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Rumbeiha WK, Kim DS, Min A, Nair M, Giulivi C. Disrupted brain mitochondrial morphology after in vivo hydrogen sulfide exposure. Sci Rep 2023; 13:18129. [PMID: 37875542 PMCID: PMC10598273 DOI: 10.1038/s41598-023-44807-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 10/12/2023] [Indexed: 10/26/2023] Open
Abstract
Changes in mitochondrial dynamics are often associated with dietary patterns, medical treatments, xenobiotics, and diseases. Toxic exposures to hydrogen sulfide (H2S) harm mitochondria by inhibiting Complex IV and via other mechanisms. However, changes in mitochondrial dynamics, including morphology following acute exposure to H2S, are not yet fully understood. This study followed mitochondrial morphology changes over time after a single acute LCt50 dose of H2S by examining electron microscopy thalami images of surviving mice. Our findings revealed that within the initial 48 h after H2S exposure, mitochondrial morphology was impaired by H2S, supported by the disruption and scarcity of the cristae, which are required to enhance the surface area for ATP production. At the 72-h mark point, a spectrum of morphological cellular changes was observed, and the disordered mitochondrial network, accompanied by the probable disruption of mitophagy, was tied to changes in mitochondrial shape. In summary, this study sheds light on how acute exposure to high levels of H2S triggers alterations in mitochondrial shape and structure as early as 24 h that become more evident at 72 h post-exposure. These findings underscore the impact of H2S on mitochondrial function and overall cellular health.
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Affiliation(s)
- Wilson K Rumbeiha
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
| | - Dong-Suk Kim
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Angela Min
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Maya Nair
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA
| | - Cecilia Giulivi
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, CA, USA.
- Medical Investigation of Neurodevelopmental Disorders (MIND) Institute UCDH, University of California Davis, Sacramento, CA, USA.
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Chiu LS, Anderton RS. The role of the microbiota-gut-brain axis in long-term neurodegenerative processes following traumatic brain injury. Eur J Neurosci 2023; 57:400-418. [PMID: 36494087 PMCID: PMC10107147 DOI: 10.1111/ejn.15892] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/13/2022]
Abstract
Traumatic brain injury (TBI) can be a devastating and debilitating disease to endure. Due to improvements in clinical practice, declining mortality rates have led to research into the long-term consequences of TBI. For example, the incidence and severity of TBI have been associated with an increased susceptibility of developing neurodegenerative disorders, such as Parkinson's or Alzheimer's disease. However, the mechanisms linking this alarming association are yet to be fully understood. Recently, there has been a groundswell of evidence implicating the microbiota-gut-brain axis in the pathogenesis of these diseases. Interestingly, survivors of TBI often report gastrointestinal complaints and animal studies have demonstrated gastrointestinal dysfunction and dysbiosis following injury. Autonomic dysregulation and chronic inflammation appear to be the main driver of these pathologies. Consequently, this review will explore the potential role of the microbiota-gut-brain axis in the development of neurodegenerative diseases following TBI.
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Affiliation(s)
- Li Shan Chiu
- School of Medicine, The University Notre Dame Australia, Fremantle, Western Australia, Australia
- Ear Science Institute Australia, Nedlands, Western Australia, Australia
| | - Ryan S Anderton
- Institute for Health Research, The University Notre Dame Australia, Fremantle, Western Australia, Australia
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Quintana DD, Garcia JA, Sarkar SN, Jun S, Engler-Chiurazzi EB, Russell AE, Cavendish JZ, Simpkins JW. Hypoxia-reoxygenation of primary astrocytes results in a redistribution of mitochondrial size and mitophagy. Mitochondrion 2019; 47:244-255. [PMID: 30594729 PMCID: PMC6980114 DOI: 10.1016/j.mito.2018.12.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 08/07/2018] [Accepted: 12/18/2018] [Indexed: 12/15/2022]
Abstract
Astrocytes serve to maintain proper neuronal function and support neuronal viability, but remain largely understudied in research of cerebral ischemia. Astrocytic mitochondria are core participants in the metabolic activity of astrocytes. The objective of this study is to assess astrocyte mitochondrial competence during hypoxia and post-hypoxia reoxygenation and to determine cellular adaptive and pathological changes in the mitochondrial network. We hypothesize that during metabolic distress in astrocytes; mitochondrial networks undergo a shift in fission-fusion dynamics that results in a change in the morphometric state of the entire mitochondrial network. This mitochondrial network shift may be protective during metabolic distress by priming mitochondrial size and facilitating mitophagy. We demonstrated that hypoxia and post-hypoxia reoxygenation of rat primary astrocytes results in a redistribution of mitochondria to smaller sizes evoked by increased mitochondrial fission. Excessive mitochondrial fission corresponded to Drp-1 dephosphorylation at Ser 637, which preceded mitophagy of relatively small mitochondria. Reoxygenation of astrocytes marked the initiation of elevated mitophagic activity primarily reserved to the perinuclear region where a large number of the smallest mitochondria occurred. Although, during hypoxia astrocytic ATP content was severely reduced, after reoxygenation ATP content returned to near normoxic values and these changes mirrored mitochondrial superoxide production. Concomitant with these changes in astrocytic mitochondria, the number of astrocytic extensions declined only after 10-hours post-hypoxic reoxygenation. Overall, we posit a drastic mitochondrial network change that is triggered by a metabolic crisis during hypoxia; these changes are followed by mitochondrial degradation and retraction of astrocytic extensions during reoxygenation.
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Affiliation(s)
- Dominic D Quintana
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - Jorge A Garcia
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - Saumyendra N Sarkar
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - Sujung Jun
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - Elizabeth B Engler-Chiurazzi
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - Ashley E Russell
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - John Z Cavendish
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States
| | - James W Simpkins
- Center for Basic and Translational Stroke Research, Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, United States.
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4
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Du B, Zhang L, Sun Y, Zhang G, Yao J, Jiang M, Pan L, Sun C. Phillygenin exhibits anti-inflammatory activity through modulating multiple cellular behaviors of mouse lymphocytes. Immunopharmacol Immunotoxicol 2019; 41:76-85. [PMID: 30721636 DOI: 10.1080/08923973.2018.1547742] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Context: Phillygenin (PHI) is an intestinal metabolite of phillyrin from the genus Forsythia. Although the regulatory activity of Forsythia on immune system has been investigated, the effect of PHI on activated lymphocytes is poorly understood. Objective: This study was aimed to discuss the possible anti-inflammation potential of PHI on mitogen-activated stimulated lymphocytes in vitro. Methods: Mice spleen lymphocytes were incubated with PHI for 4 h, and then stimulated with concanavalin A (Con A) or phorbol 12-myristate 13-acetate/ionomycin (PMA + Ion). Cell viability was assayed by cell counting kit-8 (CCK-8). The expression of CD69 and CD25, proliferation, cell cycle, intracellular Ca2+ concentration, apoptosis, mitochondrial inner membrane potential (ΔΨm), mitochondrial permeability transition (MPT), interleukin-2 (IL-2), interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α) were analyzed by flow cytometry. The expression of cyclin B1, cyclin D1, Cyclin E, and the phosphorylation of c-jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (Erk1/2) and p38 were assayed by western blotting. Results: The results showed that PHI inhibited the proliferation of Con A-activated lymphocytes and induced a G0/G1 phase arrest by suppressing cyclin D1 and cyclin E. Meanwhile, PHI antagonized Con A-induced T cells activation through blocking intracellular Ca2+ overload and suppressing the phosphorylation of JNK and Erk1/2. Both Con A and PMA + Ion-induced secretion of IL-2, IFN-γ, and TNF-α were attenuated by PHI. PHI enhanced Con A-induced lymphocytes apoptosis through decreasing ΔΨm and increasing MPT. Conclusion: These results suggest that PHI exhibits its anti-inflammatory activity through modulating multiple cellular behaviors, leading to the suppression of the adaptive immune response.
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Affiliation(s)
- Bingyuan Du
- a State Key Laboratory of Generic Manufacture Technology of Chinese Traditional Medicine , Linyi , PR China.,b Linyi Key Laboratory for Immunopharmacology and Immunotoxicology of Natural Medicine , Linyi , PR China.,c Center for New Drug Pharmacology , Lunan Pharmaceutical Group Corporation , Linyi , PR China
| | - Li Zhang
- a State Key Laboratory of Generic Manufacture Technology of Chinese Traditional Medicine , Linyi , PR China
| | - Ying Sun
- a State Key Laboratory of Generic Manufacture Technology of Chinese Traditional Medicine , Linyi , PR China
| | - Guimin Zhang
- a State Key Laboratory of Generic Manufacture Technology of Chinese Traditional Medicine , Linyi , PR China.,b Linyi Key Laboratory for Immunopharmacology and Immunotoxicology of Natural Medicine , Linyi , PR China
| | - Jingchun Yao
- a State Key Laboratory of Generic Manufacture Technology of Chinese Traditional Medicine , Linyi , PR China.,b Linyi Key Laboratory for Immunopharmacology and Immunotoxicology of Natural Medicine , Linyi , PR China.,c Center for New Drug Pharmacology , Lunan Pharmaceutical Group Corporation , Linyi , PR China
| | - Mingmin Jiang
- a State Key Laboratory of Generic Manufacture Technology of Chinese Traditional Medicine , Linyi , PR China.,b Linyi Key Laboratory for Immunopharmacology and Immunotoxicology of Natural Medicine , Linyi , PR China.,c Center for New Drug Pharmacology , Lunan Pharmaceutical Group Corporation , Linyi , PR China
| | - Lihong Pan
- a State Key Laboratory of Generic Manufacture Technology of Chinese Traditional Medicine , Linyi , PR China.,b Linyi Key Laboratory for Immunopharmacology and Immunotoxicology of Natural Medicine , Linyi , PR China.,c Center for New Drug Pharmacology , Lunan Pharmaceutical Group Corporation , Linyi , PR China
| | - Chenghong Sun
- a State Key Laboratory of Generic Manufacture Technology of Chinese Traditional Medicine , Linyi , PR China.,b Linyi Key Laboratory for Immunopharmacology and Immunotoxicology of Natural Medicine , Linyi , PR China.,c Center for New Drug Pharmacology , Lunan Pharmaceutical Group Corporation , Linyi , PR China
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Kim DY, Zhang FX, Nakanishi ST, Mettler T, Cho IH, Ahn Y, Hiess F, Chen L, Sullivan PG, Chen SRW, Zamponi GW, Rho JM. Carisbamate blockade of T-type voltage-gated calcium channels. Epilepsia 2017; 58:617-626. [PMID: 28230232 DOI: 10.1111/epi.13710] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2017] [Indexed: 01/23/2023]
Abstract
OBJECTIVES Carisbamate (CRS) is a novel monocarbamate compound that possesses antiseizure and neuroprotective properties. However, the mechanisms underlying these actions remain unclear. Here, we tested both direct and indirect effects of CRS on several cellular systems that regulate intracellular calcium concentration [Ca2+ ]i . METHODS We used a combination of cellular electrophysiologic techniques, as well as cell viability, Store Overload-Induced Calcium Release (SOICR), and mitochondrial functional assays to determine whether CRS might affect [Ca2+ ]i levels through actions on the endoplasmic reticulum (ER), mitochondria, and/or T-type voltage-gated Ca2+ channels. RESULTS In CA3 pyramidal neurons, kainic acid induced significant elevations in [Ca2+ ]i and long-lasting neuronal hyperexcitability, both of which were reversed in a dose-dependent manner by CRS. Similarly, CRS suppressed spontaneous rhythmic epileptiform activity in hippocampal slices exposed to zero-Mg2+ or 4-aminopyridine. Treatment with CRS also protected murine hippocampal HT-22 cells against excitotoxic injury with glutamate, and this was accompanied by a reduction in [Ca2+ ]i . Neither kainic acid nor CRS alone altered the mitochondrial membrane potential (ΔΨ) in intact, acutely isolated mitochondria. In addition, CRS did not affect mitochondrial respiratory chain activity, Ca2+ -induced mitochondrial permeability transition, and Ca2+ release from the ER. However, CRS significantly decreased Ca2+ flux in human embryonic kidney tsA-201 cells transfected with Cav 3.1 (voltage-dependent T-type Ca2+ ) channels. SIGNIFICANCE Our data indicate that the neuroprotective and antiseizure activity of CRS likely results in part from decreased [Ca2+ ]i accumulation through blockade of T-type Ca2+ channels.
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Affiliation(s)
- Do Young Kim
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital & Medical Center, Phoenix, Arizona, U.S.A
| | - Fang-Xiong Zhang
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Stan T Nakanishi
- Department of Biology, University of Hawaii at Hilo, Hilo, Hawaii, U.S.A
| | - Timothy Mettler
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital & Medical Center, Phoenix, Arizona, U.S.A
| | - Ik-Hyun Cho
- Departments of Neurology and Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital & Medical Center, Phoenix, Arizona, U.S.A
| | - Younghee Ahn
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Florian Hiess
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Lina Chen
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada
| | - Patrick G Sullivan
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, U.S.A
| | - S R Wayne Chen
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Jong M Rho
- Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
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6
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Peptide Pharmacological Approaches to Treating Traumatic Brain Injury: a Case for Arginine-Rich Peptides. Mol Neurobiol 2016; 54:7838-7857. [PMID: 27844291 DOI: 10.1007/s12035-016-0287-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 11/02/2016] [Indexed: 01/25/2023]
Abstract
Traumatic brain injury (TBI) has a devastating effect on victims and their families, and has profound negative societal and economic impacts, a situation that is further compounded by the lack of effective treatments to minimise injury after TBI. The current strategy for managing TBI is partly through preventative measures and partly through surgical and rehabilitative interventions. Secondary brain damage remains the principal focus for the development of a neuroprotective therapeutic. However, the complexity of TBI pathophysiology has meant that single-action pharmacological agents have been largely unsuccessful in combatting the associated brain injury cascades, while combination therapies to date have proved equally ineffective. Peptides have recently emerged as promising lead agents for the treatment of TBI, especially those rich in the cationic amino acid, arginine. Having been shown to lessen the impact of ischaemic stroke in animal models, there are reasonable grounds to believe that arginine-rich peptides may have neuroprotective therapeutic potential in TBI. Here, we review a range of peptides previously examined as therapeutic agents for TBI. In particular, we focus on cationic arginine-rich peptides -- a new class of agents that growing evidence suggests acts through multiple neuroprotective mechanisms.
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7
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Al-Shamsi M, Shahin A, Ibrahim MF, Tareq S, Souid AK, Mensah-Brown EPK. Bioenergetics of the spinal cord in experimental autoimmune encephalitis of rats. BMC Neurosci 2015; 16:37. [PMID: 26092157 PMCID: PMC4474435 DOI: 10.1186/s12868-015-0175-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 06/10/2015] [Indexed: 12/16/2022] Open
Abstract
Background Mitochondrial dysregulation is important in axonal damage and demyelination in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). There is however, no evidence in the literature of any study that has examined cellular bioenergetics of the central nervous system (CNS) during the early development and clinical course of EAE. EAE, a rodent model of relapsing/remitting MS, is a CD4+ T cell-mediated disease of the CNS. We hypothesize that CNS bioenergetics might predict prognosis, and that preserved bioenergetics might underlie the remission from disease. The study aims therefore, to determine whether the clinical history of EAE is influenced by cellular respiration of the CNS in susceptible Dark Agouti (DA) and resistant Albino Oxford (AO) rats. Methods Experimental autoimmune encephalomyelitis was induced by myelin basic protein in complete Freud Adjuvant in the footpads of DA and AO rats. A phosphorescence analyzer that determines cellular respiration was used to monitor oxygen consumption and ATP concentration was measured using the Enliten ATP assay system. Disease pathology was demonstrated by H&E and Luxol fast blue staining of sections of the lumbar regions of the spinal cord. Mitochondrial size in relation to axonal size was determined by electron microscopy. Apoptosis was studied by HPLC measurement of intracellular caspase-3 activity and caspase immunohistochemistry. Role and source of caspase 1 was studied by double immunofluorescence with antibodies for caspase-1, microglia (anti-Iba1) and astrocytes (anti-GFAP). Results The cellular respiration of the CNS did not vary between diseased and normal rats. We also demonstrate here, that at the peak of disease, inflammation as shown by caspase-1, produced by activated microglia and infiltrating cells, was significant in susceptible DA rats. The mitochondrial:axonal size ratio did not vary in the different groups although mitochondria were smaller in spinal cords of diseased DA rats. Demyelination, observed only in areas of mononuclear infiltration of the spinal cord of diseased DA rats, was demonstrated by light microscopy and electron microscopy. Conclusion We conclude that EAE at this early stage does not significantly affect CNS cellular respiration and this might underlie the reason for the recovery of diseased rats.
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Affiliation(s)
- Mariam Al-Shamsi
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE.
| | - Allen Shahin
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE.
| | - Marwa F Ibrahim
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE.
| | - Saeed Tareq
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE.
| | - Abdul-Kader Souid
- Department of Pediatrics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE.
| | - Eric P K Mensah-Brown
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, UAE.
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8
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Deheshi S, Dabiri B, Fan S, Tsang M, Rintoul GL. Changes in mitochondrial morphology induced by calcium or rotenone in primary astrocytes occur predominantly through ros-mediated remodeling. J Neurochem 2015; 133:684-99. [PMID: 25761412 DOI: 10.1111/jnc.13090] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 02/12/2015] [Accepted: 02/18/2015] [Indexed: 12/17/2022]
Abstract
Morphological changes in mitochondria have been primarily attributed to fission and fusion, while the more pliable transformations of mitochondria (remodeling, rounding, or stretching) have been largely overlooked. In this study, we quantify the contributions of fission and remodeling to changes in mitochondrial morphology induced by the Ca(2+) ionophore 4Br-A23187 and the metabolic toxin rotenone. We also examine the role of reactive oxygen species (ROS) in the regulation of mitochondrial remodeling. In agreement with our previous studies, mitochondrial remodeling, not fission, is the primary contributor to Ca(2+) -mediated changes in mitochondrial morphology induced by 4Br-A23187 in rat cortical astrocytes. Treatment with rotenone produced similar results. In both paradigms, remodeling was selectively blocked by antioxidants whereas fission was not, suggesting a ROS-mediated mechanism for mitochondrial remodeling. In support of this hypothesis, inhibition of endogenous ROS by overnight incubation in antioxidants resulted in elongated reticular networks of mitochondria. Examination of inner and outer mitochondrial membranes revealed that they largely acted in concert during the remodeling process. While mitochondrial morphology is traditionally ascribed to a net output of fission and fusion processes, in this study we provide evidence that the acute pliability of mitochondria can be a dominant factor in determining their morphology. More importantly, our results suggest that the remodeling process is independently regulated through a ROS-signaling mechanism. Mitochondrial morphology is traditionally ascribed to a balance of fission and fusion processes. We have shown that mitochondria can undergo more pliable transformations; remodeling, rounding, or stretching. We demonstrate that remodeling, not fission, is the primary contributor to calcium mediated changes in mitochondrial morphology in primary astrocytes. Others have shown fission is mediated by calcineurin. Our results suggest the remodeling process distinct from fission and is independently regulated through a ROS-signaling mechanism (CsA: Cyclosporine A; NAC: N-acetyl-l-cysteine; GSH: Reduced-L-Glutathione).
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Affiliation(s)
- Samineh Deheshi
- Department of Biological Sciences, Simon Fraser University, Burnaby, BC, Canada
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N-acetylcysteineamide protects against manganese-induced toxicity in SHSY5Y cell line. Brain Res 2015; 1608:157-66. [PMID: 25681547 DOI: 10.1016/j.brainres.2015.02.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 02/03/2015] [Accepted: 02/04/2015] [Indexed: 12/21/2022]
Abstract
Manganese (Mn) is an essential trace element required for normal cellular functioning. However, overexposure of Mn can be neurotoxic resulting in the development of manganism, a syndrome that resembles Parkinson׳s disease. Although the pathogenetic basis of this disorder is unclear, several studies indicate that it is mainly associated with oxidative stress and mitochondrial energy failure. Therefore, this study is focused on (1) investigating the oxidative effects of Mn on neuroblastoma cells (SHSY5Y) and (2) elucidating whether a novel thiol antioxidant, N-acetylcysteineamide (NACA), provides any protection against Mn-induced neurotoxicity. Reactive oxygen species (ROS) were highly elevated after the exposure, indicating that mechanisms that induce oxidative stress were involved. Measures of oxidative stress parameters, such as glutathione (GSH), malondialdehyde (MDA), and activities of glutathione reductase (GR) and glutathione peroxidase (GPx) were altered in the Mn-treated groups. Loss of mitochondrial membrane potential, as assessed by flow cytometry and decreased levels of ATP, indicated that cytotoxicity was mediated through mitochondrial dysfunction. However, pretreatment with NACA protected against Mn-induced toxicity by inhibiting lipid peroxidation, scavenging ROS, and preserving intracellular GSH and mitochondrial membrane potential. NACA can potentially be developed into a promising therapeutic option for Mn-induced neurotoxicity. This article is part of a Special Issue entitled SI: Metals in neurodegeneration.
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10
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The roads to mitochondrial dysfunction in a rat model of posttraumatic syringomyelia. BIOMED RESEARCH INTERNATIONAL 2015; 2015:831490. [PMID: 25685811 PMCID: PMC4309244 DOI: 10.1155/2015/831490] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 10/13/2014] [Indexed: 11/26/2022]
Abstract
The pathophysiology of posttraumatic syringomyelia is incompletely understood. We examined whether local ischemia occurs after spinal cord injury. If so, whether it causes neuronal mitochondrial dysfunction and depletion, and subsequent energy metabolism impairment results in cell starvation of energy and even cell death, contributing to the enlargement of the cavity. Local blood flow was measured in a rat model of posttraumatic syringomyelia that had received injections of quisqualic acid and kaolin. We found an 86 ± 11% reduction of local blood flow at C8 where a cyst formed at 6 weeks after syrinx induction procedure (P < 0.05), and no difference in blood flow rate between the laminectomy and intact controls. Electron microscopy confirmed irreversible neuronal mitochondrion depletion surrounding the cyst, but recoverable mitochondrial loses in laminectomy rats. Profound energy loss quantified in the spinal cord of syrinx animals, and less ATP and ADP decline observed in laminectomy rats. Our findings demonstrate that an excitotoxic injury induces local ischemia in the spinal cord and results in neuronal mitochondrial depletion, and profound ATP loss, contributing to syrinx enlargement. Ischemia did not occur following laminectomy induced trauma in which mitochondrial loss and decline in ATP were reversible. This confirms excitotoxic injury contributing to the pathology of posttraumatic syringomyelia.
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11
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Yu Z, Liu N, Li Y, Xu J, Wang X. Neuroglobin overexpression inhibits oxygen-glucose deprivation-induced mitochondrial permeability transition pore opening in primary cultured mouse cortical neurons. Neurobiol Dis 2013; 56:95-103. [PMID: 23639789 DOI: 10.1016/j.nbd.2013.04.015] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 03/23/2013] [Accepted: 04/09/2013] [Indexed: 12/14/2022] Open
Abstract
Neuroglobin (Ngb) is an endogenous neuroprotective molecule against hypoxic/ischemic brain injury, but the underlying mechanisms remain largely undefined. Our recent study revealed that Ngb can bind to voltage-dependent anion channel (VDAC), a regulator of mitochondria permeability transition (MPT). In this study we examined the role of Ngb in MPT pore (mPTP) opening following oxygen-glucose deprivation (OGD) in primary cultured mouse cortical neurons. Co-immunoprecipitation (Co-IP) and immunocytochemistry showed that the binding between Ngb and VDAC was increased after OGD compared to normoxia, indicating the OGD-enhanced Ngb-VDAC interaction. Ngb overexpression protected primary mouse cortical neurons from OGD-induced neuronal death, to an extent comparable to mPTP opening inhibitor, cyclosporine A (CsA) pretreatment. We further measured the role of Ngb in OGD-induced mPTP opening using Ngb overexpression and knockdown approaches in primary cultured neurons, and recombinant Ngb exposure to isolated mitochondria. Same as CsA pretreatment, Ngb overexpression significantly reduced OGD-induced mPTP opening markers including mitochondria swelling, mitochondrial NAD(+) release, and cytochrome c (Cyt c) release in primary cultured neurons. Recombinant Ngb incubation significantly reduced OGD-induced NAD(+) release and Cyt c release from isolated mitochondria. In contrast, Ngb knockdown significantly increased OGD-induced neuron death, and increased OGD-induced mitochondrial NAD(+) release and Cyt c release as well, and these outcomes could be rescued by CsA pretreatment. In summary, our results demonstrated that Ngb overexpression can inhibit OGD-induced mPTP opening in primary cultured mouse cortical neurons, which may be one of the molecular mechanisms of Ngb's neuroprotection.
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Affiliation(s)
- Zhanyang Yu
- Neuroprotection Research Laboratory, Department of Neurology, Massachusetts General Hospital, and Program in Neuroscience, Harvard Medical School, Charlestown, MA 02129, USA.
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12
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Guo L, Du H, Yan S, Wu X, McKhann GM, Chen JX, Yan SS. Cyclophilin D deficiency rescues axonal mitochondrial transport in Alzheimer's neurons. PLoS One 2013; 8:e54914. [PMID: 23382999 PMCID: PMC3561411 DOI: 10.1371/journal.pone.0054914] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 12/17/2012] [Indexed: 11/24/2022] Open
Abstract
Normal axonal mitochondrial transport and function is essential for the maintenance of synaptic function. Abnormal mitochondrial motility and mitochondrial dysfunction within axons are critical for amyloid β (Aβ)-induced synaptic stress and the loss of synapses relevant to the pathogenesis of Alzheimer's disease (AD). However, the mechanisms controlling axonal mitochondrial function and transport alterations in AD remain elusive. Here, we report an unexplored role of cyclophilin D (CypD)-dependent mitochondrial permeability transition pore (mPTP) in Aβ-impaired axonal mitochondrial trafficking. Depletion of CypD significantly protects axonal mitochondrial motility and dynamics from Aβ toxicity as shown by increased axonal mitochondrial density and distribution and improved bidirectional transport of axonal mitochondria. Notably, blockade of mPTP by genetic deletion of CypD suppresses Aβ-mediated activation of the p38 mitogen-activated protein kinase signaling pathway, reverses axonal mitochondrial abnormalities, improves synaptic function, and attenuates loss of synapse, suggesting a role of CypD-dependent signaling in Aβ-induced alterations in axonal mitochondrial trafficking. The potential mechanisms of the protective effects of lacking CypD on Aβ-induced abnormal mitochondrial transport in axon are increased axonal calcium buffer capability, diminished reactive oxygen species (ROS), and suppressing downstream signal transduction P38 activation. These findings provide new insights into CypD-dependent mitochondrial mPTP and signaling on mitochondrial trafficking in axons and synaptic degeneration in an environment enriched for Aβ.
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Affiliation(s)
- Lan Guo
- Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, Kansas, United States of America
| | - Heng Du
- Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, Kansas, United States of America
| | - Shiqiang Yan
- Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, Kansas, United States of America
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu, People’s Republic of China
| | - Xiaoping Wu
- Department of Neurosurgery, Physicians & Surgeons College of Columbia University, New York, New York, United States of America
| | - Guy M. McKhann
- Department of Neurosurgery, Physicians & Surgeons College of Columbia University, New York, New York, United States of America
| | - John Xi Chen
- Department of Neurology, Memorial Sloan-Kettering Cancer Center, New York, New York, United States of America
| | - Shirley ShiDu Yan
- Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, Kansas, United States of America
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13
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Kitay BM, McCormack R, Wang Y, Tsoulfas P, Zhai RG. Mislocalization of neuronal mitochondria reveals regulation of Wallerian degeneration and NMNAT/WLD(S)-mediated axon protection independent of axonal mitochondria. Hum Mol Genet 2013; 22:1601-14. [PMID: 23314018 DOI: 10.1093/hmg/ddt009] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Axon degeneration is a common and often early feature of neurodegeneration that correlates with the clinical manifestations and progression of neurological disease. Nicotinamide mononucleotide adenylytransferase (NMNAT) is a neuroprotective factor that delays axon degeneration following injury and in models of neurodegenerative diseases suggesting a converging molecular pathway of axon self-destruction. The underlying mechanisms have been under intense investigation and recent reports suggest a central role for axonal mitochondria in both degeneration and NMNAT/WLD(S) (Wallerian degeneration slow)-mediated protection. We used dorsal root ganglia (DRG) explants and Drosophila larval motor neurons (MNs) as models to address the role of mitochondria in Wallerian degeneration (WD). We find that expression of Drosophila NMNAT delays WD in human DRG neurons demonstrating evolutionary conservation of NMNAT function. Morphological comparison of mitochondria from WLD(S)-protected axons demonstrates that mitochondria shrink post-axotomy, though analysis of complex IV activity suggests that they retain their functional capacity despite this morphological change. To determine whether mitochondria are a critical site of regulation for WD, we genetically ablated mitochondria from Drosophila MN axons via the mitochondria trafficking protein milton. Milton loss-of-function did not induce axon degeneration in Drosophila larval MNs, and when axotomized WD proceeded stereotypically in milton distal axons although with a mild, but significant delay. Remarkably, the protective effects of NMNAT/WLD(S) were also maintained in axons devoid of mitochondria. These experiments unveil an axon self-destruction cascade governing WD that is not initiated by axonal mitochondria and for the first time illuminate a mitochondria-independent mechanism(s) regulating WD and NMNAT/WLD(S)-mediated axon protection.
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Affiliation(s)
- Brandon M Kitay
- Department of Molecular and Cellular Pharmacology, University of Miami School of Medicine, Miami, FL 33136, USA
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14
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Fu Z, Kuang HY, Hao M, Gao XY, Liu Y, Shao N. Protection of exenatide for retinal ganglion cells with different glucose concentrations. Peptides 2012; 37:25-31. [PMID: 22727809 DOI: 10.1016/j.peptides.2012.06.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Revised: 06/12/2012] [Accepted: 06/12/2012] [Indexed: 12/30/2022]
Abstract
Exendin-4 is a peptide resembling glucagon-like peptide-1 (GLP-1), which has protective effects on nerve cells. However, the effects of Exendin-4 on retinal ganglion cells (RGC) are still under clear. The purpose of the present study is to demonstrate that exenatide prevents high- or low-glucose-induced retinal ganglion cell impairment. We observed the expression of GLP-1R in RGC-5 cells by immunofluorescence and Western blot. To investigate the effect of exenatide on RGC-5 cells incubated different glucose concentrations, CCK-8 measured the survival rates and electron microscopy detected cellular injury. The expression levels of Bcl-2 and Bax were analyzed by immunocytochemistry and Western blot. Exenatide protects RGC-5 from high- or low-glucose-induced cellular injury and the optimum concentration was 0.5μg/ml. Exenatide can inhibit high- or low-glucose-induced mitochondrial changes. Exenatide protects RGC-5 from high- or low-glucose-induced Bax increased and Bcl-2 decreased. Furthermore, the protective effect of exenatide could be inhibited by Exendin (9-39). These findings indicate that exenatide shows a neuroprotective effect for different glucose concentrations-induced RGC-5 cells injury. Exenatide could protect RGC-5 cells from degeneration or death, which may protect retinal function and have a potential value for patients with diabetic retinopathy.
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Affiliation(s)
- Zheng Fu
- Department of Endocrinology, Ningde Hospital, 352100 Fujian Province, China
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15
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Hao M, Kuang HY, Fu Z, Gao XY, Liu Y, Deng W. Exenatide prevents high-glucose-induced damage of retinal ganglion cells through a mitochondrial mechanism. Neurochem Int 2012; 61:1-6. [DOI: 10.1016/j.neuint.2012.04.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 04/01/2012] [Accepted: 04/10/2012] [Indexed: 12/31/2022]
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16
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Song B, Tang X, Wang X, Huang X, Ye Y, Lu X, Wei X, Zeng Y. Bererine induces peripheral lymphocytes immune regulations to realize its neuroprotective effects in the cerebral ischemia/reperfusion mice. Cell Immunol 2012; 276:91-100. [DOI: 10.1016/j.cellimm.2012.04.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 02/20/2012] [Accepted: 04/05/2012] [Indexed: 11/26/2022]
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17
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Ye Y, Zhang Y, Lu X, Huang X, Zeng X, Lai X, Zeng Y. The anti-inflammatory effect of the SOCC blocker SK&F 96365 on mouse lymphocytes after stimulation by Con A or PMA/ionomycin. Immunobiology 2011; 216:1044-53. [DOI: 10.1016/j.imbio.2011.03.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2010] [Revised: 03/03/2011] [Accepted: 03/05/2011] [Indexed: 11/24/2022]
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18
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FK506 ameliorates cell death features in Huntington's disease striatal cell models. Neurochem Int 2011; 59:600-9. [PMID: 21703318 DOI: 10.1016/j.neuint.2011.04.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 03/17/2011] [Accepted: 04/18/2011] [Indexed: 11/23/2022]
Abstract
Huntington's disease (HD) is a genetic neurodegenerative disorder characterized by striatal neurodegeneration, involving apoptosis. FK506, an inhibitor of calcineurin (or protein phosphatase 3, formerly known as protein phosphatase 2B), has shown neuroprotective effects in several cellular and animal models of HD. In the present study, we show the protective effects of FK506 in two striatal HD models, primary rat striatal neurons treated with 3-nitropropionic acid (3-NP) and immortalized striatal STHdh cells derived from HD knock-in mice expressing normal (STHdh(7/7)) or full-length mutant huntingtin (FL-mHtt) with 111 glutamines (STHdh(111/111)), under basal conditions and after exposure to 3-NP or staurosporine (STS). In rat striatal neurons, FK506 abolished 3-NP-induced increase in caspase-3 activation, DNA fragmentation/condensation and necrosis. Nevertheless, in STHdh(111/111) cells under basal conditions, FK506 did not prevent, in a significant manner, the release of cytochrome c and apoptosis inducing factor (AIF) from mitochondria, or alter Bax/Bcl-2 ratio, but significantly reverted caspase-3 activation. In STHdh(111/111) cells treated with 0.3mM 3-NP or 25 nM STS, linked to high necrosis, exposure to FK506 exerted no significant effects on caspase-3 activation. However, treatment of STHdh(111/111) cells exposed to 10nM STS with FK506 effectively prevented cell death by apoptosis and moderate necrosis. The results suggest that FK506 may be neuroprotective against apoptosis and necrosis under mild cell death stimulus in the presence of FLmHtt.
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Tan AR, Cai AY, Deheshi S, Rintoul GL. Elevated intracellular calcium causes distinct mitochondrial remodelling and calcineurin-dependent fission in astrocytes. Cell Calcium 2011; 49:108-14. [DOI: 10.1016/j.ceca.2010.12.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2010] [Revised: 12/01/2010] [Accepted: 12/02/2010] [Indexed: 11/26/2022]
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20
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Cross JL, Meloni BP, Bakker AJ, Lee S, Knuckey NW. Modes of Neuronal Calcium Entry and Homeostasis following Cerebral Ischemia. Stroke Res Treat 2010; 2010:316862. [PMID: 21052549 PMCID: PMC2968719 DOI: 10.4061/2010/316862] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 09/29/2010] [Indexed: 01/14/2023] Open
Abstract
One of the major instigators leading to neuronal cell death and brain damage following cerebral ischemia is calcium dysregulation. The neuron's inability to maintain calcium homeostasis is believed to be a result of increased calcium influx and impaired calcium extrusion across the plasma membrane. The need to better understand the cellular and biochemical mechanisms of calcium dysregulation contributing to neuronal loss following stroke/cerebral ischemia is essential for the development of new treatments in order to reduce ischemic brain injury. The aim of this paper is to provide a concise overview of the various calcium influx pathways in response to ischemia and how neuronal cells attempts to overcome this calcium overload.
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Affiliation(s)
- J L Cross
- Centre for Neuromuscular and Neurological Disorders, Australian Neuromuscular Research Institute, University of Western Australia, WA 6009, Australia
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21
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22
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Sigma-1 receptors regulate hippocampal dendritic spine formation via a free radical-sensitive mechanism involving Rac1xGTP pathway. Proc Natl Acad Sci U S A 2009; 106:22468-73. [PMID: 20018732 DOI: 10.1073/pnas.0909089106] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Sigma-1 receptors (Sig-1Rs) are endoplasmic reticulum (ER)-resident proteins known to be involved in learning and memory. Dendritic spines in hippocampal neurons play important roles in neuroplasticity and learning and memory. This study tested the hypothesis that Sig-1Rs might regulate denritic spine formation in hippocampal neurons and examined potential mechanisms therein. In rat hippocampal primary neurons, the knockdown of Sig-1Rs by siRNAs causes a deficit in the formation of dendritic spines that is unrelated to ER Ca(2+) signaling or apoptosis, but correlates with the mitochondrial permeability transition and cytochrome c release, followed by caspase-3 activation, Tiam1 cleavage, and a reduction in Rac1.GTP. Sig-1R-knockdown neurons contain higher levels of free radicals when compared to control neurons. The activation of superoxide dismutase or the application of the hydroxyl-free radical scavenger N-acetyl cysteine (NAC) to the Sig-1R-knockdown neurons rescues dendritic spines and mitochondria from the deficits caused by Sig-1R siRNA. Further, the caspase-3-resistant TIAM1 construct C1199DN, a stable guanine exchange factor able to constitutively activate Rac1 in the form of Rac1.GTP, also reverses the siRNA-induced dendritic spine deficits. In addition, constitutively active Rac1.GTP reverses this deficit. These results implicate Sig-1Rs as endogenous regulators of hippopcampal dendritic spine formation and suggest a free radical-sensitive ER-mitochondrion-Rac1.GTP pathway in the regulation of dendritic spine formation in the hippocampus.
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23
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Comparative study of quercetin and its two glycoside derivatives quercitrin and rutin against methylmercury (MeHg)-induced ROS production in rat brain slices. Arch Toxicol 2009; 84:89-97. [DOI: 10.1007/s00204-009-0482-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 10/15/2009] [Indexed: 12/14/2022]
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24
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Rintoul GL, Reynolds IJ. Mitochondrial trafficking and morphology in neuronal injury. Biochim Biophys Acta Mol Basis Dis 2009; 1802:143-50. [PMID: 19747973 DOI: 10.1016/j.bbadis.2009.09.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2009] [Revised: 09/05/2009] [Accepted: 09/08/2009] [Indexed: 01/05/2023]
Abstract
Alterations in mitochondrial function may have a central role in the pathogenesis of many neurodegenerative diseases. The study of mitochondrial dysfunction has typically focused on ATP generation, calcium homeostasis and the production of reactive oxygen species. However, there is a growing appreciation of the dynamic nature of mitochondria within cells. Mitochondria are highly motile organelles, and also constantly undergo fission and fusion. This raises the possibility that impairment of mitochondrial dynamics could contribute to the pathogenesis of neuronal injury. In this review we describe the mechanisms that govern mitochondrial movement, fission and fusion. The key proteins that are involved in mitochondrial fission and fusion have also been linked to some inherited neurological diseases, including autosomal dominant optic atrophy and Charcot-Marie-Tooth disease 2A. We will discuss the evidence that altered movement, fission and fusion are associated with impaired neuronal viability. There is a growing collection of literature that links impaired mitochondrial dynamics to a number of disease models. Additionally, the concept that the failure to deliver a functional mitochondrion to the appropriate site within a neuron could contribute to neuronal dysfunction provides an attractive framework for understanding the mechanisms underlying neurologic disease. However, it remains difficult to clearly establish that altered mitochondrial dynamics clearly represent a cause of neuronal dysfunction.
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Affiliation(s)
- Gordon L Rintoul
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada V5A1S6
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25
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Quintanilla RA, Matthews-Roberson TA, Dolan PJ, Johnson GVW. Caspase-cleaved tau expression induces mitochondrial dysfunction in immortalized cortical neurons: implications for the pathogenesis of Alzheimer disease. J Biol Chem 2009; 284:18754-66. [PMID: 19389700 PMCID: PMC2707209 DOI: 10.1074/jbc.m808908200] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 03/25/2009] [Indexed: 11/06/2022] Open
Abstract
In Alzheimer disease (AD) mitochondrial abnormalities occur early in the pathogenic process and likely play a significant role in disease progression. Tau is a microtubule-associated protein that is abnormally processed in AD, and a connection between tau pathology and mitochondrial impairment has been proposed. However, few studies have examined the relationship between pathological forms of tau and mitochondrial dysfunction. We recently demonstrated that inducible expression of tau truncated at Asp-421 to mimic caspase cleavage (T4C3) was toxic to immortalized cortical neurons compared with a full-length tau isoform (T4). In this study we investigated the effects of T4C3 on mitochondrial function. Expression of T4C3 induced mitochondrial fragmentation and elevated oxidative stress levels in comparison with T4-expressing cells. Thapsigargin treatment of T4 or T4C3 cells, which causes an increase in intracellular calcium levels, resulted in a significant decrease in mitochondrial potential and loss of mitochondrial membrane integrity in T4C3 cells when compared with cells expressing T4. The mitochondrial fragmentation and mitochondrial membrane damage were ameliorated in T4C3 cells by pretreatment with cyclosporine A or FK506, implicating the calcium-dependent phosphatase calcineurin in these pathogenic events. Increased calcineurin activity has been reported in AD brain, and thus, inhibition of this phosphatase may provide a therapeutic target for the treatment of AD.
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Affiliation(s)
- Rodrigo A. Quintanilla
- From the Department of Anesthesiology, University of Rochester, Rochester, New York 14642-0002
| | - Tori A. Matthews-Roberson
- the Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0017, and
- the Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - Philip J. Dolan
- the Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0017, and
- the Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
| | - Gail V. W. Johnson
- From the Department of Anesthesiology, University of Rochester, Rochester, New York 14642-0002
- the Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0017, and
- the Department of Pharmacology and Physiology, University of Rochester, Rochester, New York 14642
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26
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Stimulation of glutamate receptors in cultured hippocampal neurons causes Ca2+-dependent mitochondrial contraction. Cell Calcium 2009; 46:18-29. [PMID: 19409612 DOI: 10.1016/j.ceca.2009.03.017] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 03/27/2009] [Accepted: 03/30/2009] [Indexed: 11/21/2022]
Abstract
Cultured hippocampal neurons expressing mitochondrially-targeted enhanced yellow fluorescent protein (mito-eYFP) were used to quantitatively examine mitochondrial remodelling in response to excitotoxic glutamate. Mitochondrial morphology was evaluated using laser spinning-disk confocal microscopy followed by calibrated image processing and 3D image rendering. Glutamate triggered an increase in cytosolic Ca(2+) and mitochondrial depolarization accompanied by Ca(2+)-dependent morphological transformation of neuronal mitochondria from "thread-like" to rounded structures. The quantitative analysis of the mitochondrial remodelling revealed that exposure to glutamate resulted in a decrease in mitochondrial volume and surface area concurrent with an increase in sphericity of the organelles. NIM811, an inhibitor of the mitochondrial permeability transition, attenuated the glutamate-induced sustained increase in cytosolic Ca(2+) and suppressed mitochondrial remodelling in the majority of affected neurons, but it did not rescue mitochondrial membrane potential. Shortening, fragmentation, and formation of circular mitochondria with decreased volume and surface area accompanied mitochondrial depolarization with FCCP. However, FCCP-induced morphological alterations appeared to be distinctly different from mitochondrial remodelling caused by glutamate. Moreover, FCCP prevented glutamate-induced mitochondrial remodelling suggesting an important role of Ca(2+) influx into mitochondria in the morphological alterations. Consistent with this, in saponin-permeabilized neurons, Ca(2+) caused mitochondrial remodelling which could be prevented by Ru(360).
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27
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Diversity of neurodegenerative processes in the model of brain cortex tissue ischemia. Neurochem Int 2009; 54:322-9. [DOI: 10.1016/j.neuint.2008.12.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2008] [Revised: 12/09/2008] [Accepted: 12/15/2008] [Indexed: 11/21/2022]
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28
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Ma CJ, Kim SH, Lee KY, Oh T, Kim SY, Sung SH, Kim YC. ESP-102, a combined extract ofAngelica gigas,Saururus chinensisandSchizandra chinensis, protects against glutamate-induced toxicity in primary cultures of rat cortical cells. Phytother Res 2009; 23:1587-91. [DOI: 10.1002/ptr.2825] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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29
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Nicholls DG. Mitochondrial calcium function and dysfunction in the central nervous system. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2009; 1787:1416-24. [PMID: 19298790 DOI: 10.1016/j.bbabio.2009.03.010] [Citation(s) in RCA: 169] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2008] [Revised: 03/09/2009] [Accepted: 03/10/2009] [Indexed: 12/17/2022]
Abstract
The ability of isolated brain mitochondria to accumulate, store and release calcium has been extensively characterized. Extrapolation to the intact neuron led to predictions that the in situ mitochondria would reversibly accumulate Ca(2+) when the concentration of the cation in the vicinity of the mitochondria rose above the 'set-point' at which uptake and efflux were in balance, storing Ca(2+) as a complex with phosphate, and slowly releasing the cation when plasma membrane ion pumps lowered the cytoplasmic free Ca(2+). Excessive accumulation of the cation was predicted to lead to activation of the permeability transition, with catastrophic consequences for the neuron. Each of these predictions has been confirmed with intact neurons, and there is convincing evidence for the permeability transition in cellular Ca(2+) overload associated with glutamate excitotoxicity and stroke, while the neurodegenerative disease in which possible defects in mitochondrial Ca(2+) handling have been most intensively investigated is Huntington's Disease. In this brief review evidence that mitochondrial Ca(2+) transport is relevant to neuronal survival in these conditions will be discussed.
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Affiliation(s)
- David G Nicholls
- Buck Institute for Age Research, 8001 Redwood Boulevard, Novato, CA 94945, USA.
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30
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Sharikabad MN, Aronsen JM, Haugen E, Pedersen J, Møller ASW, Mørk HK, Aass HCD, Sejersted OM, Sjaastad I, Brørs O. Cardiomyocytes from postinfarction failing rat hearts have improved ischemia tolerance. Am J Physiol Heart Circ Physiol 2009; 296:H787-95. [PMID: 19136604 DOI: 10.1152/ajpheart.00796.2008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Altered myocardial Ca(2+) and Na(+) handling in congestive heart failure (CHF) may be expected to decrease the tolerance to ischemia by augmenting reperfusion Ca(2+) overload. The aim of the present study was to investigate tolerance to hypoxia-reoxygenation by measuring enzyme release, cell death, ATP level, and cell Ca(2+) and Na(+) in cardiomyocytes from failing rat hearts. CHF was induced in Wistar rats by ligation of the left coronary artery during isoflurane anesthesia, after which cardiac failure developed within 6 wk. Isolated cardiomyocytes were cultured for 24 h and subsequently exposed to 4 h of hypoxia and 2 h of reoxygenation. Cell damage was measured as lactate dehydrogenase (LD) release, cell death as propidium iodide uptake, and ATP by firefly luciferase assay. Cell Ca(2+) and Na(+) were determined with radioactive isotopes, and free intracellular Ca(2+) concentration ([Ca(2+)](i)) with fluo-3 AM. CHF cells showed less increase in LD release and cell death after hypoxia-reoxygenation and had less relative reduction in ATP level after hypoxia than sham cells. CHF cells accumulated less Na(+) than sham cells during hypoxia (117 vs. 267 nmol/mg protein). CHF cells maintained much lower [Ca(2+)](i) than sham cells during hypoxia (423 vs. 1,766 arbitrary units at 4 h of hypoxia), and exchangeable Ca(2+) increased much less in CHF than in sham cells (1.4 vs. 6.7 nmol/mg protein) after 120 min of reoxygenation. Ranolazine, an inhibitor of late Na(+) current, significantly attenuated both the increase in exchangeable Ca(2+) and the increase in LD release in sham cells after reoxygenation. This supports the suggestion that differences in Na(+) accumulation during hypoxia cause the observed differences in Ca(2+) accumulation during reoxygenation. Tolerance to hypoxia and reoxygenation was surprisingly higher in CHF than in sham cardiomyocytes, probably explained by lower hypoxia-mediated Na(+) accumulation and subsequent lower Ca(2+) accumulation in CHF after reoxygenation.
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31
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Bolshakov AP. Glutamate neurotoxicity: Perturbations of ionic homeostasis, mitochondrial dysfunction, and changes in cell functioning. NEUROCHEM J+ 2008. [DOI: 10.1134/s181971240803001x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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32
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Nasr P, Sullivan PG, Smith GM. Mitochondrial imaging in dorsal root ganglion neurons following the application of inducible adenoviral vector expressing two fluorescent proteins. J Neurosci Methods 2008; 172:185-94. [PMID: 18541307 PMCID: PMC2657596 DOI: 10.1016/j.jneumeth.2008.04.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Revised: 04/06/2008] [Accepted: 04/22/2008] [Indexed: 01/31/2023]
Abstract
Mitochondrial morphology and dynamics are known to vary considerably depending on the cell type and organism studied. The objective of this study was to assess the potential application of adenoviral-fluorescent protein constructs for long-term tracking of mitochondria in neurons. An adenoviral vector containing two fluorescent proteins, the enhanced green fluorescent protein (eGFP) targeted to the cytoplasm to highlight the neuronal processes, and the red fluorescent protein (RFP) directed to mitochondria under the control of an inducible promoter, facilitated an efficient and accurate method to study mitochondrial dynamics in long-term studies. Dorsal root ganglion neurons from rat embryos were cultured and infected. The infected neurons exhibited green fluorescence after 24h, while 16 h following induction with doxycycline, red fluorescence protein began to localize within mitochondria. The red fluorescent protein was transported into mitochondria at the cell body followed by distribution within processes. As the neurons aged, the expression of red fluorescent protein was confined to cytoplasmic vacuoles and not mitochondria. Further analysis suggested that the cytoplasmic vacuoles were likely of lysosomal origin. Taken together, the current study presents novel strategies to study the life history of cellular organelles such as mitochondria in long-term studies.
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Affiliation(s)
- Payman Nasr
- Department of Biological Sciences, Kent State University, Ashtabula, OH 44004, United States.
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Sanz-Blasco S, Valero RA, Rodríguez-Crespo I, Villalobos C, Núñez L. Mitochondrial Ca2+ overload underlies Abeta oligomers neurotoxicity providing an unexpected mechanism of neuroprotection by NSAIDs. PLoS One 2008; 3:e2718. [PMID: 18648507 PMCID: PMC2447871 DOI: 10.1371/journal.pone.0002718] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Accepted: 06/20/2008] [Indexed: 12/01/2022] Open
Abstract
Dysregulation of intracellular Ca2+ homeostasis may underlie amyloid β peptide (Aβ) toxicity in Alzheimer's Disease (AD) but the mechanism is unknown. In search for this mechanism we found that Aβ1–42 oligomers, the assembly state correlating best with cognitive decline in AD, but not Aβ fibrils, induce a massive entry of Ca2+ in neurons and promote mitochondrial Ca2+ overload as shown by bioluminescence imaging of targeted aequorin in individual neurons. Aβ oligomers induce also mitochondrial permeability transition, cytochrome c release, apoptosis and cell death. Mitochondrial depolarization prevents mitochondrial Ca2+ overload, cytochrome c release and cell death. In addition, we found that a series of non-steroidal anti-inflammatory drugs (NSAIDs) including salicylate, sulindac sulfide, indomethacin, ibuprofen and R-flurbiprofen depolarize mitochondria and inhibit mitochondrial Ca2+ overload, cytochrome c release and cell death induced by Aβ oligomers. Our results indicate that i) mitochondrial Ca2+ overload underlies the neurotoxicity induced by Aβ oligomers and ii) inhibition of mitochondrial Ca2+ overload provides a novel mechanism of neuroprotection by NSAIDs against Aβ oligomers and AD.
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Affiliation(s)
- Sara Sanz-Blasco
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
| | - Ruth A. Valero
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
| | - Ignacio Rodríguez-Crespo
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Madrid, Spain
| | - Carlos Villalobos
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
- * E-mail:
| | - Lucía Núñez
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), Valladolid, Spain
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Abstract
The kinetic properties for the uptake, storage and release of Ca2+ from isolated mitochondria accurately predict the behaviour of the organelles within the intact cell. While the steady-state cycling of Ca2+ across the inner membrane between independent uptake and efflux pathways seems at first sight to be symmetrical, the distinctive kinetics of the uniporter, which is highly dependent on external free Ca2+ concentration and the efflux pathway, whose activity is clamped over a wide range of total matrix Ca2+ by the solubility of the calcium phosphate complex provide a mechanism whereby mitochondria reversibly sequester transient elevations in cytoplasmic Ca2+. Under non-stimulated conditions, the same transport processes can regulate matrix Ca2+ concentrations and hence citric acid cycle activity.
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Affiliation(s)
- David G Nicholls
- Buck Institute for Age Research, Redwood Boulevard, Novato, CA 94945, USA.
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Mitochondrial swelling measurement in situ by optimized spatial filtering: astrocyte-neuron differences. Biophys J 2008; 95:2583-98. [PMID: 18424491 DOI: 10.1529/biophysj.107.118620] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Mitochondrial swelling is a hallmark of mitochondrial dysfunction, and is an indicator of the opening of the mitochondrial permeability transition pore. We introduce here a novel quantitative in situ single-cell assay of mitochondrial swelling based on standard wide-field or confocal fluorescence microscopy. This morphometric technique quantifies the relative diameter of mitochondria labeled by targeted fluorescent proteins. Fluorescence micrographs are spatial bandpass filtered transmitting either high or low spatial frequencies. Mitochondrial swelling is measured by the fluorescence intensity ratio of the high- to low-frequency filtered copy of the same image. We have termed this fraction the "thinness ratio". The filters are designed by numeric optimization for sensitivity. We characterized the thinness ratio technique by modeling microscopic image formation and by experimentation in cultured cortical neurons and astrocytes. The frequency domain image processing endows robustness and subresolution sensitivity to the thinness ratio technique, overcoming the limitations of shape measurement approaches. The thinness ratio proved to be highly sensitive to mitochondrial swelling, but insensitive to fission or fusion of mitochondria. We found that in situ astrocytic mitochondria swell upon short-term uncoupling or inhibition of oxidative phosphorylation, whereas such responses are absent in cultured cortical neurons.
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Signoretti S, Marmarou A, Aygok GA, Fatouros PP, Portella G, Bullock RM. Assessment of mitochondrial impairment in traumatic brain injury using high-resolution proton magnetic resonance spectroscopy. J Neurosurg 2008; 108:42-52. [DOI: 10.3171/jns/2008/108/01/0042] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
The goal of this study was to demonstrate the posttraumatic neurochemical damage in normal-appearing brain and to assess mitochondrial dysfunction by measuring N-acetylaspartate (NAA) levels in patients with severe head injuries, using proton (1H) magnetic resonance (MR) spectroscopy.
Methods
Semiquantitative analysis of NAA relative to creatine-containing compounds (Cr) and choline (Cho) was carried out from proton spectra obtained by means of chemical shift (CS) imaging and single-voxel (SV) methods in 25 patients with severe traumatic brain injuries (TBIs) (Glasgow Coma Scale scores ≤ 8) using a 1.5-tesla MR unit. Proton MR spectroscopy was also performed in 5 healthy volunteers (controls).
Results
The SV studies in patients with diffuse TBI showed partial reduction of NAA/Cho and NAA/Cr ratios within the first 10 days after injury (means ± standard deviations 1.59 ± 0.46 and 1.44 ± 0.21, respectively, in the patients compared with 2.08 ± 0.26 and 2.04 ± 0.31, respectively, in the controls; nonsignificant difference). The ratios gradually declined in all patients as time from injury increased (mean minimum values NAA/Cho 1.05 ± 0.44 and NAA/Cr 1.05 ± 0.30, p < 0.03 and p < 0.02, respectively). This reduction was greater in patients with less favorable outcomes. In patients with focal injuries, the periphery of the lesions revealed identical trends of NAA/Cho and NAA/Cr decrease. These reductions correlated with outcome at 6 months (p < 0.01). Assessment with multivoxel methods (CS imaging) demonstrated that, in diffuse injury, NAA levels declined uniformly throughout the brain. At 40 days postinjury, initially low NAA/Cho levels had recovered to near baseline in patients who had good outcomes, whereas no recovery was evident in patients with poor outcomes (p < 0.01).
Conclusions
Using 1H-MR spectroscopy, it is possible to detect the posttraumatic neurochemical damage of the injured brain when conventional neuroimaging techniques reveal no abnormality. Reduction of NAA levels is a dynamic process, evolving over time, decreasing and remaining low throughout the involved tissue in patients with poor outcomes. Recovery of NAA levels in patients with favorable outcomes suggests marginal mitochondrial impairment and possible resynthesis from vital neurons.
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Affiliation(s)
| | | | | | - Panos P. Fatouros
- 2Radiology, Virginia Commonwealth University Medical Center, Richmond, Virginia
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37
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Dendritic and mitochondrial changes during glutamate excitotoxicity. Neuropharmacology 2007; 53:891-8. [DOI: 10.1016/j.neuropharm.2007.10.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2007] [Revised: 09/11/2007] [Accepted: 10/01/2007] [Indexed: 11/18/2022]
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38
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Huser CAM, Davies ME. Calcium signaling leads to mitochondrial depolarization in impact-induced chondrocyte death in equine articular cartilage explants. ACTA ACUST UNITED AC 2007; 56:2322-34. [PMID: 17599752 DOI: 10.1002/art.22717] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE Chondrocyte apoptosis is an important factor in the progression of osteoarthritis. This study aimed to elucidate the mechanisms involved upstream of caspase 9 activation and, in particular, calcium signaling and mitochondrial depolarization. METHODS Articular cartilage explants obtained from healthy horses were subjected to a single impact load (500-gm weight dropped from a height of 50 mm) and cultured in vitro for up to 48 hours. Chondrocyte death was quantified by the TUNEL method. Release of proteoglycans was determined by the dimethylmethylene blue assay. Weight change was measured, and mitochondrial depolarization was determined using JC-1 staining. To assess the role of calcium signaling in impact-induced chondrocyte death, explants were preincubated in culture medium containing various concentrations of calcium. Inhibitors were used to assess the role of individual signaling components in impact-induced chondrocyte death. RESULTS Calcium quenching, inhibitors of calpains, calcium/calmodulin-regulated kinase II (CaMKII), and mitochondrial depolarization reduced impact-induced chondrocyte death after 48 hours in culture. Transient mitochondrial depolarization was observed 3-6 hours following a single impact load. Mitochondrial depolarization was prevented by calcium quenching, inhibitors of calpain, CaMKII, permeability transition pore formation, ryanodine receptor, and the mitochondrial uniport transporter. Cathepsin B did not appear to be involved in impact-induced chondrocyte death. The calpain inhibitor prevented proteoglycan loss, but the percentage weight gain and proteoglycan loss were unaffected by all treatments used. CONCLUSION Following a single impact load, calcium is released from the endoplasmic reticulum via the ryanodine receptor and is taken up by the mitochondria via the uniport transporter, causing mitochondrial depolarization and caspase 9 activation. In addition, calpains and CaMKII play important roles in causing mitochondrial depolarization.
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Norenberg MD, Rao KVR. The mitochondrial permeability transition in neurologic disease. Neurochem Int 2007; 50:983-97. [PMID: 17397969 PMCID: PMC4714712 DOI: 10.1016/j.neuint.2007.02.008] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 02/05/2007] [Accepted: 02/09/2007] [Indexed: 02/06/2023]
Abstract
Mitochondria, being the principal source of cellular energy, are vital for cell life. Yet, ironically, they are also major mediators of cell death, either by necrosis or apoptosis. One means by which these adverse effects occur is through the mitochondrial permeability transition (mPT) whereby the inner mitochondrial membrane suddenly becomes excessively permeable to ions and other solutes, resulting in a collapse of the inner membrane potential, ultimately leading to energy failure and cell necrosis. The mPT may also bring about the release of various factors known to cause apoptotic cell death. The principal factors leading to the mPT are elevated levels of intracellular Ca2+ and oxidative stress. Characteristically, the mPT is inhibited by cyclosporin A. This article will briefly discuss the concept of the mPT, its molecular composition, its inducers and regulators, agents that influence its activity and describe the consequences of its induction. Lastly, we will review its potential contribution to acute neurological disorders, including ischemia, trauma, and toxic-metabolic conditions, as well as its role in chronic neurodegenerative conditions such as Alzheimer's disease, Parkinson's disease, Huntington's disease and amyotrophic lateral sclerosis.
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Affiliation(s)
- M D Norenberg
- Veterans Affairs Medical Center, University of Miami Miller School of Medicine, Miami, FL 33101, USA.
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40
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Li YH, Gong PL. Neuroprotective effect of dauricine in cortical neuron culture exposed to hypoxia and hypoglycemia: involvement of correcting perturbed calcium homeostasis. Can J Physiol Pharmacol 2007; 85:621-7. [PMID: 17823624 DOI: 10.1139/y07-056] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have previously reported that dauricine protects brain tissues from focal cerebral ischemia. To corroborate this effect, neurotoxicity due to hypoxia and hypoglycemia was assessed in primary cultures of rat cortical neurons by using a trypan blue exclusion method. To further clarify the mechanism, the intracellular Ca2+concentration ([Ca2+]i) and mitochondrial membrane potential (ΔΨm) of dissociated rat cortical cells were monitored by fura-2 fluorescence measurements and flow cytometry, respectively. The results showed that 1 and 10 μmol/L dauricine significantly enhanced neuronal survival during 4 h of hypoxia and hypoglycemia. Dauricine inhibited the increase in [Ca2+]iand decrease in ΔΨminduced by 30 min of hypoxia and hypoglycemia. When exploring the pathway, we found that 1 μmol/L dauricine inhibited the [Ca2+]iincrease induced by 7.5 nmol/L thapsigargin in either the presence or absence of extracellular Ca2+and by 1 mmol/L l-glutamate in the presence of extracellular Ca2+. These results suggest that dauricine prevents neuronal loss from ischemia in vitro, which is in accordance with our previous research in vivo. In addition, by inhibiting Ca2+release from the endoplasmic reticulum and Ca2+influx from the extracellular space, dauricine suppressed the increase in [Ca2+]iand, subsequently, the decrease in ΔΨminduced by hypoxia and hypoglycemia. This effect may underlie the mechanism of action of dauricine on cerebral ischemia.
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Affiliation(s)
- Yan-Hong Li
- Department of Pharmacology, Tongji Medical College of Huazhong University of Science and Technology, Wuhan 430030, China
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41
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Shalbuyeva N, Brustovetsky T, Brustovetsky N. Lithium desensitizes brain mitochondria to calcium, antagonizes permeability transition, and diminishes cytochrome C release. J Biol Chem 2007; 282:18057-18068. [PMID: 17485418 DOI: 10.1074/jbc.m702134200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Among the numerous effects of lithium on intracellular targets, its possible action on mitochondria remains poorly explored. In the experiments with suspension of isolated brain mitochondria, replacement of KCl by LiCl suppressed mitochondrial swelling, depolarization, and a release of cytochrome c induced by a single Ca2+ bolus. Li+ robustly protected individual brain mitochondria loaded with rhodamine 123 against Ca2+-induced depolarization. In the experiments with slow calcium infusion, replacement of KCl by LiCl in the incubation medium increased resilience of synaptic and nonsynaptic brain mitochondria as well as resilience of liver and heart mitochondria to the deleterious effect of Ca2+. In LiCl medium, mitochondria accumulated larger amounts of Ca2+ before they lost the ability to sequester Ca2+. However, lithium appeared to be ineffective if mitochondria were challenged by Sr2+ instead of Ca2+. Cyclosporin A, sanglifehrin A, and Mg2+, inhibitors of the mitochondrial permeability transition (mPT), increased mitochondrial Ca2+ capacity in KCl medium but failed to do so in LiCl medium. This suggests that the mPT might be a common target for Li+ and mPT inhibitors. In addition, lithium protected mitochondria against high Ca2+ in the presence of ATP, where cyclosporin A was reported to be ineffective. SB216763 and SB415286, inhibitors of glycogen synthase kinase-3beta, which is implicated in regulating reactive oxygen species-induced mPT in cardiac mitochondria, did not increase Ca2+ capacity of brain mitochondria. Altogether, these findings suggest that Li+ desensitizes mitochondria to elevated Ca2+ and diminishes cytochrome c release from brain mitochondria by antagonizing the Ca2+-induced mPT.
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Affiliation(s)
- Natalia Shalbuyeva
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Tatiana Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Nickolay Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana 46202; Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202.
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Marino S, Marani L, Nazzaro C, Beani L, Siniscalchi A. Mechanisms of sodium azide-induced changes in intracellular calcium concentration in rat primary cortical neurons. Neurotoxicology 2007; 28:622-9. [PMID: 17316809 DOI: 10.1016/j.neuro.2007.01.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Revised: 11/21/2006] [Accepted: 01/15/2007] [Indexed: 11/28/2022]
Abstract
An intracellular calcium ([Ca(2+)](i)) increase is involved in sodium azide (NaN(3))-induced neurotoxicity, an in vitro model of brain ischemia. In this study the questions of possible additional sources of calcium influx, besides glutamate receptor activation, and of the time-course of NaN(3) effects have been addressed by measuring [Ca(2+)](i) in rat primary cortical cultures with the FURA-2 method. Basal [Ca(2+)](i) of neuronal populations was concentration-dependently increased 30 min, but not 24h, after a 10-min NaN(3) (3-30 mM) treatment; conversely, the net increase induced by electrical stimulation (10Hz, 10s) was consistently reduced. All the above effects depended on glutamate release and consequent NMDA receptor activation, since the NMDA antagonist MK-801 (1 microM) prevented them, and the spontaneous efflux of [(3)H]-d-aspartate from superfused neurons was concentration-dependently increased by NaN(3). In single neuronal cells, NaN(3) application progressively and concentration-dependently increased [Ca(2+)](i) (to 177+/-5% and 249+/-7% of the controls, 4 and 12 min after a 10mM-treatment, respectively). EGTA (5mM) pretreatment reduced the effect of 10mM NaN(3) (to 118+/-5% at 4 min, and to 148+/-10% at 12 min, respectively), while 1 microM cyclosporin A did not. Both MK-801 and CNQX (a non-NMDA glutamate antagonist, 10 microM) prevented NaN(3) effect at 4 min (to 147+/-8% and 153+/-5%, respectively), but not at 12 min after NaN(3) treatment. Conversely, 10 microM verapamil and 0.1 microM omega-conotoxin (L- and N-type calcium channel blockers, respectively) significantly attenuated NaN(3) effects at 12 min (to 198+/-8% and 164+/-5%, respectively), but not at 4 min; the P/Q-type calcium channel blocker, agatoxin, 0.3 microM, was ineffective. These findings show that the predominant source of calcium increase induced by NaN(3) is extracellular, involving glutamate receptor activation in a first step and calcium channel (mainly of the N-type) opening in a second step.
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Affiliation(s)
- Silvia Marino
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Ferrara, Via Fossato di Mortara 17-19, 44100 Ferrara, Italy
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Bantseev V, Youn HY. Mitochondrial "movement" and lens optics following oxidative stress from UV-B irradiation: cultured bovine lenses and human retinal pigment epithelial cells (ARPE-19) as examples. Ann N Y Acad Sci 2007; 1091:17-33. [PMID: 17341599 DOI: 10.1196/annals.1378.051] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mitochondria provide energy generated by oxidative phosphorylation and at the same time play a central role in apoptosis and aging. As a byproduct of respiration, the electron transport chain is known to be the major intracellular site for the generation of reactive oxygen species (ROS). Exposure to solar and occupational ultraviolet (UV) radiation, and thus production of ROS and subsequent cell death, has been implicated in a large spectrum of skin and ocular pathologies, including cataract. Retinal pigment epithelial cell apoptosis generates photoreceptor dysfunction and ultimately visual impairment. The purpose of this article was to characterize in vitro changes following oxidative stress with UV-B radiation in (a) ocular lens optics and cellular function in terms of mitochondrial dynamics of bovine lens epithelium and superficial cortical fiber cells and (b) human retinal pigment epithelial (ARPE-19) cells. Cultured bovine lenses and confluent cultures of ARPE-19 cells were irradiated with broadband UV-B radiation at energy levels of 0.5 and 1.0 J/cm(2). Lens optical function (spherical aberration) was monitored daily up to 14 days using an automated laser scanning system that was developed at the University of Waterloo. This system consists of a single collimated scanning helium-neon laser source that projects a thin (0.05 mm) laser beam onto a plain mirror mounted at 45 degrees on a carriage assembly. This mirror reflects the laser beam directly up through the scanner table surface and through the lens under examination. A digital camera captures the actual position and slope of the laser beam at each step. When all steps have been made, the captured data for each step position is used to calculate the back vertex distance for each position and the difference in that measurement between beams. To investigate mitochondrial movement, the mitochondria-specific fluorescent dye Rhodamine 123 was used. Time series were acquired with a Zeiss 510 (configuration Meta 18) confocal laser scanning microscope equipped with an inverted Axiovert 200 M microscope and 40-x water-immersion C-Apochromat objective (NA 1.2). The optical analysis showed energy level-dependent increases in back vertex distance variability (loss of sharp focus) from 0.39 +/- 0.04 mm (control, n = 11) to 1.63 +/- 0.33 mm (1.0 J/cm(2), n = 10) and 0.63 +/- 0.13 mm (0.5 J/cm(2), n = 9). Confocal laser scanning microscopy analysis of both bovine lenses and ARPE-19 cells showed that following treatment at 0.5 J/cm(2) the mitochondria stopped moving immediately whereas at 1.0 J/cm(2) not only did the mitochondria stop moving, but fragmentation and swelling was seen. Untreated control tissue exhibited up to 15 microm/min of movement of the mitochondria. This could represent normal morphological change, presumably allowing energy transmission across the cell from regions of low to regions of high ATP demand. Lack of mitochondrial movement, fragmentation, and swelling of mitochondria may represent early morphological changes following oxidative stress that may lead to activation of caspase-mediated apoptotic pathways.
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Affiliation(s)
- Vladimir Bantseev
- School of Optometry, University of Waterloo, Waterloo, Ontario N2L 3G1 Canada.
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Shalbuyeva N, Brustovetsky T, Bolshakov A, Brustovetsky N. Calcium-dependent spontaneously reversible remodeling of brain mitochondria. J Biol Chem 2006; 281:37547-58. [PMID: 17056496 DOI: 10.1074/jbc.m607263200] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An exposure of cultured hippocampal neurons expressing mitochondrially targeted enhanced yellow fluorescent protein to excitotoxic glutamate resulted in reversible mitochondrial remodeling that in many instances could be interpreted as swelling. Remodeling was not evident if glutamate receptors were blocked with MK801, if Ca(2+) was omitted or substituted for Sr(2+) in the bath solution, if neurons were treated with carbonylcyanide p-trifluoromethoxyphenylhydrazone to depolarize mitochondria, or if neurons were pretreated with cyclosporin A or N-methyl-4-isoleucine-cyclosporin (NIM811) to inhibit the mitochondrial permeability transition. In the experiments with isolated brain synaptic or nonsynaptic mitochondria, Ca(2+) triggered transient, spontaneously reversible cyclosporin A-sensitive swelling closely resembling remodeling of organelles in cultured neurons. The swelling was accompanied by the release of cytochrome c, Smac/DIABLO, Omi/HtrA2, and AIF but not endonuclease G. Depolarization with carbonylcyanide p-trifluoromethoxyphenylhydrazone or inhibition of the Ca(2+) uniporter with Ru360 prevented rapid onset of the swelling. Sr(2+) depolarized mitochondria but failed to induce swelling. Neither inhibitors of the large conductance Ca(2+)-activated K(+) channel (charybdotoxin, iberiotoxin, quinine, and Ba(2+)) nor inhibitors of the mitochondrial ATP-sensitive K(+) channel (5-hydroxydecanoate and glibenclamide) suppressed swelling. Quinine, dicyclohexylcarbodiimide, and Mg(2+), inhibitors of the mitochondrial K(+)/H(+) exchanger, as well as external alkalization inhibited a recovery phase of the reversible swelling. In contrast to brain mitochondria, liver and heart mitochondria challenged with Ca(2+) experienced sustained swelling without spontaneous recovery. The proposed model suggests an involvement of the Ca(2+)-dependent transient K(+) influx into the matrix causing mitochondrial swelling followed by activation of the K(+)/H(+) exchanger leading to spontaneous mitochondrial contraction both in situ and in vitro.
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Affiliation(s)
- Natalia Shalbuyeva
- Department of Pharmacology and Toxicology, Stark Neuroscience Research Institute, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
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45
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Bambrick LL, Chandrasekaran K, Mehrabian Z, Wright C, Krueger BK, Fiskum G. Cyclosporin A increases mitochondrial calcium uptake capacity in cortical astrocytes but not cerebellar granule neurons. J Bioenerg Biomembr 2006; 38:43-7. [PMID: 16786428 PMCID: PMC2570318 DOI: 10.1007/s10863-006-9004-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Isolated brain mitochondria are a heterogeneous mixture from different cell types and these subsets may have differing sensitivities to Ca2+-induced membrane permeability transition (MPT) and to inhibition of the MPT by cyclosporin A (CsA). This study tested the hypothesis that mitochondria within primary cultures of astrocytes and neurons exhibit different energy-dependent Ca2+ uptake capacities and different degrees to which CsA increases their uptake capacity. Astrocytes and neurons were suspended in a cytosol-like medium containing respiratory substrates, ATP, and Mg2+ in the presence of digitonin to selectively permeabilize the plasma membrane. Uptake of added Ca2+ by mitochondria within the cells was measured by Calcium Green 5N fluorescent monitoring of the medium [Ca2+]. Permeabilized astrocytes had a fourfold higher Ca2+ uptake capacity, relative to neurons and a twofold higher content based on relative contents of mitochondria assessed by measurements of mitochondrial DNA and cytochrome oxidase subunit 1 protein. In astrocytes the Ca2+ uptake capacity was increased twofold by preincubation with 2-5 microM CsA, while in neurons CsA had no effect. Similar results were obtained using measurements of the effects of added Ca2+ on mitochondrial membrane potential. FK506, a drug similar to CsA but without MPT inhibitory activity, had no effect on either cell type. These results are consistent with the presence of a calcium-induced MPT in astrocytes, even in the presence of ATP, and indicate that the MPT in cerebellar granule neurons is resistant to CsA inhibition. Some of the protective effects of CsA in vivo may therefore be mediated by preservation of mitochondrial functional integrity within astrocytes.
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Affiliation(s)
- Linda L Bambrick
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
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46
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Nicholls DG. Simultaneous monitoring of ionophore- and inhibitor-mediated plasma and mitochondrial membrane potential changes in cultured neurons. J Biol Chem 2006; 281:14864-74. [PMID: 16551630 DOI: 10.1074/jbc.m510916200] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although natural and synthetic ionophores are widely exploited in cell studies, for example, to influence cytoplasmic free calcium concentrations and to depolarize in situ mitochondria, their inherent lack of membrane selectivity means that they affect the ion permeability of both plasma and mitochondrial membranes. A similar ambiguity affects the interpretation of signals from fluorescent membrane-permeant cations (usually termed "mitochondrial membrane potential indicators"), because the accumulation of these probes is influenced by both plasma and mitochondrial membrane potentials. To resolve some of these problems a technique is developed to allow simultaneous monitoring of plasma and mitochondrial membrane potentials at single-cell resolution using a cationic and anionic fluorescent probe. A computer program is described that transforms the fluorescence changes into dynamic estimates of changes in plasma and mitochondrial potentials. Exploiting this technique, primary cultures of rat cerebellar granule neurons display a concentration-dependent response to ionomycin: low concentrations mimic nigericin by hyperpolarizing the mitochondria while slowly depolarizing the plasma membrane and maintaining a stable elevated cytoplasmic calcium. Higher ionomycin concentrations induce a stochastic failure of calcium homeostasis that precedes both mitochondrial depolarization and an enhanced rate of plasma membrane depolarization. In addition, the protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone only selectively depolarizes mitochondria at submicromolar concentrations. ATP synthase reversal following respiratory chain inhibition depolarizes the mitochondria by 26 mV.
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Affiliation(s)
- David G Nicholls
- Buck Institute for Age Research, 8001 Redwood Boulevard, Novato, CA 94945, USA.
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47
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Chinopoulos C, Adam-Vizi V. Calcium, mitochondria and oxidative stress in neuronal pathology. Novel aspects of an enduring theme. FEBS J 2006; 273:433-50. [PMID: 16420469 DOI: 10.1111/j.1742-4658.2005.05103.x] [Citation(s) in RCA: 170] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The interplay among reactive oxygen species (ROS) formation, elevated intracellular calcium concentration and mitochondrial demise is a recurring theme in research focusing on brain pathology, both for acute and chronic neurodegenerative states. However, causality, extent of contribution or the sequence of these events prior to cell death is not yet firmly established. Here we review the role of the alpha-ketoglutarate dehydrogenase complex as a newly identified source of mitochondrial ROS production. Furthermore, based on contemporary reports we examine novel concepts as potential mediators of neuronal injury connecting mitochondria, increased [Ca2+]c and ROS/reactive nitrogen species (RNS) formation; specifically: (a) the possibility that plasmalemmal nonselective cationic channels contribute to the latent [Ca2+]c rise in the context of glutamate-induced delayed calcium deregulation; (b) the likelihood of the involvement of the channels in the phenomenon of 'Ca2+ paradox' that might be implicated in ischemia/reperfusion injury; and (c) how ROS/RNS and mitochondrial status could influence the activity of these channels leading to loss of ionic homeostasis and cell death.
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Affiliation(s)
- Christos Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Neurobiochemical Group, Hungarian Academy of Sciences, Szentagothai Knowledge Center, Budapest, Hungary
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48
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Abstract
Three routes have been identified triggering neuronal death under physiological and pathological conditions. Excess activation of ionotropic glutamate receptors cause influx and accumulation of Ca2+ and Na+ that result in rapid swelling and subsequent neuronal death within a few hours. The second route is caused by oxidative stress due to accumulation of reactive oxygen and nitrogen species. Apoptosis or programmed cell death that often occurs during developmental process has been coined as additional route to pathological neuronal death in the mature nervous system. Evidence is being accumulated that excitotoxicity, oxidative stress, and apoptosis propagate through distinctive and mutually exclusive signal transduction pathway and contribute to neuronal loss following hypoxic-ischemic brain injury. Thus, the therapeutic intervention of hypoxic-ischemic neuronal injury should be aimed to prevent excitotoxicity, oxidative stress, and apoptosis in a concerted way.
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Affiliation(s)
- Seok Joon Won
- Center for the Interventional Therapy of Stroke and Alzheimers Disease, Department of Pharmacology, Ajou University School of Medicine, San 5, Wonchondong, Paldalgu, Suwon, Kyungkido 442-749, South Korea
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49
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Hino K, Nishikawa M, Sato E, Inoue M. L-carnitine inhibits hypoglycemia-induced brain damage in the rat. Brain Res 2005; 1053:77-87. [PMID: 16051203 DOI: 10.1016/j.brainres.2005.06.062] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Revised: 06/09/2005] [Accepted: 06/10/2005] [Indexed: 11/28/2022]
Abstract
Hypoglycemia sometimes occurs in patients with diabetes mellitus who receive excessive doses of insulin. Severe hypoglycemia has been known to induce mitochondrial swelling followed by neuronal death in the brain. Since L-carnitine effectively preserves mitochondrial function in various cells both in vitro and in vivo, we investigated its effects on the neuronal damage induced by hypoglycemic insult in male Wistar rats. Animals were given L-carnitine-containing water (0.1%) for 1 week and then received insulin (20 U/kg, i.p.) to induce hypoglycemia. Although L-carnitine did not affect the mortality of animals that developed hypoglycemic shock, it improved the cognitive function of the survived animals as assessed by the Morris water-maze test. L-carnitine effectively inhibited the increase in oxidized glutathione and mitochondrial dysfunction in the hippocampus and prevented neuronal injury. L-carnitine also inhibited the decrease in mitochondrial membrane potential and the generation of reactive oxygen species in hippocampal neuronal cells cultured in glucose-deprived medium. These results suggest that L-carnitine prevents hypoglycemia-induced neuronal damage in the hippocampus, presumably by preserving mitochondrial functions. Thus, L-carnitine may have therapeutic potential in patients with hypoglycemia induced by insulin overdose.
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Affiliation(s)
- Kazuo Hino
- Department of Biochemistry and Molecular Pathology, Osaka City University Medical School, Osaka 545-8586, Japan
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50
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Scheffler IE. A century of mitochondrial research: achievements and perspectives. Mitochondrion 2005; 1:3-31. [PMID: 16120266 DOI: 10.1016/s1567-7249(00)00002-7] [Citation(s) in RCA: 167] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- I E Scheffler
- Division of Biology, University of California, San Diego, and Center for Molecular Genetics, La Jolla, CA 92093-0322, USA.
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