The School of Molecular and Cellular Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Mayandi Sivaguru
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Makoto Inoue
- Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA. .,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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8
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Spector C, Mele AR, Wigdahl B, Nonnemacher MR. Genetic variation and function of the HIV-1 Tat protein. Med Microbiol Immunol 2019; 208:131-169. [PMID: 30834965 DOI: 10.1007/s00430-019-00583-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 02/11/2019] [Indexed: 12/14/2022]
Abstract
Human immunodeficiency virus type 1 (HIV-1) encodes a transactivator of transcription (Tat) protein, which has several functions that promote viral replication, pathogenesis, and disease. Amino acid variation within Tat has been observed to alter the functional properties of Tat and, depending on the HIV-1 subtype, may produce Tat phenotypes differing from viruses' representative of each subtype and commonly used in in vivo and in vitro experimentation. The molecular properties of Tat allow for distinctive functional activities to be determined such as the subcellular localization and other intracellular and extracellular functional aspects of this important viral protein influenced by variation within the Tat sequence. Once Tat has been transported into the nucleus and becomes engaged in transactivation of the long terminal repeat (LTR), various Tat variants may differ in their capacity to activate viral transcription. Post-translational modification patterns based on these amino acid variations may alter interactions between Tat and host factors, which may positively or negatively affect this process. In addition, the ability of HIV-1 to utilize or not utilize the transactivation response (TAR) element within the LTR, based on genetic variation and cellular phenotype, adds a layer of complexity to the processes that govern Tat-mediated proviral DNA-driven transcription and replication. In contrast, cytoplasmic or extracellular localization of Tat may cause pathogenic effects in the form of altered cell activation, apoptosis, or neurotoxicity. Tat variants have been shown to differentially induce these processes, which may have implications for long-term HIV-1-infected patient care in the antiretroviral therapy era. Future studies concerning genetic variation of Tat with respect to function should focus on variants derived from HIV-1-infected individuals to efficiently guide Tat-targeted therapies and elucidate mechanisms of pathogenesis within the global patient population.
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Affiliation(s)
- Cassandra Spector
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N 15th St, Philadelphia, PA, 19102, USA
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Anthony R Mele
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N 15th St, Philadelphia, PA, 19102, USA
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Brian Wigdahl
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N 15th St, Philadelphia, PA, 19102, USA
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA
- Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Michael R Nonnemacher
- Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N 15th St, Philadelphia, PA, 19102, USA.
- Center for Molecular Virology and Translational Neuroscience, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, Philadelphia, PA, USA.
- Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA.
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Reutov VP, Samosudova NV, Sorokina EG. A Model of Glutamate Neurotoxicity and Mechanisms of the Development of the Typical Pathological Process. Biophysics (Nagoya-shi) 2019. [DOI: 10.1134/s0006350919020143] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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10
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Hill RL, Singh IN, Wang JA, Hall ED. Effects of Phenelzine Administration on Mitochondrial Function, Calcium Handling, and Cytoskeletal Degradation after Experimental Traumatic Brain Injury. J Neurotrauma 2018; 36:1231-1251. [PMID: 30358485 DOI: 10.1089/neu.2018.5946] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Traumatic brain injury (TBI) results in the production of peroxynitrite (PN), leading to oxidative damage of lipids and protein. PN-mediated lipid peroxidation (LP) results in production of reactive aldehydes 4-hydroxynonenal (4-HNE) and acrolein. The goal of these studies was to explore the hypothesis that interrupting secondary oxidative damage following a TBI via phenelzine (PZ), analdehyde scavenger, would protect against LP-mediated mitochondrial and neuronal damage. Male Sprague-Dawley rats received a severe (2.2 mm) controlled cortical impact (CCI)-TBI. PZ was administered subcutaneously (s.c.) at 15 min (10 mg/kg) and 12 h (5 mg/kg) post-injury and for the therapeutic window/delay study, PZ was administered at 1 h (10 mg/kg) and 24 h (5 mg/kg). Mitochondrial and cellular protein samples were obtained at 24 and 72 h post-injury (hpi). Administration of PZ significantly improved mitochondrial respiration at 24 and 72 h compared with vehicle-treated animals. These results demonstrate that PZ administration preserves mitochondrial bioenergetics at 24 h and that this protection is maintained out to 72 hpi. Additionally, delaying the administration still elicited significant protective effects. PZ administration also improved mitochondrial Ca2+ buffering (CB) capacity and mitochondrial membrane potential parameters compared with vehicle-treated animals at 24 h. Although PZ treatment attenuated aldehyde accumulation post-injury, the effects were insignificant. The amount of α-spectrin breakdown in cortical tissue was reduced by PZ administration at 24 h, but not at 72 hpi compared with vehicle-treated animals. In conclusion, these results indicate that acute PZ treatment successfully attenuates LP-mediated oxidative damage eliciting multiple neuroprotective effects following TBI.
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Affiliation(s)
- Rachel L Hill
- 1 Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, Lexington, Kentucky
| | - Indrapal N Singh
- 1 Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, Lexington, Kentucky.,2 Department of Neuroscience, University of Kentucky College of Medicine, Lexington, Kentucky
| | - Juan A Wang
- 1 Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, Lexington, Kentucky
| | - Edward D Hall
- 1 Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, Lexington, Kentucky.,2 Department of Neuroscience, University of Kentucky College of Medicine, Lexington, Kentucky
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11
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Hill RL, Kulbe JR, Singh IN, Wang JA, Hall ED. Synaptic Mitochondria are More Susceptible to Traumatic Brain Injury-induced Oxidative Damage and Respiratory Dysfunction than Non-synaptic Mitochondria. Neuroscience 2018; 386:265-283. [PMID: 29960045 DOI: 10.1016/j.neuroscience.2018.06.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 06/12/2018] [Accepted: 06/18/2018] [Indexed: 12/17/2022]
Abstract
Traumatic brain injury (TBI) results in mitochondrial dysfunction and induction of lipid peroxidation (LP). Lipid peroxidation-derived neurotoxic aldehydes such as 4-HNE and acrolein bind to mitochondrial proteins, inducing additional oxidative damage and further exacerbating mitochondrial dysfunction and LP. Mitochondria are heterogeneous, consisting of both synaptic and non-synaptic populations. Synaptic mitochondria are reported to be more vulnerable to injury; however, this is the first study to characterize the temporal profile of synaptic and non-synaptic mitochondria following TBI, including investigation of respiratory dysfunction and oxidative damage to mitochondrial proteins between 3 and 120 h following injury. These results indicate that synaptic mitochondria are indeed the more vulnerable population, showing both more rapid and severe impairments than non-synaptic mitochondria. By 24 h, synaptic respiration is significantly impaired compared to synaptic sham, whereas non-synaptic respiration does not decline significantly until 48 h. Decreases in respiration are associated with increases in oxidative damage to synaptic and non-synaptic mitochondrial proteins at 48 h and 72 h, respectively. These results indicate that the therapeutic window for mitochondria-targeted pharmacological neuroprotectants to prevent respiratory dysfunction is shorter for the more vulnerable synaptic mitochondria than for the non-synaptic population.
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Affiliation(s)
- Rachel L Hill
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States
| | - Jacqueline R Kulbe
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States; Department of Neuroscience, University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States
| | - Indrapal N Singh
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States; Department of Neuroscience, University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States
| | - Juan A Wang
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States
| | - Edward D Hall
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States; Department of Neuroscience, University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States.
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12
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Anilkumar U, Weisova P, Schmid J, Bernas T, Huber HJ, Düssmann H, Connolly NMC, Prehn JHM. Defining external factors that determine neuronal survival, apoptosis and necrosis during excitotoxic injury using a high content screening imaging platform. PLoS One 2017; 12:e0188343. [PMID: 29145487 PMCID: PMC5690623 DOI: 10.1371/journal.pone.0188343] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 11/06/2017] [Indexed: 12/27/2022] Open
Abstract
Cell death induced by excessive glutamate receptor overactivation, excitotoxicity, has been implicated in several acute and chronic neurological disorders. While numerous studies have demonstrated the contribution of biochemically and genetically activated cell death pathways in excitotoxic injury, the factors mediating passive, excitotoxic necrosis are less thoroughly investigated. To address this question, we developed a high content screening (HCS) based assay to collect high volumes of quantitative cellular imaging data and elucidated the effects of intrinsic and external factors on excitotoxic necrosis and apoptosis. The analysis workflow consisted of robust nuclei segmentation, tracking and a classification algorithm, which enabled automated analysis of large amounts of data to identify and quantify viable, apoptotic and necrotic neuronal populations. We show that mouse cerebellar granule neurons plated at low or high density underwent significantly increased necrosis compared to neurons seeded at medium density. Increased extracellular Ca2+ sensitized neurons to glutamate-induced excitotoxicity, but surprisingly potentiated cell death mainly through apoptosis. We also demonstrate that inhibition of various cell death signaling pathways (including inhibition of calpain, PARP and AMPK activation) primarily reduced excitotoxic apoptosis. Excitotoxic necrosis instead increased with low extracellular glucose availability. Our study is the first of its kind to establish and implement a HCS based assay to investigate the contribution of external and intrinsic factors to excitotoxic apoptosis and necrosis.
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Affiliation(s)
- Ujval Anilkumar
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Petronela Weisova
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Jasmin Schmid
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Tytus Bernas
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Heinrich J. Huber
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Heiko Düssmann
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Niamh M. C. Connolly
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Jochen H. M. Prehn
- Department of Physiology and Medical Physics and RCSI Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
- * E-mail:
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13
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Qaid E, Zakaria R, Sulaiman SF, Yusof NM, Shafin N, Othman Z, Ahmad AH, Aziz CA. Insight into potential mechanisms of hypobaric hypoxia-induced learning and memory deficit - Lessons from rat studies. Hum Exp Toxicol 2017; 36:1315-1325. [PMID: 28111974 DOI: 10.1177/0960327116689714] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Impairment of memory is one of the most frequently reported symptoms during sudden hypoxia exposure in human. Cortical atrophy has been linked to the impaired memory function and is suggested to occur with chronic high-altitude exposure. However, the precise molecular mechanism(s) of hypoxia-induced memory impairment remains an enigma. In this work, we review hypoxia-induced learning and memory deficit in human and rat studies. Based on data from rat studies using different protocols of continuous hypoxia, we try to elicit potential mechanisms of hypobaric hypoxia-induced memory deficit.
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Affiliation(s)
- Eya Qaid
- 1 Department of Physiology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - R Zakaria
- 1 Department of Physiology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - S F Sulaiman
- 2 School of Biological Sciences, Universiti Sains Malaysia, Penang, Malaysia
| | - Na Mohd Yusof
- 3 Department of Anatomy, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - N Shafin
- 1 Department of Physiology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Z Othman
- 4 Department of Psychiatry, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - A H Ahmad
- 1 Department of Physiology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
| | - Cb Abd Aziz
- 1 Department of Physiology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia
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14
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Beckhauser TF, Francis-Oliveira J, De Pasquale R. Reactive Oxygen Species: Physiological and Physiopathological Effects on Synaptic Plasticity. J Exp Neurosci 2016; 10:23-48. [PMID: 27625575 PMCID: PMC5012454 DOI: 10.4137/jen.s39887] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 08/09/2016] [Accepted: 08/13/2016] [Indexed: 12/18/2022] Open
Abstract
In the mammalian central nervous system, reactive oxygen species (ROS) generation is counterbalanced by antioxidant defenses. When large amounts of ROS accumulate, antioxidant mechanisms become overwhelmed and oxidative cellular stress may occur. Therefore, ROS are typically characterized as toxic molecules, oxidizing membrane lipids, changing the conformation of proteins, damaging nucleic acids, and causing deficits in synaptic plasticity. High ROS concentrations are associated with a decline in cognitive functions, as observed in some neurodegenerative disorders and age-dependent decay of neuroplasticity. Nevertheless, controlled ROS production provides the optimal redox state for the activation of transductional pathways involved in synaptic changes. Since ROS may regulate neuronal activity and elicit negative effects at the same time, the distinction between beneficial and deleterious consequences is unclear. In this regard, this review assesses current research and describes the main sources of ROS in neurons, specifying their involvement in synaptic plasticity and distinguishing between physiological and pathological processes implicated.
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Affiliation(s)
- Thiago Fernando Beckhauser
- Physiology and Biophysics Department, Biomedical Sciences Institute, Sao Paulo University (USP), Butanta, Sao Paulo, Brazil
| | - José Francis-Oliveira
- Physiology and Biophysics Department, Biomedical Sciences Institute, Sao Paulo University (USP), Butanta, Sao Paulo, Brazil
| | - Roberto De Pasquale
- Physiology and Biophysics Department, Biomedical Sciences Institute, Sao Paulo University (USP), Butanta, Sao Paulo, Brazil
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15
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Mlejnek P, Dolezel P. Loss of mitochondrial transmembrane potential and glutathione depletion are not sufficient to account for induction of apoptosis by carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone in human leukemia K562 cells. Chem Biol Interact 2015; 239:100-10. [DOI: 10.1016/j.cbi.2015.06.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 06/07/2015] [Accepted: 06/22/2015] [Indexed: 12/20/2022]
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16
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Kim SY, Mammen A, Yoo SJ, Cho B, Kim EK, Park JI, Moon C, Ronnett GV. Phosphoinositide and Erk signaling pathways mediate activity-driven rodent olfactory sensory neuronal survival and stress mitigation. J Neurochem 2015; 134:486-98. [PMID: 25903517 DOI: 10.1111/jnc.13131] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 03/31/2015] [Accepted: 04/19/2015] [Indexed: 01/31/2023]
Abstract
Olfactory sensory neurons (OSNs) are the initial site for olfactory signal transduction. Therefore, their survival is essential to olfactory function. In the current study, we demonstrated that while odorant stimulation promoted rodent OSN survival, it induced generation of reactive oxygen species in a dose- and time-dependent manner as well as loss of membrane potential and fragmentation of mitochondria. The MEK-Erk pathway played a critical role in mediating these events, as its inhibition decreased odorant stimulation-dependent OSN survival and exacerbated intracellular stress measured by reactive oxygen species generation and heat-shock protein 70 expression. The phosphoinositide pathway, rather than the cyclic AMP pathway, mediated the odorant-induced activation of the MEK-Erk pathway. These findings provide important insights into the mechanisms of activity-driven OSN survival, the role of the phosphoinositide pathway in odorant signaling, and demonstrate that odorant detection and odorant stimulation-mediated survival proceed via independent signaling pathways. This mechanism, which permits independent regulation of odorant detection from survival signaling, may be advantageous if not diminished by repeated or prolonged odor exposure. We investigated the role of odorant stimulation in generating cellular stress and the molecular mechanisms mitigating such stress and promoting neuronal survival. Odorant stimulation promoted olfactory sensory neuron (OSN) survival and also induced intracellular oxidative stress, which was exacerbated when MEK/Erks pathway was inhibited. Sensory stimulation simultaneously activated at least two parallel pathways, the AC/cAMP cascade responsible for odorant detection, and phosphoinositide hydrolysis to promote odorant stimulation-dependent neuronal survival odorants may activate parallel signaling cascades to mediate sensory detection and sensory stimulation-dependent survival. AC, adenylyl cyclase; cAMP, cyclic adenosine monophosphate; Erk, extracellular signal-regulated kinase; MEK, MAPK/ERK kinase.
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Affiliation(s)
- So Yeun Kim
- Department of Brain & Cognitive Sciences, Graduate School, DaeguGyeungbuk Institute of Science and Technology, Daegu, Korea
| | - Alex Mammen
- Departments of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Seung-Jun Yoo
- Department of Brain & Cognitive Sciences, Graduate School, DaeguGyeungbuk Institute of Science and Technology, Daegu, Korea
| | - Bongki Cho
- Department of Brain & Cognitive Sciences, Graduate School, DaeguGyeungbuk Institute of Science and Technology, Daegu, Korea
| | - Eun-Kyoung Kim
- Department of Brain & Cognitive Sciences, Graduate School, DaeguGyeungbuk Institute of Science and Technology, Daegu, Korea
| | - Jong-In Park
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Cheil Moon
- Department of Brain & Cognitive Sciences, Graduate School, DaeguGyeungbuk Institute of Science and Technology, Daegu, Korea
| | - Gabriele V Ronnett
- Department of Brain & Cognitive Sciences, Graduate School, DaeguGyeungbuk Institute of Science and Technology, Daegu, Korea.,Departments of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Zander-Fox DL, Fullston T, McPherson NO, Sandeman L, Kang WX, Good SB, Spillane M, Lane M. Reduction of Mitochondrial Function by FCCP During Mouse Cleavage Stage Embryo Culture Reduces Birth Weight and Impairs the Metabolic Health of Offspring. Biol Reprod 2015; 92:124. [PMID: 25715796 DOI: 10.1095/biolreprod.114.123489] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 02/24/2015] [Indexed: 12/26/2022] Open
Abstract
The periconceptual environment represents a critical window for programming fetal growth trajectories and susceptibility to disease; however, the underlying mechanism responsible for programming remains elusive. This study demonstrates a causal link between reduction of precompaction embryonic mitochondrial function and perturbed offspring growth trajectories and subsequent metabolic dysfunction. Incubation of embryos with carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP), which uncouples mitochondrial oxidative phosphorylation, significantly reduced mitochondrial membrane potential and ATP production in 8-cell embryos and the number of inner cell mass cells within blastocysts; however, blastocyst development was unchanged. This perturbed embryonic mitochondrial function was concomitant with reduced birth weight in female offspring following embryo transfer, which persisted until weaning. FCCP-treated females also exhibited increased adiposity at 4 wk, increased adiposity gain between 4 and 14 wk, glucose intolerance at 8 wk, and insulin resistance at 14 wk. Although FCCP-treated males also exhibited reduced glucose tolerance, but their insulin sensitivity and adiposity gain between 4 and 14 wk was unchanged. To our knowledge, this is one of the first studies to demonstrate that reducing mitochondrial function and, thus, decreasing ATP output in the precompacting embryo can influence offspring phenotype. This is of great significance as a large proportion of patients requiring assisted reproductive technologies are of advanced maternal age or have a high body mass index, both of which have been independently linked with perturbed early embryonic mitochondrial function.
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Affiliation(s)
- Deirdre L Zander-Fox
- School of Paediatrics and Reproductive Health, University of Adelaide, South Australia, Australia Repromed, Dulwich, South Australia, Australia
| | - Tod Fullston
- School of Paediatrics and Reproductive Health, University of Adelaide, South Australia, Australia
| | - Nicole O McPherson
- School of Paediatrics and Reproductive Health, University of Adelaide, South Australia, Australia
| | - Lauren Sandeman
- School of Paediatrics and Reproductive Health, University of Adelaide, South Australia, Australia
| | - Wan Xian Kang
- School of Paediatrics and Reproductive Health, University of Adelaide, South Australia, Australia
| | - Suzanne B Good
- School of Paediatrics and Reproductive Health, University of Adelaide, South Australia, Australia
| | - Marni Spillane
- School of Paediatrics and Reproductive Health, University of Adelaide, South Australia, Australia
| | - Michelle Lane
- School of Paediatrics and Reproductive Health, University of Adelaide, South Australia, Australia Repromed, Dulwich, South Australia, Australia
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18
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Connolly NMC, Prehn JHM. The metabolic response to excitotoxicity - lessons from single-cell imaging. J Bioenerg Biomembr 2014; 47:75-88. [PMID: 25262286 DOI: 10.1007/s10863-014-9578-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 08/26/2014] [Indexed: 12/26/2022]
Abstract
Excitotoxicity is a pathological process implicated in neuronal death during ischaemia, traumatic brain injuries and neurodegenerative diseases. Excitotoxicity is caused by excess levels of glutamate and over-activation of NMDA or calcium-permeable AMPA receptors on neuronal membranes, leading to ionic influx, energetic stress and potential neuronal death. The metabolic response of neurons to excitotoxicity is complex and plays a key role in the ability of the neuron to adapt and recover from such an insult. Single-cell imaging is a powerful experimental technique that can be used to study the neuronal metabolic response to excitotoxicity in vitro and, increasingly, in vivo. Here, we review some of the knowledge of the neuronal metabolic response to excitotoxicity gained from in vitro single-cell imaging, including calcium and ATP dynamics and their effects on mitochondrial function, along with the contribution of glucose metabolism, oxidative stress and additional neuroprotective signalling mechanisms. Future work will combine knowledge gained from single-cell imaging with data from biochemical and computational techniques to garner holistic information about the metabolic response to excitotoxicity at the whole brain level and transfer this knowledge to a clinical setting.
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Affiliation(s)
- Niamh M C Connolly
- Department of Physiology and Medical Physics, 123 St Stephen's Green, Dublin 2, Ireland
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19
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Nicholls DG, Brand MD, Gerencser AA. Mitochondrial bioenergetics and neuronal survival modelled in primary neuronal culture and isolated nerve terminals. J Bioenerg Biomembr 2014; 47:63-74. [DOI: 10.1007/s10863-014-9573-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 08/20/2014] [Indexed: 12/20/2022]
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20
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Rotigotine protects against glutamate toxicity in primary dopaminergic cell culture. Eur J Pharmacol 2014; 724:31-42. [DOI: 10.1016/j.ejphar.2013.12.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 12/09/2013] [Accepted: 12/10/2013] [Indexed: 11/22/2022]
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21
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Weisová P, Anilkumar U, Ryan C, Concannon CG, Prehn JH, Ward MW. ‘Mild mitochondrial uncoupling’ induced protection against neuronal excitotoxicity requires AMPK activity. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:744-53. [DOI: 10.1016/j.bbabio.2012.01.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 01/30/2012] [Accepted: 01/31/2012] [Indexed: 11/25/2022]
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22
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Alekseenko AV, Lemeshchenko VV, Pekun TG, Waseem TV, Fedorovich SV. Glutamate-induced free radical formation in rat brain synaptosomes is not dependent on intrasynaptosomal mitochondria membrane potential. Neurosci Lett 2012; 513:238-42. [PMID: 22387155 DOI: 10.1016/j.neulet.2012.02.051] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 02/07/2012] [Accepted: 02/14/2012] [Indexed: 10/28/2022]
Abstract
Glutamate induces reactive oxygen species formation (ROS) in neurons. Free radicals can potentially be synthesized by NADPH oxidase or mitochondria. The primary source of ROS origin has yet to be identified. In addition, pro-oxidant action of glutamate receptors on neuronal presynaptic terminals is still not characterized. We investigated the influence of glutamate and agonists of its ionotropic receptors on ROS formation detected by fluorescent dye DCFDA in rat brain synaptosomes. Glutamate in concentration 10 and 100μM led to an increase of probe fluorescence pointing to free radical accumulation. This effect was mimicked by 100μM of NMDA or 100μM of kainate. Glutamate-induced ROS formation was sensitive to NMDA inhibitors MK-801 (10μM), NO synthase (NOS) inhibitor l-NAME (100μM) and NADPH oxidase inhibitors DPI (30μM) and not affected by mitochondrial uncoupler CCCP (10μM) and mitochondrial toxins rotenone (10μM)+oligomycin (5μg/ml). We also showed that 100μM of glutamate leads to a decrease of intrasynaptosomal mitochondrial potential monitored by fluorescent dye Rhodamine-123. Hence, the depolarization of intrasynaptosomal mitochondria is not a primary cause of glutamate-induced ROS formation in neuronal presynaptic terminals. Activation of NMDA receptors might be responsible for a certain part of glutamate pro-oxidant action. Most likely, sources of glutamate-induced ROS formation in neuronal presynaptic terminals are NADPH oxidase and NOS activation.
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Affiliation(s)
- Aleksandra V Alekseenko
- Laboratory of Biophysics and Engineering of Cell, Institute of Biophysics and Cell Engineering, Akademicheskaya St., 27, Minsk 220072, Belarus
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23
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Yang JL, Sykora P, Wilson DM, Mattson MP, Bohr VA. The excitatory neurotransmitter glutamate stimulates DNA repair to increase neuronal resiliency. Mech Ageing Dev 2011; 132:405-11. [PMID: 21729715 DOI: 10.1016/j.mad.2011.06.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Revised: 05/27/2011] [Accepted: 06/20/2011] [Indexed: 10/18/2022]
Abstract
Glutamate is the most abundant excitatory neurotransmitter in the vertebrate central nervous system and plays an important role in synaptic plasticity required for learning and memory. Activation of glutamate ionotropic receptors promptly triggers membrane depolarization and Ca(2+) influx, resulting in the activation of several different protein kinases and transcription factors. For example, glutamate-mediated Ca(2+) influx activates Ca(2+)/calmodulin-dependent kinase, protein kinase C, and mitogen activated protein kinases resulting in activation of transcription factors such as cyclic AMP response element binding protein (CREB). Abnormally prolonged exposure to glutamate causes neuronal injury, and such "excitotoxicity" has been implicated in many acute and chronic diseases including ischemic stroke, epilepsy, amyotrophic lateral sclerosis, Alzheimer's, Huntington's and Parkinson's diseases. Interestingly, although glutamate-induced Ca(2+) influx can cause DNA damage by a mitochondrial reactive oxygen species-mediated mechanism, the Ca(2+) simultaneously activates CREB, resulting in up-regulation of the DNA repair and redox protein apurinic/apyrimidinic endonuclease 1. Here, we review connections between physiological or aberrant glutamate receptor activation, Ca(2+)-mediated signaling, oxidative DNA damage and repair efficiency, and neuronal vulnerability. We conclude that glutamate signaling involves an adaptive cellular stress response pathway that enhances DNA repair capability, thereby protecting neurons against injury and disease.
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Affiliation(s)
- Jenq-Lin Yang
- Laboratory of Molecular Gerontology, National Institute on Aging Intramural Research Program, Baltimore, MD, USA.
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24
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Tretter L, Biagioni Angeli E, Ardestani MR, Goracci G, Adam-Vizi V. Reversible inhibition of hydrogen peroxide elimination by calcium in brain mitochondria. J Neurosci Res 2011; 89:1965-72. [PMID: 21541982 DOI: 10.1002/jnr.22658] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 03/03/2011] [Accepted: 03/14/2011] [Indexed: 11/07/2022]
Abstract
In the present work, the Ca(2+) dependence of mitochondrial H(2) O(2) elimination was investigated. Mitochondria isolated from guinea pig brain were energized by glutamate and malate and incubated with micromolar concentrations of Ca(2+) in the presence of ADP, preventing permeability transition pore formation. After the completion of Ca(2+) uptake, mitochondria were challenged with H(2) O(2) (5 μM), then at various time points residual H(2) O(2) was determined using the Amplex red method and compared with that in mitochondria incubated with H(2) O(2) without Ca(2+) addition. Dose-dependent inhibition of H(2) O(2) elimination by Ca(2+) was detected, which was prevented by the Ca(2+) -uptake inhibitor Ru 360. Stimulation of Ca(2+) release from Ca(2+) -loaded mitochondria by a combined addition of Ru 360 and Na(+) decreased the Ca(2+) -evoked inhibition of H(2) O(2) removal. After Ca(2+) uptake (50 μM), mitochondrial aconitase activity was found to be decreased, which was partially attributable to the impaired elimination of endogenously produced reactive oxygen species. We found that the effects of Ca(2+) and H(2) O(2) on the activity of aconitase were additive. These results confirm that Ca(2+) inhibits elimination of H(2) O(2) in mitochondria and demonstrate that this effect is concentration dependent and reversible. The phenomenon described here can play a role in the modulation of ROS handling under conditions involving excessive cellular Ca(2+) load.
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Affiliation(s)
- Laszlo Tretter
- Department of Medical Biochemistry, Semmelweis University, and Laboratory of Neurobiochemistry and Molecular Physiology, Hungarian Academy of Sciences, Budapest, Hungary
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25
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Selakovic V, Korenic A, Radenovic L. Spatial and temporal patterns of oxidative stress in the brain of gerbils submitted to different duration of global cerebral ischemia. Int J Dev Neurosci 2011; 29:645-54. [PMID: 21382467 DOI: 10.1016/j.ijdevneu.2011.02.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 02/01/2011] [Accepted: 02/25/2011] [Indexed: 10/18/2022] Open
Abstract
The present study was undertaken to examine spatial and temporal patterns of oxidative stress rate in the brain of Mongolian gerbils submitted to different duration of global ischemia/reperfusion. The common carotid arteries of gerbils were occluded for 5, 10, or 15 min. We followed the temporal ischemia-induced oxidative stress rate, the most important factor that exacerbates brain damage by reperfusion, starting from 24 h up to 28 days after reperfusion. The spatial ischemia-induced oxidative stress distribution was measured parallely in different brain regions: forebrain cortex, striatum, hippocampus and cerebellum. Post-ischemic effects were followed in vivo by monitoring the neurological status of whole animals and at the intracellular level by standard biochemical assays in different brain regions. We measured superoxide production, superoxide dismutase activity, nitric oxide production, index of lipid peroxidation, and reduced glutathione. Our results revealed a pattern of dynamic changes in each oxidative stress parameter that corresponded with ischemia duration in all tested brain structures. The highest levels were obtained in the first 24h after the insult. After that, they slowly returned to nearly control values 28 days after reperfusion (with the exception of SOD activity that returned to control values at fourth day after reperfusion). The most sensitive oxidative stress parameter was index of lipid peroxidation. Our study confirmed spatial distribution of ischemia-induced oxidative stress. Tested brain structures showed different sensitivity to each oxidative stress parameter, although their basal levels were similar. These new findings could be valuable for creation and strategy of post-ischemic therapy.
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26
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White MG, Wang Y, Akay C, Lindl KA, Kolson DL, Jordan-Sciutto KL. Parallel high throughput neuronal toxicity assays demonstrate uncoupling between loss of mitochondrial membrane potential and neuronal damage in a model of HIV-induced neurodegeneration. Neurosci Res 2011; 70:220-9. [PMID: 21291924 DOI: 10.1016/j.neures.2011.01.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 12/08/2010] [Accepted: 01/25/2011] [Indexed: 11/24/2022]
Abstract
Neurocognitive deficits seen in HIV-associated neurocognitive disorders (HANDs) are attributed to the release of soluble factors from CNS-resident, HIV-infected and/or activated macrophages and microglia. To study HIV-associated neurotoxicity, we used our in vitro model in which primary rat neuronal/glial cultures are treated with supernatants from cultured human monocyte-derived macrophages, infected with a CNS-isolated HIV-1 strain (HIV-MDM). We found that neuronal damage, detected as a loss of microtubule-associated protein-2 (MAP2), begins as early as 2h and is preceded by a loss of mitochondrial membrane potential (Δψ(m)). Interestingly, inhibitors of calpains, but not inhibitors of caspases, blocked MAP2 loss, however neither type of inhibitor prevented the loss of Δψ(m). To facilitate throughput for these studies, we refined a MAP2 cell-based-ELISA whose data closely compare with our standardized method of hand counting neurons. In addition, we developed a tetramethyl rhodamine methyl ester (TMRM)-based multi-well fluorescent plate assay for the evaluation of whole culture Δψ(m). Together, these findings indicate that calpain activation and loss of Δψ(m) may be parallel pathways to death in HIV-MDM-treated neurons and also demonstrate the validity of plate assays for assessing multiple experimental parameters as is useful for screening neurotherapeutics for neuronal damage and death.
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Affiliation(s)
- Michael G White
- Department of Pathology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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27
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Isaev NK, Stelmashook EV, Dirnagl U, Plotnikov EY, Kuvshinova EA, Zorov DB. Mitochondrial free radical production induced by glucose deprivation in cerebellar granule neurons. BIOCHEMISTRY (MOSCOW) 2011; 73:149-55. [DOI: 10.1134/s0006297908020053] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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28
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Yang JL, Tadokoro T, Keijzers G, Mattson MP, Bohr VA. Neurons efficiently repair glutamate-induced oxidative DNA damage by a process involving CREB-mediated up-regulation of apurinic endonuclease 1. J Biol Chem 2010; 285:28191-9. [PMID: 20573957 PMCID: PMC2934684 DOI: 10.1074/jbc.m109.082883] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 06/03/2010] [Indexed: 11/06/2022] Open
Abstract
Glutamate, the major excitatory neurotransmitter in the brain, activates receptors coupled to membrane depolarization and Ca(2+) influx that mediates functional responses of neurons including processes such as learning and memory. Here we show that reversible nuclear oxidative DNA damage occurs in cerebral cortical neurons in response to transient glutamate receptor activation using non-toxic physiological levels of glutamate. This DNA damage was prevented by intracellular Ca(2+) chelation, the mitochondrial superoxide dismutase mimetic MnTMPyP (Mn-5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine chloride tetrakis(methochloride)), and blockade of the permeability transition pore. The repair of glutamate-induced DNA damage was associated with increased DNA repair activity and increased mRNA and protein levels of apurinic endonuclease 1 (APE1). APE1 knockdown induced accumulation of oxidative DNA damage after glutamate treatment, suggesting that APE1 is a key repair protein for glutamate-induced DNA damage. A cAMP-response element-binding protein (CREB) binding sequence is present in the Ape1 gene (encodes APE1 protein) promoter and treatment of neurons with a Ca(2+)/calmodulin-dependent kinase inhibitor (KN-93) blocked the ability of glutamate to induce CREB phosphorylation and APE1 expression. Selective depletion of CREB using RNA interference prevented glutamate-induced up-regulation of APE1. Thus, glutamate receptor stimulation triggers Ca(2+)- and mitochondrial reactive oxygen species-mediated DNA damage that is then rapidly repaired by a mechanism involving Ca(2+)-induced, CREB-mediated APE1 expression. Our findings reveal a previously unknown ability of neurons to efficiently repair oxidative DNA lesions after transient activation of glutamate receptors.
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Affiliation(s)
- Jenq-Lin Yang
- From the Laboratories of Molecular Gerontology and
- Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland 21224
| | | | | | - Mark P. Mattson
- Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, Maryland 21224
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Selakovic V, Janac B, Radenovic L. MK-801 effect on regional cerebral oxidative stress rate induced by different duration of global ischemia in gerbils. Mol Cell Biochem 2010; 342:35-50. [PMID: 20422259 DOI: 10.1007/s11010-010-0466-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 04/12/2010] [Indexed: 12/19/2022]
Abstract
We investigated MK-801 effect on ischemia-induced oxidative stress-the most important factor that exacerbates brain damage by reperfusion. The common carotid arteries of gerbils were occluded for 5, 10, or 15 min. Immediately after the occlusion, MK-801 (3 mg/kg i.p.) or saline were given in normothermic conditions. The MK-801 effects were followed in vivo by monitoring the neurological status of animals and at the intracellular level by standard biochemical assays. We investigated nitric oxide levels, superoxide production, superoxide dismutase activity, index of lipid peroxidation (ILP), and reduced glutathione content in hippocampus, striatum, forebrain cortex, and cerebellum. The measurements took place at different times (1, 2, 4, 7, 14, and 28 days) after reperfusion. Increased duration of cerebral ischemia resulted in a progressive induction of oxidative stress. Our results revealed pattern of dynamic changes in each oxidative stress parameter level which corresponded with ischemia duration in all tested brain structures. Most sensitive oxidative stress parameters were ILP and superoxide production. Our study confirmed spatial distribution of ischemia-induced oxidative stress. Tested brain structures showed different sensitivity to each oxidative stress parameter. As judged by biochemical and neurological data, applied MK-801 showed neuroprotective efficiency by reduction of ischemia-induced oxidative stress in brain.
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Overexpression of Aldehyde Dehydrogenase-2 Attenuates Neurotoxicity Induced by 4-Hydroxynonenal in Cultured Primary Hippocampal Neurons. Neurotox Res 2010; 19:412-22. [DOI: 10.1007/s12640-010-9183-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 01/24/2010] [Accepted: 03/24/2010] [Indexed: 12/30/2022]
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Komary Z, Tretter L, Adam-Vizi V. Membrane potential-related effect of calcium on reactive oxygen species generation in isolated brain mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:922-8. [PMID: 20230776 DOI: 10.1016/j.bbabio.2010.03.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 03/04/2010] [Accepted: 03/06/2010] [Indexed: 01/29/2023]
Abstract
The effect of Ca2+ applied in high concentrations (50 and 300 microM) was addressed on the generation of reactive oxygen species in isolated mitochondria from guinea-pig brain. The experiments were performed in the presence of ADP, a very effective inhibitor of mitochondrial permeability transition. Moderate increase in H2O2 release from mitochondria was induced by Ca2+ applied in 50 microM, but not in 300 microM concentration as measured with Amplex red fluorescent assay starting with a delay of 100-150 sec after exposure to Ca2+. Parallel measurements of membrane potential (DeltaPsim) by safranine fluorescence showed a transient depolarization by Ca2+ followed by the recovery of DeltaPsim to a value, which was more negative than that observed before addition of Ca2+ indicating a relative hyperpolarization. NAD(P)H fluorescence was also increased by Ca2+ given in 50 microM concentration. In mitochondria having high DeltaPsim in the presence of oligomycin or ATP, the basal rate of release of H2O2 was significantly higher than that observed in a medium containing ADP and Ca2+ no longer increased but rather decreased the rate of H2O2 release. With 300 microM Ca2+ only a loss but no tendency of a recovery of DeltaPsim was detected and H2O2 release was unchanged. It is suggested that in the presence of nucleotides the effect of Ca2+ on mitochondrial ROS release is related to changes in DeltaPsim; in depolarized mitochondria, in the presence of ADP, moderate increase in H2O2 release is induced by calcium, but only in <or=100 microM concentration, when after a transient Ca2+-induced depolarization mitochondria became more polarized. In highly polarized mitochondria, in the presence of ATP or oligomycin, where no hyperpolarization follows the Ca2+-induced depolarization, Ca2+ fails to stimulate mitochondrial ROS generation. These effects of calcium (<or=300 microM) are unrelated to mitochondrial permeability transition.
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Affiliation(s)
- Zsofia Komary
- Department of Medical Biochemistry, Semmelweis University, Neurobiochemical Group, Hungarian Academy of Sciences, Hungary
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Lipid peroxidation and antioxidant protection in patients during acute depressive episodes and in remission after fluoxetine treatment. Pharmacol Rep 2009; 61:436-47. [PMID: 19605942 DOI: 10.1016/s1734-1140(09)70084-2] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Revised: 04/21/2009] [Indexed: 12/21/2022]
Abstract
Increasing numbers of studies indicate that free radicals and their derivatives play a role in some neuropsychiatric disorders, such as depression. The aim of this study was to investigate the activities of antioxidant enzymes, lipid peroxidation and total antioxidant status (TAS) in patients suffering from major depressive disorder (MDD) as compared to healthy controls. Specifically, we wanted to estimate how fluoxetine influences antioxidant defense and lipid peroxidation. Fifty MDD patients and thirty healthy controls participated in the study. Antioxidant enzyme activities and lipid peroxidation levels were measured in erythrocytes, while TAS was measured in plasma. All measurements were taken during an acute depressive episode and then again during depression remission after a three-month fluoxetine treatment. During acute depressive episodes, patients had significantly higher activity levels of antioxidant enzymes, such as copper-zinc superoxide dismutase (SOD1) and catalase (CAT), as compared to healthy controls. Concentrations of malondialdehyde (MDA) were also significantly higher during depressive episodes. Activity levels of glutathione peroxidase (GPx) did not differ significantly between depressed patients and healthy control subjects. Moreover, the plasma total antioxidant status of the depressed patients was decreased in comparison to control subjects. After three months of fluoxetine treatment, the above parameters did not change significantly. Major depressive disorder is accompanied by disturbances in the balance between pro- and anti-oxidative processes; however, these disturbances do not improve in patients in remission after three months of fluoxetine therapy.
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Gałecki P, Szemraj J, Bieńkiewicz M, Zboralski K, Gałecka E. Oxidative stress parameters after combined fluoxetine and acetylsalicylic acid therapy in depressive patients. Hum Psychopharmacol 2009; 24:277-86. [PMID: 19319921 DOI: 10.1002/hup.1014] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
OBJECTIVE There are numerous reports indicating disturbed equilibrium between oxidative processes and antioxidative defense in patients with depression. Moreover, depressive patients are characterized by the presence of elements of an inflammatory process, which is one of the sources of reactive oxygen species (ROS). In view of the above, it was decided to study both the effect of fluoxetine monotherapy and that of fluoxetine co-administered with acetylsalicylic acid on lipid peroxidation and antioxidative defense in patients with the first depressive episode in their life. METHOD Seventy seven patients with major depressive disorder (MDD), divided into two groups were included in the study. The first group, consisting of 52 patients, received fluoxetine 20 mg, and the second one, in addition to fluoxetine 20 mg, received 150 mg of acetylsalicylic acid. The activity of antioxidative enzymes, copper-zinc superoxide dismutase (CuZnSOD, SOD1), catalase (CAT), glutathione peroxidase (GPSH-x) and the concentration of malonyldialdehyde (MDA) was determined in erythrocytes, whereas the total antioxidant status (TAS) was determined in the plasma. All parameters were measured before and after three month therapy. RESULTS The obtained results indicate a significant decrease in the activity of SOD1, CAT and GSHP-x, as well as in MDA concentration after the combined therapy. Also a significant TAS increase was observed after the combined therapy. The study demonstrated that combined therapy with fluoxetine and ASA is characterized by the same efficacy and clinical safety as fluoxetine monotherapy, resulting additionally in improvement of oxidative stress parameters in the patients treated for depression.
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Affiliation(s)
- Piotr Gałecki
- Department of Adult Psychiatry, Medical University of Lodz, Lodz, Poland.
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Patel SP, Sullivan PG, Pandya JD, Rabchevsky AG. Differential effects of the mitochondrial uncoupling agent, 2,4-dinitrophenol, or the nitroxide antioxidant, Tempol, on synaptic or nonsynaptic mitochondria after spinal cord injury. J Neurosci Res 2009; 87:130-140. [PMID: 18709657 DOI: 10.1002/jnr.21814] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We recently documented the progressive nature of mitochondrial dysfunction over 24 hr after contusion spinal cord injury (SCI), but the underlying mechanism has not been elucidated. We investigated the effects of targeting two distinct possible mechanisms of mitochondrial dysfunction by using the mitochondrial uncoupler 2,4-dinitrophenol (2,4-DNP) or the nitroxide antioxidant Tempol after contusion SCI in rats. A novel aspect of this study was that all assessments were made in both synaptosomal (neuronal)- and nonsynaptosomal (glial and neuronal soma)-derived mitochondria 24 hr after injury. Mitochondrial uncouplers target Ca(2+) cycling and subsequent reactive oxygen species production in mitochondria after injury. When 2,4-DNP was injected 15 and 30 min after injury, mitochondrial function was preserved in both populations compared with vehicle-treated rats, whereas 1 hr postinjury treatment was ineffective. Conversely, targeting peroxynitrite with Tempol failed to maintain normal bioenergetics in synaptic mitochondria, but was effective in nonsynaptic mitochondria when administered 15 min after injury. When administered at 15 and 30 min after injury, increased hydroxynonenal, 3-NT, and protein carbonyl levels were significantly reduced by 2,4-DNP, whereas Tempol only reduced 3-NT and protein carbonyls after SCI. Despite such antioxidant effects, only 2,4-DNP was effective in preventing mitochondrial dysfunction, indicating that mitochondrial Ca(2+) overload may be the key mechanism involved in acute mitochondrial damage after SCI. Collectively, our observations demonstrate the significant role that mitochondrial dysfunction plays in SCI neuropathology. Moreover, they indicate that combinatorial therapeutic approaches targeting different populations of mitochondria holds great potential in fostering neuroprotection after acute SCI.
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Affiliation(s)
- Samir P Patel
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington.,Department of Physiology, University of Kentucky, Lexington
| | - Patrick G Sullivan
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington.,Department of Anatomy and Neurobiology, University of Kentucky, Lexington
| | - Jignesh D Pandya
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington.,Department of Anatomy and Neurobiology, University of Kentucky, Lexington
| | - Alexander G Rabchevsky
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington.,Department of Physiology, University of Kentucky, Lexington
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Temporal patterns of motor behavioural improvements by MK-801 in Mongolian gerbils submitted to different duration of global cerebral ischemia. Behav Brain Res 2008; 194:72-8. [DOI: 10.1016/j.bbr.2008.06.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 06/17/2008] [Accepted: 06/20/2008] [Indexed: 01/09/2023]
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Kim HY, Chung JM, Chung K. Increased production of mitochondrial superoxide in the spinal cord induces pain behaviors in mice: the effect of mitochondrial electron transport complex inhibitors. Neurosci Lett 2008; 447:87-91. [PMID: 18832013 DOI: 10.1016/j.neulet.2008.09.041] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 08/22/2008] [Accepted: 09/13/2008] [Indexed: 10/21/2022]
Abstract
Scavengers of reactive oxygen species (ROS) have been shown to produce a strong antinociceptive effect on persistent pain, and mitochondria are suggested to be the main source of ROS in the spinal dorsal horn. To explore whether excessive generation of mitochondrial superoxide alone can induce pain, the effect of mitochondrial electron transport complex inhibitors on the development of mechanical hyperalgesia was examined in mice. Intrathecal injection of an electron transport complex inhibitor, antimycin A or rotenone, in normal mice resulted in a slowly developing but long-lasting and dose-dependent mechanical hyperalgesia. The levels of mechanical hyperalgesia after antimycin A, a complex III inhibitor, were higher than that with rotenone, a complex I inhibitor. A large increase of mitochondrial superoxide in the spinal dorsal horn and a strong antinociceptive effect of ROS scavengers, phenyl-N-tert-butylnitrone (PBN) and 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPOL) were observed in antimycin A-treated mice. The study indicates that the enhanced production of spinal mitochondrial superoxide alone without nerve injury can produce mechanical hyperalgesia.
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Affiliation(s)
- Hee Young Kim
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-1069, USA
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37
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Hansson MJ, Månsson R, Morota S, Uchino H, Kallur T, Sumi T, Ishii N, Shimazu M, Keep MF, Jegorov A, Elmér E. Calcium-induced generation of reactive oxygen species in brain mitochondria is mediated by permeability transition. Free Radic Biol Med 2008; 45:284-94. [PMID: 18466779 DOI: 10.1016/j.freeradbiomed.2008.04.021] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Revised: 03/30/2008] [Accepted: 04/05/2008] [Indexed: 11/30/2022]
Abstract
Mitochondrial uptake of calcium in excitotoxicity is associated with subsequent increase in reactive oxygen species (ROS) generation and delayed cellular calcium deregulation in ischemic and neurodegenerative insults. The mechanisms linking mitochondrial calcium uptake and ROS production remain unknown but activation of the mitochondrial permeability transition (mPT) may be one such mechanism. In the present study, calcium increased ROS generation in isolated rodent brain and human liver mitochondria undergoing mPT despite an associated loss of membrane potential, NADH and respiration. Unspecific permeabilization of the inner mitochondrial membrane by alamethicin likewise increased ROS independently of calcium, and the ROS increase was further potentiated if NAD(H) was added to the system. Importantly, calcium per se did not induce a ROS increase unless mPT was triggered. Twenty-one cyclosporin A analogs were evaluated for inhibition of calcium-induced ROS and their efficacy clearly paralleled their potency of inhibiting mPT-mediated mitochondrial swelling. We conclude that while intact respiring mitochondria possess powerful antioxidant capability, mPT induces a dysregulated oxidative state with loss of GSH- and NADPH-dependent ROS detoxification. We propose that mPT is a significant cause of pathological ROS generation in excitotoxic cell death.
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Affiliation(s)
- Magnus J Hansson
- Department of Clinical Sciences, Lund University, SE-221 84 Lund, Sweden.
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Ali SS, Hardt JI, Dugan LL. SOD activity of carboxyfullerenes predicts their neuroprotective efficacy: a structure-activity study. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2008; 4:283-94. [PMID: 18656425 DOI: 10.1016/j.nano.2008.05.003] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 04/29/2008] [Accepted: 05/09/2008] [Indexed: 01/26/2023]
Abstract
Superoxide radical anion is a biologically important oxidant that has been linked to tissue injury and inflammation in several diseases. Here we carried out a structure-activity study on six different carboxyfullerene superoxide dismutase (SOD) mimetics with distinct electronic and biophysical characteristics. Neurotoxicity via N-methyl-D-aspartate receptors, which involves intracellular superoxide, was used as a model to evaluate structure-activity relationships between reactivity toward superoxide and neuronal rescue by these drugs. A significant correlation between neuroprotection by carboxyfullerenes and their ki toward superoxide radical was observed. Computer-assisted molecular modeling demonstrated that the reactivity toward superoxide is sensitive to changes in dipole moment, which are dictated not only by the number of carboxyl groups but also by their distribution on the fullerene ball. These results indicate that the SOD activity of these cell-permeable compounds predicts neuroprotection, and establishes a structure-activity relationship to aid in future studies on the biology of superoxide across disciplines.
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Affiliation(s)
- Sameh Saad Ali
- Department of Medicine, University of California, San Diego, California, USA.
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Neuroprotective effects of memantine in a mouse model of retinal degeneration induced by rotenone. Brain Res 2008; 1215:208-17. [PMID: 18486118 DOI: 10.1016/j.brainres.2008.04.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 04/02/2008] [Accepted: 04/02/2008] [Indexed: 11/24/2022]
Abstract
This is the first report of the in vivo effectiveness of memantine as a neuroprotective agent against rotenone-induced retinal toxicity. We tested the hypothesis that uncompetitive NMDAR blockade with memantine prevents mitochondrial dysfunction-related neurodegeneration in vivo, using a mouse model of retinal ganglion cell layer (GCL) degeneration induced by rotenone, a mitochondrial complex I inhibitor. Rotenone induced an increase in cell death and oxidative stress in GCL compared to controls, and these changes were prevented by the co-administration of memantine. The neurotoxic effect of rotenone was also reflected as a decrease in total cell density in GCL and GCL+nerve fiber layer thickness. These changes were also prevented by co-administration of memantine in a dose-dependent manner. In addition, memantine induced an increase in long-term retinal energy metabolic capacity. The results suggest that NMDAR activation contributes to cell death induced by mitochondrial dysfunction and that uncompetitive NMDAR blockade may be used as a neuroprotective strategy against mitochondrial dysfunction in neurodegenerative diseases.
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Fekete A, Vizi ES, Kovács KJ, Lendvai B, Zelles T. Layer-specific differences in reactive oxygen species levels after oxygen-glucose deprivation in acute hippocampal slices. Free Radic Biol Med 2008; 44:1010-22. [PMID: 18206124 DOI: 10.1016/j.freeradbiomed.2007.11.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 09/19/2007] [Accepted: 11/25/2007] [Indexed: 11/15/2022]
Abstract
The major role of reactive oxygen species (ROS) in the pathomechanism of ischemia have been widely recognized. Still, measurements of the precise time course and regional distribution of ischemia-induced ROS level changes in acute brain slices have been missing. By using acute hippocampal slices and the fluorescent dye CM-H2DCFDA, we showed that reoxygenation after in vitro ischemia (oxygen-glucose deprivation; OGD) increased ROS levels in the hippocampal CA1 layers vulnerable to ischemia but did not have significant effects in the resistant stratum granulosum in the dentate gyrus (DG). Production of ROS started during OGD, but, contrary to reoxygenation, it manifested as a ROS level increase exclusively in the presence of catalase and glutathione peroxidase inhibition. The mechanism of ROS production involves the activation of NMDA receptors and nitric oxide synthases. The inhibition of ROS response by either AP-5 or L-NAME together with the ROS sensitivity profile of the dye suggest that peroxynitrite, the reaction product of superoxide and nitric oxide, plays a role in the response. Direct visualization of layer-specific effects of ROS production and its scavenging, shown for the first time in acute hippocampal slices, suggests that distinct ROS homeostasis may underlie the different ischemic vulnerability of CA1 and DG.
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Affiliation(s)
- Adám Fekete
- Laboratory of Cellular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, 1083 Budapest, Szigony u. 43., Hungary
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Use of confocal microscopy in the study of ischemia-induced hippocampal neuronal damage. ARCH BIOL SCI 2008. [DOI: 10.2298/abs0804561r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The present study was undertaken to reveal by means of confocal laser microscopy the cytoarchitecture of hippocampal CA3 neurons in Mongolian gerbils before and after cerebral ischemia of different duration. The common carotid arteries of gerbils were occluded for 5, 10, or 15 min. On the 4th, 14th and 28th day after reperfusion, neuronal damage was examined by laser scanning confocal microscopy in the CA3 region of hippocampus (30 ?m slices). Slices were stained with fluorescent Nissl staining and fluorescent membrane tracer DiI. Increased duration of cerebral ischemia resulted in a progressive loss of hippocampal CA3 neurons. Four days after the ischemic insult, neuronal damage in the hippocampal CA3 region was mild but visible. On the 28th day after reperfusion, neuronal damage in the observed brain structure was most severe. These results demonstrate the temporal profile of neuronal damage after an ischemic insult as observed using confocal microscopy.
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Ebselen attenuates oxidative DNA damage and enhances its repair activity in the thalamus after focal cortical infarction in hypertensive rats. Brain Res 2007; 1181:83-92. [DOI: 10.1016/j.brainres.2007.08.072] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 08/17/2007] [Accepted: 08/25/2007] [Indexed: 12/20/2022]
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Xiong Y, Shie FS, Zhang J, Lee CP, Ho YS. The protective role of cellular glutathione peroxidase against trauma-induced mitochondrial dysfunction in the mouse brain. J Stroke Cerebrovasc Dis 2007; 13:129-37. [PMID: 17903964 DOI: 10.1016/j.jstrokecerebrovasdis.2004.05.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2004] [Revised: 04/04/2004] [Accepted: 04/25/2004] [Indexed: 12/27/2022] Open
Abstract
Reactive oxygen species are believed to participate in the pathogenesis of traumatic brain injury (TBI). To evaluate the role of cellular glutathione peroxidase (Gpx1), a selenium-containing enzyme functioning in reduction of hydrogen peroxide and alkyl hyperoxides, in protecting animals against TBI, a line of Gpx1 transgenic mice was generated. Overexpression of Gpx1 was found in many organs including the brain of the transgenic mice. This line of transgenic mice and knockout mice deficient in Gpx1 were used in a model of controlled cortical impact injury and the efficiency of oxidative phosphorylation in brain mitochondria was determined. Although a 2-mm depth of mechanical impact caused a drastic decrease in NAD-linked electron transfer activities and energy-coupling capacities in brain mitochondria of nontransgenic mice, the decrease in mitochondrial function was completely prevented by overexpression of Gpx1 in Gpx1 transgenic mice. In addition, a 1-mm deformation depth hardly affected brain mitochondrial function in wild-type (Gpx1+/+) mice, yet resulted in a significant decrease in mitochondrial bioenergetic capacity in brains of homozygous Gpx1 knockout (Gpx1-/-) mice. Further experiments showed that inclusion of calcium chelator egtazic acid in measurement of mitochondrial respiration could completely restore the efficiency of mitochondrial respiration in injured brains of nontransgenic mice and Gpx1-/- mice, suggesting that the observed mitochondrial dysfunction is a direct result of increase in mitochondrion-associated calcium, which is secondary to the increased oxidative stress. These studies not only establish the role of Gpx1 in preventing mitochondrial dysfunction in mouse brain after TBI, but also suggest the species of reactive oxygen responsible for this event.
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Affiliation(s)
- Ye Xiong
- Institute of Environmental Health Sciences, Wayne State University, Detroit, Michigan 48201, USA
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Palomba L, Amadori A, Cantoni O. Early release of arachidonic acid prevents an otherwise immediate formation of toxic levels of peroxynitrite in astrocytes stimulated with lipopolysaccharide/interferon-γ. J Neurochem 2007; 103:904-13. [PMID: 17666049 DOI: 10.1111/j.1471-4159.2007.04793.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Addition of bacterial lipopolysaccharides (LPS) and interferon-gamma (IFN-gamma) to rat astrocytes in primary culture promotes an early release of arachidonic acid (ARA) associated with an immediate inhibition of neuronal nitric oxide synthase (nNOS). Preventing the release of constitutive nitric oxide (NO) is indeed critical for activation of the nuclear factor kappa B, and for the expression of inducible nitric oxide synthase responsible for the formation of large amounts of NO. LPS/IFN-gamma also promotes an early release of superoxide, via activation of NADPH oxidase, but the generation of peroxynitrite (ONOO-) is prevented by the different timing of superoxide (minutes) and NO (hours) formation. Upstream inhibition of the ARA-dependent nNOS inhibitory signaling, however, caused the parallel release of superoxide and constitutive NO, thereby leading to formation of ONOO- levels triggering loss of ATP and mitochondrial membrane potential followed by the mitochondrial release of cytochrome c, activation of caspase 3 and morphological evidence of apoptosis. Nanomolar levels of exogenous ARA prevented all these events via inhibition of early ONOO- formation. Thus, the ARA-dependent nNOS inhibition observed in astrocytes exposed to pro-inflammatory stimuli, as LPS/IFN-gamma, is critical for both the expression of nuclear factor kappa B-dependent genes and for survival.
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Affiliation(s)
- Letizia Palomba
- Istituto di Farmacologia e Farmacognosia, Università di Urbino Carlo Bo, Urbino (PU) - Italy
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Barhwal K, Singh SB, Hota SK, Jayalakshmi K, Ilavazhagan G. Acetyl-l-Carnitine ameliorates hypobaric hypoxic impairment and spatial memory deficits in rats. Eur J Pharmacol 2007; 570:97-107. [PMID: 17610872 DOI: 10.1016/j.ejphar.2007.05.063] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 05/26/2007] [Accepted: 05/30/2007] [Indexed: 10/23/2022]
Abstract
Inadequate oxygen availability at high altitude causes oxidative stress and generation of reactive oxygen species, which may lead to memory impairment. Hippocampus, which plays a key role in the learning and memory processes, is especially vulnerable to hypoxic damage. The present study was aimed at investigating the effect of acetyl-L-carnitine on spatial working and reference memory deficits along with oxidative and apoptotic damage, caused by hypobaric hypoxia in male Sprague Dawley rats. Rats were trained in Morris Water Maze for eight days after which they were submitted to chronic hypobaric hypoxia exposure at a simulated altitude of 6100 m for three days. Rats received daily acetyl-L-carnitine at a dosage of 75 mg/kg body weight orally during exposure. Subsequent to exposure, performance of the animals was tested in Morris Water Maze, which revealed working memory impairment that was significantly improved by acetyl-L-carnitine. However, there was no change in the reference memory after hypobaric hypoxia exposure. Following behavioral study animals were sacrificed and biomarkers of oxidative damage like free radical production, lactate dehydrogenase activity, lipid peroxidation, antioxidant status and expression of apoptotic [viz. caspase-3, Apoptosis activating factor (Apaf-1), bax, cytochrome c] and anti-apoptotic protein-Bcl-2 were studied in the hippocampus. There was a significant increase in oxidative stress along with increased expression of apoptotic proteins and NR1 subunit of glutamate receptor indicating occurrence of excitotoxicity in hypoxia exposed rats. These results suggested that supplementation with acetyl-L-carnitine improves spatial working memory deficits reduces oxidative stress and inhibits apoptotic cascade induced by hypoxia.
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Affiliation(s)
- Kalpana Barhwal
- Defence Institute of Physiology and Allied Sciences, Defence Research and Development Organization, Lucknow Road, Timarpur, Delhi-110054, India
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D'Agostino DP, Putnam RW, Dean JB. Superoxide (·O2−) Production in CA1 Neurons of Rat Hippocampal Slices Exposed to Graded Levels of Oxygen. J Neurophysiol 2007; 98:1030-41. [PMID: 17553943 DOI: 10.1152/jn.01003.2006] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neuronal signaling, plasticity, and pathologies in CA1 hippocampal neurons are all intimately related to the redox environment and, thus tissue oxygenation. This study tests the hypothesis that hyperoxic superfusate (95% O2) causes a time-dependent increase in superoxide anion (·O2−) production in CA1 neurons in slices, which will decrease as oxygen concentration is decreased. Hippocampal slices (400 μm) from weaned rats were incubated with the fluorescent probe dihydroethidium (DHE), which detects intracellular ·O2− production. Slices were loaded for 30 min using 10 μM DHE and maintained using one-sided superfusion or continuously loaded using 2.5 μM DHE and maintained using two-sided superfusion (36°C). Continuous loading of DHE and two-sided superfusion gave the highest temporal resolution measurements of ·O2− production, which was estimated by the increase in fluorescence intensity units (FIUs) per minute (FIU/min ± SE) over 4 h. Superoxide production (2.5 μM DHE, 2-sided superfusion) was greatest in 95% O2 (6.6 ± 0.4 FIU/min) and decreased significantly during co-exposure with antioxidants (100 μM melatonin, 25 μM MnTMPyP) and lower levels of O2 (60, 40, and 20% O2 at 5.3 ± 0.3, 3.3 ± 0.1, and 1.6 ± 0.2 FIU/min, respectively). CA1 cell death after 4 h (ethidium homodimer-1 staining) was greatest in 95% O2 and lowest in 40 and 20% O2. CA1 neurons generated evoked action potentials in 20% O2 for >4 h, indicating viability at lower levels of oxygenation. We conclude that ·O2− production and cell death in CA1 neurons increases in response to increasing oxygen concentration product (= PO2 × time). Additionally, lower levels of oxygen (20–40%) and antioxidants should be considered to minimize superoxide-induced oxidative stress in brain slices.
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Affiliation(s)
- Dominic P D'Agostino
- Department of Molecular Pharmacology and Physiology, College of Medicine, University of South Florida, Tampa, Florida 33612, USA
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Pandya JD, Pauly JR, Nukala VN, Sebastian AH, Day KM, Korde AS, Maragos WF, Hall ED, Sullivan PG. Post-Injury Administration of Mitochondrial Uncouplers Increases Tissue Sparing and Improves Behavioral Outcome following Traumatic Brain Injury in Rodents. J Neurotrauma 2007; 24:798-811. [PMID: 17518535 DOI: 10.1089/neu.2006.3673] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Following experimental traumatic brain injury (TBI), a rapid and significant necrosis occurs at the site of injury which coincides with significant mitochondrial dysfunction. The present study is driven by the hypothesis that TBI-induced glutamate release increases mitochondrial Ca(2+)cycling/overload, ultimately leading to mitochondrial dysfunction. Based on this premise, mitochondrial uncoupling during the acute phases of TBI-induced excitotoxicity should reduce mitochondrial Ca(2+) uptake (cycling) and reactive oxygen species (ROS) production since both are mitochondrial membrane potential dependent. In the present study, we utilized a cortical impact model of TBI to assess the potential use of mitochondrial uncouplers (2,4-DNP, FCCP) as a neuroprotective therapy. Young adult male rats were intraperitoneally administered vehicle (DMSO), 2,4-DNP (5 mg/kg), or FCCP (2.5 mg/kg) at 5 min post-injury. All animals treated with the uncouplers demonstrated a significant reduction in the amount of cortical damage and behavioral improvement following TBI. In addition, mitochondria isolated from the injured cortex at 3 or 6 h post-injury demonstrated that treatment with the uncouplers significantly improved several parameters of mitochondrial bioenergetics. These results demonstrate that post-injury treatment with mitochondrial uncouplers significantly (p < 0.01) increases cortical tissue sparing ( approximately 12%) and significantly (p< 0.01) improves behavioral outcome following TBI. The mechanism of neuroprotection most likely involves the maintenance of mitochondrial homeostasis by reducing mitochondrial Ca(2+) loading and subsequent mitochondrial dysfunction. These results further implicate mitochondrial dysfunction as an early event in the pathophysiology of TBI and that targeting acute mitochondrial events can result in long-term neuroprotection and improve behavioral outcome following brain injury.
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Affiliation(s)
- Jignesh D Pandya
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536-0305, USA
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Akarsu S, Yilmaz S, Ozan S, Kurt A, Benzer F, Gurgoze MK. Effects of febrile and afebrile seizures on oxidant state in children. Pediatr Neurol 2007; 36:307-11. [PMID: 17509462 DOI: 10.1016/j.pediatrneurol.2007.01.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2006] [Revised: 11/28/2006] [Accepted: 01/15/2007] [Indexed: 11/26/2022]
Abstract
No comparative studies have addressed the oxidant and antioxidant states of blood and cerebrospinal fluid. To reveal this differential state, the study was designed to identify the seizure type with the worse prognosis by determining erythrocyte arginase and erythrocyte catalase, plasma and cerebrospinal fluid malondialdehyde, and plasma and cerebrospinal fluid nitric oxide levels. Study groups were classified as febrile (group 1, n = 21), afebrile (group 2, n = 21), and control (group 3, n = 41, subdivided as 3a, febris positive, convulsion negative, and 3b, febris negative, convulsion negative). Levels of erythrocyte arginase, erythrocyte catalase, plasma malondialdehyde, cerebrospinal fluid malondialdehyde, plasma nitric oxide, and cerebrospinal fluid nitric oxide levels were determined for all groups. A difference was detected between the control and febrile seizure groups with respect to erythrocyte catalase and plasma and cerebrospinal fluid levels of nitric oxide (P < 0.05). Both febrile states and convulsions influence oxidative mechanism. Oxidative stress-generating potential differs for febrile and afebrile seizures. In afebrile seizures, greater levels of oxidative stress might affect prognosis adversely. This phenomenon can be interpreted in terms of fever as a protective factor against possible neurological damage during convulsive seizures.
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Affiliation(s)
- Saadet Akarsu
- Department of Pediatrics, Faculty of Medicine, Firat University, Elazig, Turkey.
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Johnson-Cadwell LI, Jekabsons MB, Wang A, Polster BM, Nicholls DG. 'Mild Uncoupling' does not decrease mitochondrial superoxide levels in cultured cerebellar granule neurons but decreases spare respiratory capacity and increases toxicity to glutamate and oxidative stress. J Neurochem 2007; 101:1619-31. [PMID: 17437552 DOI: 10.1111/j.1471-4159.2007.04516.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cultured rat cerebellar granule neurons were incubated with low nanomolar concentrations of the protonophore carbonylcyanide-p-trifluoromethoxyphenyl hydrazone (FCCP) to test the hypothesis that 'mild uncoupling' could be neuroprotective by decreasing oxidative stress. To quantify the uncoupling, respiration and mitochondrial membrane potential (Deltapsi(m)) were determined in parallel as a function of FCCP concentration. Deltapsi(m) dropped by less than 10 mV before respiratory control was lost. Conditions for the valid estimation of matrix superoxide levels were determined from the rate of oxidation of the matrix-targeted fluorescent probe MitoSOX. No significant change in the level of matrix superoxide could be detected on addition of FCCP while respiratory control was retained, although cytoplasmic superoxide levels measured by dihydroethidium oxidation increased. 'Mild uncoupling' by 30 nmol/L FCCP did not alleviate neuronal dysregulation induced by glutathione depletion and significantly enhanced that due to menadione-induced oxidative stress. Low protonophore concentrations enhanced N-methyl-d-aspartate receptor-induced delayed calcium deregulation consistent with a decrease in the spare respiratory capacity available to match the bioenergetic demand of chronic receptor activation. It is concluded that the 'mild uncoupling' hypothesis is not supported by this model.
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Nicholls DG, Johnson-Cadwell L, Vesce S, Jekabsons M, Yadava N. Bioenergetics of mitochondria in cultured neurons and their role in glutamate excitotoxicity. J Neurosci Res 2007; 85:3206-12. [PMID: 17455297 DOI: 10.1002/jnr.21290] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The pathologic activation of NMDA receptors by glutamate is a major contributor to neuronal cell death after stroke. Receptor activation causes a massive influx of calcium into the neuron that is accumulated by the mitochondria. The favored hypothesis is that the calcium loaded mitochondria generate reactive oxygen species that damage and ultimately killed the neuron. In this review this hypothesis is critically re-examined with an emphasis on the role played by deficits in ATP generation. Novel techniques are developed to monitor the bioenergetic status of in situ mitochondria in cultured neurons. Applying these techniques to a model of glutamate excitotoxicity suggests that enhanced reactive oxygen species are a consequence rather than a cause of failed cytoplasmic calcium homeostasis (delayed calcium deregulation, [DCD]), but that prior oxidative damage facilitates DCD by damaging mitochondrial ATP generation. This impacts on current hypotheses relating to the neuroprotective effects of mild mitochondrial uncoupling.
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