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Pisani F, Pisani V, Arcangeli F, Harding A, Singhrao SK. Treponema denticola Has the Potential to Cause Neurodegeneration in the Midbrain via the Periodontal Route of Infection-Narrative Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:6049. [PMID: 37297653 PMCID: PMC10252855 DOI: 10.3390/ijerph20116049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2023] [Revised: 03/30/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease and the most common example of dementia. The neuropathological features of AD are the abnormal deposition of extracellular amyloid-β (Aβ) and intraneuronal neurofibrillary tangles with hyperphosphorylated tau protein. It is recognized that AD starts in the frontal cerebral cortex, and then it progresses to the entorhinal cortex, the hippocampus, and the rest of the brain. However, some studies on animals suggest that AD could also progress in the reverse order starting from the midbrain and then spreading to the frontal cortex. Spirochetes are neurotrophic: From a peripheral route of infection, they can reach the brain via the midbrain. Their direct and indirect effect via the interaction of their virulence factors and the microglia potentially leads to the host peripheral nerve, the midbrain (especially the locus coeruleus), and cortical damage. On this basis, this review aims to discuss the hypothesis of the ability of Treponema denticola to damage the peripheral axons in the periodontal ligament, to evade the complemental pathway and microglial immune response, to determine the cytoskeletal impairment and therefore causing the axonal transport disruption, an altered mitochondrial migration and the consequent neuronal apoptosis. Further insights about the central neurodegeneration mechanism and Treponema denticola's resistance to the immune response when aggregated in biofilm and its quorum sensing are suggested as a pathogenetic model for the advanced stages of AD.
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Affiliation(s)
- Flavio Pisani
- Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - Valerio Pisani
- IRCCS, “Santa Lucia” Foundation, Neurology and Neurorehabilitation Unit, Via Ardeatina, 306, 00179 Rome, Italy
| | - Francesca Arcangeli
- Azienda Sanitaria Locale ASLRM1, Nuovo Regina Margherita Hospital, Geriatric Department, Advanced Centre for Dementia and Cognitive Disorders, Via Emilio Morosini, 30, 00153 Rome, Italy
| | - Alice Harding
- Dementia and Neurodegenerative Disease Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
| | - Simarjit Kaur Singhrao
- Dementia and Neurodegenerative Disease Research Group, Faculty of Clinical and Biomedical Sciences, School of Dentistry, University of Central Lancashire, Preston PR1 2HE, UK
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Mencel ML, Bittner GD. Repair of traumatic lesions to the plasmalemma of neurons and other cells: Commonalities, conflicts, and controversies. Front Physiol 2023; 14:1114779. [PMID: 37008019 PMCID: PMC10050709 DOI: 10.3389/fphys.2023.1114779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 02/14/2023] [Indexed: 03/17/2023] Open
Abstract
Neuroscientists and Cell Biologists have known for many decades that eukaryotic cells, including neurons, are surrounded by a plasmalemma/axolemma consisting of a phospholipid bilayer that regulates trans-membrane diffusion of ions (including calcium) and other substances. Cells often incur plasmalemmal damage via traumatic injury and various diseases. If the damaged plasmalemma is not rapidly repaired within minutes, activation of apoptotic pathways by calcium influx often results in cell death. We review publications reporting what is less-well known (and not yet covered in neuroscience or cell biology textbooks): that calcium influx at the lesion sites ranging from small nm-sized holes to complete axonal transection activates parallel biochemical pathways that induce vesicles/membrane-bound structures to migrate and interact to restore original barrier properties and eventual reestablishment of the plasmalemma. We assess the reliability of, and problems with, various measures (e.g., membrane voltage, input resistance, current flow, tracer dyes, confocal microscopy, transmission and scanning electron microscopy) used individually and in combination to assess plasmalemmal sealing in various cell types (e.g., invertebrate giant axons, oocytes, hippocampal and other mammalian neurons). We identify controversies such as plug versus patch hypotheses that attempt to account for currently available data on the subcellular mechanisms of plasmalemmal repair/sealing. We describe current research gaps and potential future developments, such as much more extensive correlations of biochemical/biophysical measures with sub-cellular micromorphology. We compare and contrast naturally occurring sealing with recently-discovered artificially-induced plasmalemmal sealing by polyethylene glycol (PEG) that bypasses all natural pathways for membrane repair. We assess other recent developments such as adaptive membrane responses in neighboring cells following injury to an adjacent cell. Finally, we speculate how a better understanding of the mechanisms involved in natural and artificial plasmalemmal sealing is needed to develop better clinical treatments for muscular dystrophies, stroke and other ischemic conditions, and various cancers.
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Affiliation(s)
- Marshal L. Mencel
- Institute of Cell and Molecular Biology, University of Texas at Austin, Austin, TX, United States
| | - George D. Bittner
- Department of Neuroscience, University of Texas at Austin, Austin, TX, United States
- *Correspondence: George D. Bittner,
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Hiengrach P, Visitchanakun P, Tongchairawewat P, Tangsirisatian P, Jungteerapanich T, Ritprajak P, Wannigama DL, Tangtanatakul P, Leelahavanichkul A. Sepsis Encephalopathy Is Partly Mediated by miR370-3p-Induced Mitochondrial Injury but Attenuated by BAM15 in Cecal Ligation and Puncture Sepsis Male Mice. Int J Mol Sci 2022; 23:ijms23105445. [PMID: 35628259 PMCID: PMC9141734 DOI: 10.3390/ijms23105445] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 02/06/2023] Open
Abstract
BAM15 (a mitochondrial uncoupling agent) was tested on cecal ligation and puncture (CLP) sepsis mice with in vitro experiments. BAM15 attenuated sepsis as indicated by survival, organ histology (kidneys and livers), spleen apoptosis (activated caspase 3), brain injury (SHIRPA score, serum s100β, serum miR370-3p, brain miR370-3p, brain TNF-α, and apoptosis), systemic inflammation (cytokines, cell-free DNA, endotoxemia, and bacteremia), and blood-brain barrier (BBB) damage (Evan's blue dye and the presence of green fluorescent E. coli in brain after an oral administration). In parallel, brain miR arrays demonstrated miR370-3p at 24 h but not 120 h post-CLP, which was correlated with metabolic pathways. Either lipopolysaccharide (LPS) or TNF-α upregulated miR370-3p in PC12 (neuron cells). An activation by sepsis factors (LPS, TNF-α, or miR370-3p transfection) damaged mitochondria (fluorescent color staining) and reduced cell ATP, possibly through profound mitochondrial activity (extracellular flux analysis) that was attenuated by BAM15. In bone-marrow-derived macrophages, LPS caused mitochondrial injury, decreased cell ATP, enhanced glycolysis activity (extracellular flux analysis), and induced pro-inflammatory macrophages (iNOS and IL-1β) which were neutralized by BAM15. In conclusion, BAM15 attenuated sepsis through decreased mitochondrial damage, reduced neuronal miR370-3p upregulation, and induced anti-inflammatory macrophages. BAM15 is proposed to be used as an adjuvant therapy against sepsis hyperinflammation.
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Affiliation(s)
- Pratsanee Hiengrach
- Center of Excellence on Translational Research in Inflammation and Immunology (CETRII), Department of Microbiology, Chulalongkorn University, Bangkok 10330, Thailand; (P.H.); (P.V.)
| | - Peerapat Visitchanakun
- Center of Excellence on Translational Research in Inflammation and Immunology (CETRII), Department of Microbiology, Chulalongkorn University, Bangkok 10330, Thailand; (P.H.); (P.V.)
| | - Pakteema Tongchairawewat
- Chulalongkorn University International Medical Program, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand; (P.T.); (P.T.); (T.J.)
| | - Ponphisudti Tangsirisatian
- Chulalongkorn University International Medical Program, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand; (P.T.); (P.T.); (T.J.)
| | - Thitiphat Jungteerapanich
- Chulalongkorn University International Medical Program, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand; (P.T.); (P.T.); (T.J.)
| | - Patcharee Ritprajak
- Research Unit in Integrative Immuno-Microbial Biochemistry and Bioresponsive Nanomaterials, Department of Microbiology, Faculty of Dentistry, Chulalongkorn University, Bangkok 10330, Thailand;
| | - Dhammika Leshan Wannigama
- Antimicrobial Resistance and Stewardship Research Unit, Department of Microbiology, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand;
- School of Medicine, Faculty of Health and Medical Sciences, The University of Western Australia, Nedlands, WA 6009, Australia
| | - Pattarin Tangtanatakul
- Department of Transfusion Medicine and Clinical Microbiology, Faculty of Allied Health Sciences, Chulalongkorn University, Bangkok 10330, Thailand
- Center of Excellence in Immunology and Immune-Mediated Disease, Department of Microbiology, Chulalongkorn University, Bangkok 10330, Thailand
- Correspondence: (P.T.); (A.L.); Tel.: +66-2256-4132 (A.L.); Fax: +66-2252-5952 (A.L.)
| | - Asada Leelahavanichkul
- Center of Excellence on Translational Research in Inflammation and Immunology (CETRII), Department of Microbiology, Chulalongkorn University, Bangkok 10330, Thailand; (P.H.); (P.V.)
- Nephrology Unit, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
- Correspondence: (P.T.); (A.L.); Tel.: +66-2256-4132 (A.L.); Fax: +66-2252-5952 (A.L.)
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Tjiang N, Zempel H. A mitochondria cluster at the proximal axon initial segment controls axodendritic TAU trafficking in rodent primary and human iPSC-derived neurons. Cell Mol Life Sci 2022; 79:120. [PMID: 35119496 PMCID: PMC8816743 DOI: 10.1007/s00018-022-04150-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 12/30/2021] [Accepted: 01/14/2022] [Indexed: 12/23/2022]
Abstract
Loss of neuronal polarity and missorting of the axonal microtubule-associated-protein TAU are hallmarks of Alzheimer’s disease (AD) and related tauopathies. Impairment of mitochondrial function is causative for various mitochondriopathies, but the role of mitochondria in tauopathies and in axonal TAU-sorting is unclear. The axon-initial-segment (AIS) is vital for maintaining neuronal polarity, action potential generation, and—here important—TAU-sorting. Here, we investigate the role of mitochondria in the AIS for maintenance of TAU cellular polarity. Using not only global and local mitochondria impairment via inhibitors of the respiratory chain and a locally activatable protonophore/uncoupler, but also live-cell-imaging and photoconversion methods, we specifically tracked and selectively impaired mitochondria in the AIS in primary mouse and human iPSC-derived forebrain/cortical neurons, and assessed somatic presence of TAU. Global application of mitochondrial toxins efficiently induced tauopathy-like TAU-missorting, indicating involvement of mitochondria in TAU-polarity. Mitochondria show a biased distribution within the AIS, with a proximal cluster and relative absence in the central AIS. The mitochondria of this cluster are largely immobile and only sparsely participate in axonal mitochondria-trafficking. Locally constricted impairment of the AIS-mitochondria-cluster leads to detectable increases of somatic TAU, reminiscent of AD-like TAU-missorting. Mechanistically, mitochondrial impairment sufficient to induce TAU-missorting results in decreases of calcium oscillation but increases in baseline calcium, yet chelating intracellular calcium did not prevent mitochondrial impairment-induced TAU-missorting. Stabilizing microtubules via taxol prevented TAU-missorting, hinting towards a role for impaired microtubule dynamics in mitochondrial-dysfunction-induced TAU-missorting. We provide evidence that the mitochondrial distribution within the proximal axon is biased towards the proximal AIS and that proper function of this newly described mitochondrial cluster may be essential for the maintenance of TAU polarity. Mitochondrial impairment may be an upstream event in and therapeutic target for AD/tauopathy.
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Affiliation(s)
- Noah Tjiang
- Institute of Human Genetics, Faculty of Medicine, University Hospital Cologne, University of Cologne, 50931, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine, University Hospital Cologne, University of Cologne, 50931, Cologne, Germany
| | - Hans Zempel
- Institute of Human Genetics, Faculty of Medicine, University Hospital Cologne, University of Cologne, 50931, Cologne, Germany. .,Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine, University Hospital Cologne, University of Cologne, 50931, Cologne, Germany.
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5
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English K, Barton MC. HDAC6: A Key Link Between Mitochondria and Development of Peripheral Neuropathy. Front Mol Neurosci 2021; 14:684714. [PMID: 34531721 PMCID: PMC8438325 DOI: 10.3389/fnmol.2021.684714] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 07/30/2021] [Indexed: 01/21/2023] Open
Abstract
Peripheral neuropathy, which is the result of nerve damage from lesions or disease, continues to be a major health concern due to the common manifestation of neuropathic pain. Most investigations into the development of peripheral neuropathy focus on key players such as voltage-gated ion channels or glutamate receptors. However, emerging evidence points to mitochondrial dysfunction as a major player in the development of peripheral neuropathy and resulting neuropathic pain. Mitochondrial dysfunction in neuropathy includes altered mitochondrial transport, mitochondrial metabolism, as well as mitochondrial dynamics. The mechanisms that lead to mitochondrial dysfunction in peripheral neuropathy are poorly understood, however, the Class IIb histone deacetylase (HDAC6), may play an important role in the process. HDAC6 is a key regulator in multiple mechanisms of mitochondrial dynamics and may contribute to mitochondrial dysregulation in peripheral neuropathy. Accumulating evidence shows that HDAC6 inhibition is strongly associated with alleviating peripheral neuropathy and neuropathic pain, as well as mitochondrial dysfunction, in in vivo and in vitro models of peripheral neuropathy. Thus, HDAC6 inhibitors are being investigated as potential therapies for multiple peripheral neuropathic disorders. Here, we review emerging studies and integrate recent advances in understanding the unique connection between peripheral neuropathy and mitochondrial dysfunction through HDAC6-mediated interactions.
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Affiliation(s)
- Krystal English
- UTHealth Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
- UTHealth McGovern Medical School, Houston, TX, United States
| | - Michelle Craig Barton
- UTHealth Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
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6
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Al Rahim M, Thatipamula S, Pasinetti GM, Hossain MA. Neuronal Pentraxin 1 Promotes Hypoxic-Ischemic Neuronal Injury by Impairing Mitochondrial Biogenesis via Interactions With Active Bax[6A7] and Mitochondrial Hexokinase II. ASN Neuro 2021; 13:17590914211012888. [PMID: 34098747 PMCID: PMC8191073 DOI: 10.1177/17590914211012888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Mitochondrial dysfunction is a key mechanism of cell death in hypoxic-ischemic brain injury. Neuronal pentraxin 1 (NP1) has been shown to play crucial roles in mitochondria-mediated neuronal death. However, the underlying mechanism(s) of NP1-induced mitochondrial dysfunction in hypoxia-ischemia (HI) remains obscure. Here, we report that NP1 induction following HI and its subsequent localization to mitochondria, leads to disruption of key regulatory proteins for mitochondrial biogenesis. Brain mitochondrial DNA (mtDNA) content and mtDNA-encoded subunit I of complex IV (mtCOX-1) expression was increased post-HI, but not the nuclear DNA-encoded subunit of complex II (nSDH-A). Up-regulation of mitochondrial proteins COXIV and HSP60 further supported enhanced mtDNA function. NP1 interaction with active Bax (Bax6A7) was increased in the brain after HI and in oxygen-glucose deprivation (OGD)-induced neuronal cultures. Importantly, NP1 colocalized with mitochondrial hexokinase II (mtHKII) following OGD leading to HKII dissociation from mitochondria. Knockdown of NP1 or SB216763, a GSK-3 inhibitor, prevented OGD-induced mtHKII dissociation and cellular ATP decrease. NP1 also modulated the expression of mitochondrial transcription factor A (Tfam) and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), regulators of mitochondrial biogenesis, following HI. Together, we reveal crucial roles of NP1 in mitochondrial biogenesis involving interactions with Bax[6A7] and mtHKII in HI brain injury.
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Affiliation(s)
- Md Al Rahim
- Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States.,Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York, United States
| | - Shabarish Thatipamula
- Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Giulio M Pasinetti
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York, United States.,James J. Peters Veterans Affairs Medical Center, Bronx, New York, United States
| | - Mir Ahamed Hossain
- Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, United States.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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7
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Hong JY, Kim H, Lee J, Jeon WJ, Baek SH, Ha IH. Neurotherapeutic Effect of Inula britannica var. Chinensis against H 2O 2-Induced Oxidative Stress and Mitochondrial Dysfunction in Cortical Neurons. Antioxidants (Basel) 2021; 10:antiox10030375. [PMID: 33802485 PMCID: PMC8001496 DOI: 10.3390/antiox10030375] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/14/2021] [Accepted: 02/23/2021] [Indexed: 12/06/2022] Open
Abstract
Inula britannica var. chinensis (IBC) has been used as a traditional medicinal herb to treat inflammatory diseases. Although its anti-inflammatory and anti-oxidative effects have been reported, whether IBC exerts neuroprotective effects and the related mechanisms in cortical neurons remain unknown. In this study, we investigated the effects of different concentrations of IBC extract (5, 10, and 20 µg/mL) on cortical neurons using a hydrogen peroxide (H2O2)-induced injury model. Our results demonstrate that IBC can effectively enhance neuronal viability under in vitro-modeled reaction oxygen species (ROS)-generating conditions by inhibiting mitochondrial ROS production and increasing adenosine triphosphate level in H2O2-treated neurons. Additionally, we confirmed that neuronal death was attenuated by improving the mitochondrial membrane potential status and regulating the expression of cytochrome c, a protein related to cell death. Furthermore, IBC increased the expression of brain-derived neurotrophic factor and nerve growth factor. Furthermore, IBC inhibited the loss and induced the production of synaptophysin, a major synaptic vesicle protein. This study is the first to demonstrate that IBC exerts its neuroprotective effect by reducing mitochondria-associated oxidative stress and improving mitochondrial dysfunction.
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Affiliation(s)
- Jin Young Hong
- Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul 135-896, Korea; (J.Y.H.); (H.K.); (J.L.); (W.-J.J.)
| | - Hyunseong Kim
- Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul 135-896, Korea; (J.Y.H.); (H.K.); (J.L.); (W.-J.J.)
| | - Junseon Lee
- Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul 135-896, Korea; (J.Y.H.); (H.K.); (J.L.); (W.-J.J.)
| | - Wan-Jin Jeon
- Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul 135-896, Korea; (J.Y.H.); (H.K.); (J.L.); (W.-J.J.)
| | - Seung Ho Baek
- College of Korean Medicine, Dongguk University, 32 Dongguk-ro, Ilsandong-gu, Goyang-si 10326, Korea;
| | - In-Hyuk Ha
- Jaseng Spine and Joint Research Institute, Jaseng Medical Foundation, Seoul 135-896, Korea; (J.Y.H.); (H.K.); (J.L.); (W.-J.J.)
- Correspondence: ; Tel.: +82-2-2222-2740; Fax: +82-2-527-1869
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8
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Calkins DJ. Adaptive responses to neurodegenerative stress in glaucoma. Prog Retin Eye Res 2021; 84:100953. [PMID: 33640464 DOI: 10.1016/j.preteyeres.2021.100953] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/08/2021] [Accepted: 02/19/2021] [Indexed: 12/12/2022]
Abstract
Glaucoma causes loss of vision through degeneration of the retinal ganglion cell (RGC) projection to the brain. The disease is characterized by sensitivity to intraocular pressure (IOP) conveyed at the optic nerve head, through which RGC axons pass unmyelinated to form the optic nerve. From this point, a pathogenic triumvirate comprising inflammatory, oxidative, and metabolic stress influence both proximal structures in the retina and distal structures in the optic projection. This review focuses on metabolic stress and how the optic projection may compensate through novel adaptive mechanisms to protect excitatory signaling to the brain. In the retina and proximal nerve head, the unmyelinated RGC axon segment is energy-inefficient, which leads to increased demand for adenosine-5'-triphosphate (ATP) at the risk of vulnerability to Ca2+-related metabolic and oxidative pressure. This vulnerability may underlie the bidirectional nature of progression. However, recent evidence highlights that the optic projection in glaucoma is not passive but rather demonstrates adaptive processes that may push back against neurodegeneration. In the retina, even as synaptic and dendritic pruning ensues, early progression involves enhanced excitability of RGCs. Enhancement involves depolarization of the resting membrane potential and increased response to light, independent of RGC morphological type. This response is axogenic, arising from increased levels and translocation of voltage-gated sodium channels (NaV) in the unmyelinated segment. During this same early period, large-scale networks of gap-junction coupled astrocytes redistribute metabolic resources to the optic projection stressed by elevated IOP to slow loss of axon function. This redistribution may reflect more local remodeling, as astrocyte processes respond to focal metabolic duress by boosting glycogen turnover in response to axonal activity in an effort to promote survival of the healthiest axons. Both enhanced excitability and metabolic redistribution are transient, indicating that the same adaptive mechanisms that apparently serve to slow progression ultimately may be too expensive for the system to sustain over longer periods.
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Affiliation(s)
- David J Calkins
- The Vanderbilt Eye Institute, Nashville, TN, USA; Vanderbilt Vision Research Center, Vanderbilt University Medical Center, 1161 21st Ave S, AA7100 Medical Center North Nashville, Tennessee, 37232, USA.
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Kang JJ, Fung ML, Zhang K, Lam CS, Wu SX, Huang XF, Yang SJ, Wong-Riley MTT, Liu YY. Chronic intermittent hypoxia alters the dendritic mitochondrial structure and activity in the pre-Bötzinger complex of rats. FASEB J 2020; 34:14588-14601. [PMID: 32910512 DOI: 10.1096/fj.201902141r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 07/21/2020] [Accepted: 08/17/2020] [Indexed: 11/11/2022]
Abstract
Mitochondrial bioenergetics is dynamically coupled with neuronal activities, which are altered by hypoxia-induced respiratory neuroplasticity. Here we report structural features of postsynaptic mitochondria in the pre-Bötzinger complex (pre-BötC) of rats treated with chronic intermittent hypoxia (CIH) simulating a severe condition of obstructive sleep apnea. The subcellular changes in dendritic mitochondria and histochemistry of cytochrome c oxidase (CO) activity were examined in pre-BötC neurons localized by immunoreactivity of neurokinin 1 receptors. Assays of mitochondrial electron transport chain (ETC) complex I, IV, V activities, and membrane potential were performed in the ventrolateral medulla containing the pre-BötC region. We found significant decreases in the mean length and area of dendritic mitochondria in the pre-BötC of CIH rats, when compared to the normoxic control and hypoxic group with daily acute intermittent hypoxia (dAIH) that evokes robust synaptic plasticity. Notably, these morphological alterations were mainly observed in the mitochondria in close proximity to the synapses. In addition, the proportion of mitochondria presented with enlarged compartments and filamentous cytoskeletal elements in the CIH group was less than the control and dAIH groups. Intriguingly, these distinct characteristics of structural adaptability were observed in the mitochondria within spatially restricted dendritic spines. Furthermore, the proportion of moderately to darkly CO-reactive mitochondria was reduced in the CIH group, indicating reduced mitochondrial activity. Consistently, mitochondrial ETC enzyme activities and membrane potential were lowered in the CIH group. These findings suggest that hypoxia-induced respiratory plasticity was characterized by spatially confined mitochondrial alterations within postsynaptic spines in the pre-BötC neurons. In contrast to the robust plasticity evoked by dAIH preconditioning, a severe CIH challenge may weaken the local mitochondrial bioenergetics that the fuel postsynaptic activities of the respiratory motor drive.
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Affiliation(s)
- Jun-Jun Kang
- Department of Neurobiology, The Fourth Military Medical University, Xi'an, China
| | - Man-Lung Fung
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Kun Zhang
- Department of Neurobiology, The Fourth Military Medical University, Xi'an, China
| | - Chun-Sing Lam
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Sheng-Xi Wu
- Department of Neurobiology, The Fourth Military Medical University, Xi'an, China
| | - Xiao-Feng Huang
- Department of Pathology and Pathophysiology, The Fourth Military Medical University, Xi'an, China
| | - Shou-Jing Yang
- Department of Pathology and Pathophysiology, The Fourth Military Medical University, Xi'an, China
| | - Margaret T T Wong-Riley
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Ying-Ying Liu
- Department of Neurobiology, The Fourth Military Medical University, Xi'an, China
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10
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Theocharopoulou G. The ubiquitous role of mitochondria in Parkinson and other neurodegenerative diseases. AIMS Neurosci 2020; 7:43-65. [PMID: 32455165 PMCID: PMC7242057 DOI: 10.3934/neuroscience.2020004] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 02/05/2020] [Indexed: 12/14/2022] Open
Abstract
Orderly mitochondrial life cycle, plays a key role in the pathology of neurodegenerative diseases. Mitochondria are ubiquitous in neurons as they respond to an ever-changing demand for energy supply. Mitochondria constantly change in shape and location, feature of their dynamic nature, which facilitates a quality control mechanism. Biological studies in mitochondria dynamics are unveiling the mechanisms of fission and fusion, which essentially arrange morphology and motility of these organelles. Control of mitochondrial network homeostasis is a critical factor for the proper function of neurons. Disease-related genes have been reported to be implicated in mitochondrial dysfunction. Increasing evidence implicate mitochondrial perturbation in neuronal diseases, such as AD, PD, HD, and ALS. The intricacy involved in neurodegenerative diseases and the dynamic nature of mitochondria point to the idea that, despite progress toward detecting the biology underlying mitochondrial disorders, its link to these diseases is difficult to be identified in the laboratory. Considering the need to model signaling pathways, both in spatial and temporal level, there is a challenge to use a multiscale modeling framework, which is essential for understanding the dynamics of a complex biological system. The use of computational models in order to represent both a qualitative and a quantitative structure of mitochondrial homeostasis, allows to perform simulation experiments so as to monitor the conformational changes, as well as the intersection of form and function.
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11
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Cucinotta FA, Cacao E. Risks of cognitive detriments after low dose heavy ion and proton exposures. Int J Radiat Biol 2019; 95:985-998. [PMID: 31120359 PMCID: PMC6606350 DOI: 10.1080/09553002.2019.1623427] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/16/2019] [Accepted: 04/25/2019] [Indexed: 12/15/2022]
Abstract
Purpose: Heavy ion and proton brain irradiations occur during space travel and in Hadron therapy for cancer. Heavy ions produce distinct patterns of energy deposition in neuron cells and brain tissues compared to X-rays leading to large uncertainties in risk estimates. We make a critical review of findings from research studies over the last 25 years for understanding risks at low dose. Conclusions: A large number of mouse and rat cognitive testing measures have been reported for a variety of particle species and energies for acute doses. However, tissue reactions occur above dose thresholds and very few studies were performed at the heavy ion doses to be encountered on space missions (<0.04 Gy/y) or considered dose-rate effects, such that threshold doses are not known in rodent models. Investigations of possible mechanisms for cognitive changes have been limited by experimental design with largely group specific and not subject specific findings reported. Persistent oxidative stress and activated microglia cells are common mechanisms studied, while impairment of neurogenesis, detriments in neuron morphology, and changes to gene and protein expression were each found to be important in specific studies. Future research should focus on estimating threshold doses carried out with experimental designs aimed at understating causative mechanisms, which will be essential for extrapolating rodent findings to humans and chronic radiation scenarios, while establishing if mitigation are needed.
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12
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Xie LL, Shi F, Tan Z, Li Y, Bode AM, Cao Y. Mitochondrial network structure homeostasis and cell death. Cancer Sci 2018; 109:3686-3694. [PMID: 30312515 PMCID: PMC6272111 DOI: 10.1111/cas.13830] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 07/16/2018] [Accepted: 09/27/2018] [Indexed: 12/12/2022] Open
Abstract
Mitochondria are the major cellular energy‐producing organelles and intracellular source of reactive oxygen species. These organelles are responsible for driving cell life and death through mitochondrial network structure homeostasis, which is determined by a balance of fission and fusion. Recent advances revealed that a number of components of the fission and fusion machinery, including dynamin‐related protein 1 (Drp1), mitofusin1/2 (Mfn1/2) and Optic atrophy 1 (OPA1), that have been implicated in mitochondrial shape changes are indispensible for autophagy, apoptosis and necroptosis. Drp1 is the main regulator of mitochondrial fission and has become a key point of contention. The controversy focuses on whether Drp1 is directly involved in the regulation of cell death and, if involved, whether is it a stimulator or a negative regulator of cell death. Here, we examine the relevance of the homeostasis of the mitochondrial network structure in 3 different types of cell death, including autophagy, apoptosis and necroptosis. Furthermore, a variety of cancers often exhibit a fragmented mitochondrial phenotype. Thus, the fragmented ratio can reflect tumor progression that predicts prognosis and therapeutic response. In addition, we investigate whether the targeting of the mitochondrial fission protein Drp1 could be a novel therapeutic approach.
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Affiliation(s)
- Long-Long Xie
- Key Laboratory of Cancer Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China.,Research Center for Technologies to Nucleic Acid-Based Diagnostics and Therapeutics, Changsha Human Province, Changsha, China
| | - Feng Shi
- Key Laboratory of Cancer Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China.,Research Center for Technologies to Nucleic Acid-Based Diagnostics and Therapeutics, Changsha Human Province, Changsha, China
| | - Zheqiong Tan
- Key Laboratory of Cancer Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China.,Research Center for Technologies to Nucleic Acid-Based Diagnostics and Therapeutics, Changsha Human Province, Changsha, China
| | - Yueshuo Li
- Key Laboratory of Cancer Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China.,Research Center for Technologies to Nucleic Acid-Based Diagnostics and Therapeutics, Changsha Human Province, Changsha, China
| | - Ann M Bode
- The Hormel Institute, University of Minnesota, Austin, Minnesota
| | - Ya Cao
- Key Laboratory of Cancer Carcinogenesis and Invasion, Chinese Ministry of Education, Xiangya Hospital, Central South University, Changsha, China.,Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Carcinogenesis, Chinese Ministry of Health, Changsha, China.,Research Center for Technologies to Nucleic Acid-Based Diagnostics and Therapeutics, Changsha Human Province, Changsha, China
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13
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Rumora AE, LoGrasso G, Haidar JA, Dolkowski JJ, Lentz SI, Feldman EL. Chain length of saturated fatty acids regulates mitochondrial trafficking and function in sensory neurons. J Lipid Res 2018; 60:58-70. [PMID: 30442656 DOI: 10.1194/jlr.m086843] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 10/17/2018] [Indexed: 12/21/2022] Open
Abstract
Dyslipidemia associated with T2D leads to diabetic neuropathy, a complication characterized by sensory neuronal dysfunction and peripheral nerve damage. Sensory dorsal root ganglion (DRG) neurons are dependent on axonal mitochondrial energy production facilitated by mitochondrial transport mechanisms that distribute mitochondria throughout the axon. Because long-chain saturated FAs (SFAs) damage DRG neurons and medium-chain SFAs are reported to improve neuronal function, we evaluated the impact of SFA chain length on mitochondrial trafficking, mitochondrial function, and apoptosis. DRG neurons were exposed to SFAs with C12:0-C18:0 chain lengths and evaluated for changes in mitochondrial trafficking, mitochondrial polarization, and apoptosis. DRG neurons treated with C16:0 and C18:0 SFAs showed a significant decrease in the percentage of motile mitochondria and velocity of mitochondrial trafficking, whereas C12:0 and C14:0 SFAs had no impact on motility. Treatment with C16:0 and C18:0 SFAs exhibited mitochondrial depolarization correlating with impaired mitochondrial motility; the C12:0- and C14:0-treated neurons retained mitochondrial polarization. The reduction in mitochondrial trafficking and function in C16:0- and C18:0-treated DRG neurons correlated with apoptosis that was blocked in C12:0 and C14:0 SFA treatments. These results suggest that SFA chain length plays an important role in regulating axonal mitochondrial trafficking and function in DRG neurons.
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Affiliation(s)
- Amy E Rumora
- Departments of Neurology University of Michigan, Ann Arbor, MI 48109
| | - Giovanni LoGrasso
- Departments of Neurology University of Michigan, Ann Arbor, MI 48109
| | - Julia A Haidar
- Departments of Neurology University of Michigan, Ann Arbor, MI 48109
| | - Justin J Dolkowski
- Departments of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Stephen I Lentz
- Departments of Internal Medicine, University of Michigan, Ann Arbor, MI 48109
| | - Eva L Feldman
- Departments of Neurology University of Michigan, Ann Arbor, MI 48109
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14
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MacDougall G, Anderton RS, Mastaglia FL, Knuckey NW, Meloni BP. Mitochondria and neuroprotection in stroke: Cationic arginine-rich peptides (CARPs) as a novel class of mitochondria-targeted neuroprotective therapeutics. Neurobiol Dis 2018; 121:17-33. [PMID: 30218759 DOI: 10.1016/j.nbd.2018.09.010] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 08/26/2018] [Accepted: 09/11/2018] [Indexed: 01/11/2023] Open
Abstract
Stroke is the second leading cause of death globally and represents a major cause of devastating long-term disability. Despite sustained efforts to develop clinically effective neuroprotective therapies, presently there is no clinically available neuroprotective agent for stroke. As a central mediator of neurodamaging events in stroke, mitochondria are recognised as a critical neuroprotective target, and as such, provide a focus for developing mitochondrial-targeted therapeutics. In recent years, cationic arginine-rich peptides (CARPs) have been identified as a novel class of neuroprotective agent with several demonstrated mechanisms of action, including their ability to target mitochondria and exert positive effects on the organelle. This review provides an overview on neuronal mitochondrial dysfunction in ischaemic stroke pathophysiology and highlights the potential beneficial effects of CARPs on mitochondria in the ischaemic brain following stroke.
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Affiliation(s)
- Gabriella MacDougall
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, Australia; Perron Institute for Neurological and Translational Science, Nedlands, Australia; School of Heath Sciences, and Institute for Health Research, The University Notre Dame Australia, Fremantle, Australia.
| | - Ryan S Anderton
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, Australia; Perron Institute for Neurological and Translational Science, Nedlands, Australia; School of Heath Sciences, and Institute for Health Research, The University Notre Dame Australia, Fremantle, Australia
| | - Frank L Mastaglia
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, Australia; Perron Institute for Neurological and Translational Science, Nedlands, Australia
| | - Neville W Knuckey
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, Australia; Perron Institute for Neurological and Translational Science, Nedlands, Australia; Department of Neurosurgery, Sir Charles Gairdner Hospital, QEII Medical Centre, Nedlands, Western Australia, Australia
| | - Bruno P Meloni
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, Australia; Perron Institute for Neurological and Translational Science, Nedlands, Australia; Department of Neurosurgery, Sir Charles Gairdner Hospital, QEII Medical Centre, Nedlands, Western Australia, Australia
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15
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Kim JE, Kang TC. Differential Roles of Mitochondrial Translocation of Active Caspase-3 and HMGB1 in Neuronal Death Induced by Status Epilepticus. Front Cell Neurosci 2018; 12:301. [PMID: 30233331 PMCID: PMC6133957 DOI: 10.3389/fncel.2018.00301] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/17/2018] [Indexed: 11/13/2022] Open
Abstract
Under pathophysiological conditions, aberrant mitochondrial dynamics lead to the different types of neuronal death: excessive mitochondrial fission provokes apoptosis and abnormal mitochondrial elongation induces necrosis. However, the underlying mechanisms how the different mitochondrial dynamics result in the distinct neuronal death patterns have been elusive. In the present study, status epilepticus (SE) evoked excessive mitochondrial fission in parvalbumin (PV) cells (one of GABAergic interneurons) and abnormal mitochondrial elongation in CA1 neurons in the rat hippocampus. These impaired mitochondrial dynamics were accompanied by mitochondrial translocations of active caspase-3 and high mobility group box 1 (HMGB1) in PV cells and CA1 neurons, respectively. WY14643 (an activator of mitochondrial fission) aggravated SE-induced PV cell loss by enhancing active caspase-3 induction and its mitochondrial translocation, which were attenuated by Mdivi-1 (an inhibitor of mitochondrial fission). Mitochondrial HMGB1 import was not observed in PV cell. In contrast to PV cells, Mdivi-1 deteriorated SE-induced CA1 neuronal death concomitant with mitochondrial HMGB1 translocation, which was abrogated by WY14643. These findings suggest that SE-induced aberrant mitochondrial dynamics may be involved in translocation of active caspase-3 and HMGB1 into mitochondria, which regulate neuronal apoptosis and necrosis, respectively.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, South Korea
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16
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Hill RL, Kulbe JR, Singh IN, Wang JA, Hall ED. Synaptic Mitochondria are More Susceptible to Traumatic Brain Injury-induced Oxidative Damage and Respiratory Dysfunction than Non-synaptic Mitochondria. Neuroscience 2018; 386:265-283. [PMID: 29960045 DOI: 10.1016/j.neuroscience.2018.06.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 06/12/2018] [Accepted: 06/18/2018] [Indexed: 12/17/2022]
Abstract
Traumatic brain injury (TBI) results in mitochondrial dysfunction and induction of lipid peroxidation (LP). Lipid peroxidation-derived neurotoxic aldehydes such as 4-HNE and acrolein bind to mitochondrial proteins, inducing additional oxidative damage and further exacerbating mitochondrial dysfunction and LP. Mitochondria are heterogeneous, consisting of both synaptic and non-synaptic populations. Synaptic mitochondria are reported to be more vulnerable to injury; however, this is the first study to characterize the temporal profile of synaptic and non-synaptic mitochondria following TBI, including investigation of respiratory dysfunction and oxidative damage to mitochondrial proteins between 3 and 120 h following injury. These results indicate that synaptic mitochondria are indeed the more vulnerable population, showing both more rapid and severe impairments than non-synaptic mitochondria. By 24 h, synaptic respiration is significantly impaired compared to synaptic sham, whereas non-synaptic respiration does not decline significantly until 48 h. Decreases in respiration are associated with increases in oxidative damage to synaptic and non-synaptic mitochondrial proteins at 48 h and 72 h, respectively. These results indicate that the therapeutic window for mitochondria-targeted pharmacological neuroprotectants to prevent respiratory dysfunction is shorter for the more vulnerable synaptic mitochondria than for the non-synaptic population.
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Affiliation(s)
- Rachel L Hill
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States
| | - Jacqueline R Kulbe
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States; Department of Neuroscience, University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States
| | - Indrapal N Singh
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States; Department of Neuroscience, University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States
| | - Juan A Wang
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States
| | - Edward D Hall
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States; Department of Neuroscience, University of Kentucky College of Medicine, 741 S. Limestone St, Lexington, KY 40536-0509, United States.
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17
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Rybnicek J, Samtleben S, Herrera-Cruz MS, Simmen T. Expression of a T39N mutant Rab32 protein arrests mitochondria movement within neurites of differentiated SH-SY5Y cells. Small GTPases 2018; 11:289-292. [PMID: 29261068 DOI: 10.1080/21541248.2017.1411312] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
We have shown that multiple sclerosis (MS) and endoplasmic reticulum (ER) stress induce Rab32, an ER/mitochondria-localized small GTPase. High levels of both dominant-active (Q85L) or dominant-inactive (T39N) Rab32 are toxic to neurons. While Rab32Q85L interacts with its effector Drp1 to promote mitochondria fission, it is unclear how Rab32T39N could result as toxic to neurons. Given the perinuclear clustering of mitochondria observed upon transfection of inactive Rab32, we hypothesized Rab32T39N could stall mitochondria within neurites. The movement of mitochondria depends on kinesin-binding Miro proteins. High cytosolic [Ca2+] is bound by an EF hand motif within Miro proteins, resulting in mitochondrial arrest. Consistent with increased cytosolic [Ca2+], expression of Rab32T39N arrests mitochondria movement within neurites.
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Affiliation(s)
- Jonas Rybnicek
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta , Edmonton, Alberta, Canada, T6R0K8
| | - Samira Samtleben
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta , Edmonton, Alberta, Canada, T6R0K8
| | - Maria Sol Herrera-Cruz
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta , Edmonton, Alberta, Canada, T6R0K8
| | - Thomas Simmen
- Faculty of Medicine and Dentistry, Department of Cell Biology, University of Alberta , Edmonton, Alberta, Canada, T6R0K8
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18
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Rumora AE, Lentz SI, Hinder LM, Jackson SW, Valesano A, Levinson GE, Feldman EL. Dyslipidemia impairs mitochondrial trafficking and function in sensory neurons. FASEB J 2018; 32:195-207. [PMID: 28904018 PMCID: PMC6191072 DOI: 10.1096/fj.201700206r] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 08/21/2017] [Indexed: 01/11/2023]
Abstract
Mitochondrial trafficking plays a central role in dorsal root ganglion (DRG) neuronal cell survival and neurotransmission by transporting mitochondria from the neuronal cell body throughout the bundles of DRG axons. In type 2 diabetes (T2DM), dyslipidemia and hyperglycemia damage DRG neurons and induce mitochondrial dysfunction; however, the impact of free fatty acids and glucose on mitochondrial trafficking in DRG neurons remains unknown. To evaluate the impact of free fatty acids compared to hyperglycemia on mitochondrial transport, primary adult mouse DRG neuron cultures were treated with physiologic concentrations of palmitate and glucose and assessed for alterations in mitochondrial trafficking, mitochondrial membrane potential, and mitochondrial bioenergetics. Palmitate treatment significantly reduced the number of motile mitochondria in DRG axons, but physiologic concentrations of glucose did not impair mitochondrial trafficking dynamics. Palmitate-treated DRG neurons also exhibited a reduction in mitochondrial velocity, and impaired mitochondrial trafficking correlated with mitochondrial depolarization in palmitate-treated DRG neurons. Finally, we found differential bioenergetic effects of palmitate and glucose on resting and energetically challenged mitochondria in DRG neurons. Together, these results suggest that palmitate induces DRG neuron mitochondrial depolarization, inhibiting axonal mitochondrial trafficking and altering mitochondrial bioenergetic capacity.-Rumora, A. E., Lentz, S. I., Hinder, L. M., Jackson, S. W., Valesano, A., Levinson, G. E., Feldman, E. L. Dyslipidemia impairs mitochondrial trafficking and function in sensory neurons.
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Affiliation(s)
- Amy E Rumora
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Stephen I Lentz
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Lucy M Hinder
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Samuel W Jackson
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Andrew Valesano
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Gideon E Levinson
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Eva L Feldman
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA;
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19
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Kim JE, Kang TC. p47Phox/CDK5/DRP1-Mediated Mitochondrial Fission Evokes PV Cell Degeneration in the Rat Dentate Gyrus Following Status Epilepticus. Front Cell Neurosci 2017; 11:267. [PMID: 28919853 PMCID: PMC5585136 DOI: 10.3389/fncel.2017.00267] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 08/21/2017] [Indexed: 01/31/2023] Open
Abstract
Parvalbumin (PV) is one of the calcium-binding proteins, which plays an important role in the responsiveness of inhibitory neurons to an adaptation to repetitive spikes. Furthermore, PV neurons are highly vulnerable to status epilepticus (SE, prolonged seizure activity), although the underlining mechanism remains to be clarified. In the present study, we found that p47Phox expression was transiently and selectively increased in PV neurons 6 h after SE. This up-regulated p47Phox expression was accompanied by excessive mitochondrial fission. In this time point, CDK5-tyrosine 15 and dynamin-related protein 1 (DRP1)-serine 616 phosphorylations were also increased in PV cells. Apocynin (a p47Phox inhibitor) effectively mitigated PV cell loss via inhibition of CDK5/DRP1 phosphorylations and mitochondrial fragmentation induced by SE. Roscovitine (a CDK5 inhibitor) and Mdivi-1 (a DRP1 inhibitor) attenuated SE-induced PV cell loss by inhibiting aberrant mitochondrial fission. These findings suggest that p47Phox/CDK5/DRP1 may be one of the important upstream signaling pathways in PV cell degeneration induced by SE via excessive mitochondrial fragmentation.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym UniversityChuncheon, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym UniversityChuncheon, South Korea
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20
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Leaw B, Nair S, Lim R, Thornton C, Mallard C, Hagberg H. Mitochondria, Bioenergetics and Excitotoxicity: New Therapeutic Targets in Perinatal Brain Injury. Front Cell Neurosci 2017; 11:199. [PMID: 28747873 PMCID: PMC5506196 DOI: 10.3389/fncel.2017.00199] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 06/26/2017] [Indexed: 12/30/2022] Open
Abstract
Injury to the fragile immature brain is implicated in the manifestation of long-term neurological disorders, including childhood disability such as cerebral palsy, learning disability and behavioral disorders. Advancements in perinatal practice and improved care mean the majority of infants suffering from perinatal brain injury will survive, with many subtle clinical symptoms going undiagnosed until later in life. Hypoxic-ischemia is the dominant cause of perinatal brain injury, and constitutes a significant socioeconomic burden to both developed and developing countries. Therapeutic hypothermia is the sole validated clinical intervention to perinatal asphyxia; however it is not always neuroprotective and its utility is limited to developed countries. There is an urgent need to better understand the molecular pathways underlying hypoxic-ischemic injury to identify new therapeutic targets in such a small but critical therapeutic window. Mitochondria are highly implicated following ischemic injury due to their roles as the powerhouse and main energy generators of the cell, as well as cell death processes. While the link between impaired mitochondrial bioenergetics and secondary energy failure following loss of high-energy phosphates is well established after hypoxia-ischemia (HI), there is emerging evidence that the roles of mitochondria in disease extend far beyond this. Indeed, mitochondrial turnover, including processes such as mitochondrial biogenesis, fusion, fission and mitophagy, affect recovery of neurons after injury and mitochondria are involved in the regulation of the innate immune response to inflammation. This review article will explore these mitochondrial pathways, and finally will summarize past and current efforts in targeting these pathways after hypoxic-ischemic injury, as a means of identifying new avenues for clinical intervention.
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Affiliation(s)
- Bryan Leaw
- The Ritchie Centre, Hudson Institute of Medical ResearchClayton, VIC, Australia
| | - Syam Nair
- Perinatal Center, Institute of Physiology and Neuroscience, Sahlgrenska Academy, University of GothenburgGothenburg, Sweden
| | - Rebecca Lim
- The Ritchie Centre, Hudson Institute of Medical ResearchClayton, VIC, Australia.,Department of Obstetrics and Gynaecology, Monash University ClaytonClayton, VIC, Australia
| | - Claire Thornton
- Centre for the Developing Brain, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' HospitalLondon, United Kingdom
| | - Carina Mallard
- Perinatal Center, Institute of Physiology and Neuroscience, Sahlgrenska Academy, University of GothenburgGothenburg, Sweden
| | - Henrik Hagberg
- Centre for the Developing Brain, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas' HospitalLondon, United Kingdom.,Perinatal Center, Department of Clinical Sciences, Sahlgrenska Academy, Gothenburg UniversityGothenburg, Sweden
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21
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Abstract
Mitochondria mediate energy metabolism, apoptosis, and aging, while mitochondrial disruption leads to age-related diseases that include age-related macular degeneration. Descriptions of mitochondrial morphology have been non-systematic and qualitative, due to lack of knowledge on the molecular mechanism of mitochondrial dynamics. The current study analyzed mitochondrial size, shape, and position quantitatively in retinal pigment epithelial cells (RPE) using a systematic computational model to suggest mitochondrial trafficking under oxidative environment. Our previous proteomic study suggested that prohibitin is a mitochondrial decay biomarker in the RPE. The current study examined the prohibitin interactome map using immunoprecipitation data to determine the indirect signaling on cytoskeletal changes and transcriptional regulation by prohibitin. Immunocytochemistry and immunoprecipitation demonstrated that there is a positive correlation between mitochondrial changes and altered filaments as well as prohibitin interactions with kinesin and unknown proteins in the RPE. Specific cytoskeletal and nuclear protein-binding mechanisms may exist to regulate prohibitin-mediated reactions as key elements, including vimentin and p53, to control apoptosis in mitochondria and the nucleus. Prohibitin may regulate mitochondrial trafficking through unknown proteins that include 110 kDa protein with myosin head domain and 88 kDa protein with cadherin repeat domain. Altered cytoskeleton may represent a mitochondrial decay signature in the RPE. The current study suggests that mitochondrial dynamics and cytoskeletal changes are critical for controlling mitochondrial distribution and function. Further, imbalance of retrograde versus anterograde mitochondrial trafficking may initiate the pathogenic reaction in adult-onset neurodegenerative diseases.
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22
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Hyun HW, Min SJ, Kim JE. CDK5 inhibitors prevent astroglial apoptosis and reactive astrogliosis by regulating PKA and DRP1 phosphorylations in the rat hippocampus. Neurosci Res 2017; 119:24-37. [PMID: 28153522 DOI: 10.1016/j.neures.2017.01.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 01/04/2017] [Accepted: 01/25/2017] [Indexed: 11/28/2022]
Abstract
Status epilepticus (SE) results in the unique pattern of dynamin-related protein 1 (DRP1)-mediated mitochondrial dynamics, which is associated with astroglial apoptosis and reactive astrogliosis in the regional-specific pattern representing the differential astroglial properties. However, less defined are the epiphenomena/upstream effecters for DRP1 phosphorylation in this process. Since cyclin-dependent kinase 5 (CDK5) is involved in reactive astrogliosis, CDK5 is one of the possible upstream regulators for DRP1 phosphorylation. In the present study, both olomoucine and roscovitine (CDK5 inhibitors) effectively ameliorated SE-induced astroglial apoptosis in the dentate gyrus without changed seizure susceptibility. In addition, they inhibited reactive astrogliosis in the CA1 region independent of neuronal death induced by SE. These effects of CDK5 inhibitors were relevant to abrogation of altered DRP1 phosphorylation ratio and mitochondrial length induced by SE. CDK5 inhibitors also negatively regulated protein kinase A (PKA) activity in astrocytes. Therefore, our findings suggest that CDK5 inhibitors may mitigate astroglial apoptosis and reactive astrogliosis accompanied by modulations of DRP1-mediated mitochondrial dynamics.
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Affiliation(s)
- Hye-Won Hyun
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do 24252, South Korea.
| | - Su-Ji Min
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do 24252, South Korea.
| | - Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, Kangwon-Do 24252, South Korea.
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23
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Dadhania VP, Trivedi PP, Vikram A, Tripathi DN. Nutraceuticals against Neurodegeneration: A Mechanistic Insight. Curr Neuropharmacol 2017; 14:627-40. [PMID: 26725888 PMCID: PMC4981739 DOI: 10.2174/1570159x14666160104142223] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 08/17/2015] [Accepted: 01/01/2016] [Indexed: 12/20/2022] Open
Abstract
The mechanisms underlying neurodegenerative disorders are complex and multifactorial; however, accumulating evidences suggest few common shared pathways. These common pathways include mitochondrial dysfunction, intracellular Ca2+ overload, oxidative stress and inflammation. Often multiple pathways co-exist, and therefore limit the benefits of therapeutic interventions. Nutraceuticals have recently gained importance owing to their multifaceted effects. These food-based approaches are believed to target multiple pathways in a slow but more physiological manner without causing severe adverse effects. Available information strongly supports the notion that apart from preventing the onset of neuronal damage, nutraceuticals can potentially attenuate the continued progression of neuronal destruction. In this article, we i) review the common pathways involved in the pathogenesis of the toxicants-induced neurotoxicity and neurodegenerative disorders with special emphasis on Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Multiple sclerosis (MS) and Amyotrophic lateral sclerosis (ALS), and ii) summarize current research advancements on the effects of nutraceuticals against these detrimental pathways.
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Affiliation(s)
| | | | - Ajit Vikram
- Department of Internal Medicine, The University of Iowa, Iowa City, IA-52240, USA.
| | - Durga Nand Tripathi
- DNT at Center for Translational Cancer Research, Institute of Biosciences & Technology, Texas A&M University Health Science Center, Houston, TX-77030, USA.
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Ramsay RR, Majekova M, Medina M, Valoti M. Key Targets for Multi-Target Ligands Designed to Combat Neurodegeneration. Front Neurosci 2016; 10:375. [PMID: 27597816 PMCID: PMC4992697 DOI: 10.3389/fnins.2016.00375] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 08/02/2016] [Indexed: 12/13/2022] Open
Abstract
HIGHLIGHTS Compounds that interact with multiple targets but minimally with the cytochrome P450 system (CYP) address the many factors leading to neurodegeneration.Acetyl- and Butyryl-cholineEsterases (AChE, BChE) and Monoamine Oxidases A/B (MAO A, MAO B) are targets for Multi-Target Designed Ligands (MTDL).ASS234 is an irreversible inhibitor of MAO A >MAO B and has micromolar potency against the cholinesterases.ASS234 is a poor CYP substrate in human liver, yielding the depropargylated metabolite.SMe1EC2, a stobadine derivative, showed high radical scavenging property, in vitro and in vivo giving protection in head trauma and diabetic damage of endothelium.Control of mitochondrial function and morphology by manipulating fission and fusion is emerging as a target area for therapeutic strategies to decrease the pathological outcome of neurodegenerative diseases. Growing evidence supports the view that neurodegenerative diseases have multiple and common mechanisms in their aetiologies. These multifactorial aspects have changed the broadly common assumption that selective drugs are superior to "dirty drugs" for use in therapy. This drives the research in studies of novel compounds that might have multiple action mechanisms. In neurodegeneration, loss of neuronal signaling is a major cause of the symptoms, so preservation of neurotransmitters by inhibiting the breakdown enzymes is a first approach. Acetylcholinesterase (AChE) inhibitors are the drugs preferentially used in AD and that one of these, rivastigmine, is licensed also for PD. Several studies have shown that monoamine oxidase (MAO) B, located mainly in glial cells, increases with age and is elevated in Alzheimer (AD) and Parkinson's Disease's (PD). Deprenyl, a MAO B inhibitor, significantly delays the initiation of levodopa treatment in PD patients. These indications underline that AChE and MAO are considered a necessary part of multi-target designed ligands (MTDL). However, both of these targets are simply symptomatic treatment so if new drugs are to prevent degeneration rather than compensate for loss of neurotransmitters, then oxidative stress and mitochondrial events must also be targeted. MAO inhibitors can protect neurons from apoptosis by mechanisms unrelated to enzyme inhibition. Understanding the involvement of MAO and other proteins in the induction and regulation of the apoptosis in mitochondria will aid progress toward strategies to prevent the loss of neurons. In general, the oxidative stress observed both in PD and AD indicate that antioxidant properties are a desirable part of MTDL molecules. After two or more properties are incorporated into one molecule, the passage from a lead compound to a therapeutic tool is strictly linked to its pharmacokinetic and toxicity. In this context the interaction of any new molecules with cytochrome P450 and other xenobiotic metabolic processes is a crucial point. The present review covers the biochemistry of enzymes targeted in the design of drugs against neurodegeneration and the cytochrome P450-dependent metabolism of MTDLs.
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Affiliation(s)
- Rona R. Ramsay
- Biomedical Sciences Research Complex, University of St. AndrewsSt. Andrews, UK
| | - Magdalena Majekova
- Department of Biochemical Pharmacology, Institute of Experimental Pharmacology and Toxicology, Slovak Academy of SciencesBratislava, Slovakia
| | - Milagros Medina
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias and BIFI, Universidad de ZaragozaZaragoza, Spain
| | - Massimo Valoti
- Dipartimento di Scienze della Vita, Università degli Studi di SienaSiena, Italy
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Bergman O, Ben-Shachar D. Mitochondrial Oxidative Phosphorylation System (OXPHOS) Deficits in Schizophrenia: Possible Interactions with Cellular Processes. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2016; 61:457-69. [PMID: 27412728 PMCID: PMC4959648 DOI: 10.1177/0706743716648290] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mitochondria are key players in the generation and regulation of cellular bioenergetics, producing the majority of adenosine triphosphate molecules by the oxidative phosphorylation system (OXPHOS). Linked to numerous signaling pathways and cellular functions, mitochondria, and OXPHOS in particular, are involved in neuronal development, connectivity, plasticity, and differentiation. Impairments in a variety of mitochondrial functions have been described in different general and psychiatric disorders, including schizophrenia (SCZ), a severe, chronic, debilitating illness that heavily affects the lives of patients and their families. This article reviews findings emphasizing the role of OXPHOS in the pathophysiology of SCZ. Evidence accumulated during the past few decades from imaging, transcriptomic, proteomic, and metabolomic studies points at OXPHOS deficit involvement in SCZ. Abnormalities have been reported in high-energy phosphates generated by the OXPHOS, in the activity of its complexes and gene expression, primarily of complex I (CoI). In addition, cellular signaling such as cAMP/protein kinase A (PKA) and Ca(+2), neuronal development, connectivity, and plasticity have been linked to OXPHOS function and are reported to be impaired in SCZ. Finally, CoI has been shown as a site of interaction for both dopamine (DA) and antipsychotic drugs, further substantiating its role in the pathology of SCZ. Understanding the role of mitochondria and the OXPHOS in particular may encourage new insights into the pathophysiology and etiology of this debilitating disorder.
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Affiliation(s)
- Oded Bergman
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Medical Center, Technion-IIT, Haifa, Israel B. Rappaport Faculty of Medicine, Technion-IIT, Haifa, Israel
| | - Dorit Ben-Shachar
- Laboratory of Psychobiology, Department of Psychiatry, Rambam Medical Center, Technion-IIT, Haifa, Israel B. Rappaport Faculty of Medicine, Technion-IIT, Haifa, Israel
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26
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Ko AR, Hyun HW, Min SJ, Kim JE. The Differential DRP1 Phosphorylation and Mitochondrial Dynamics in the Regional Specific Astroglial Death Induced by Status Epilepticus. Front Cell Neurosci 2016; 10:124. [PMID: 27242436 PMCID: PMC4870264 DOI: 10.3389/fncel.2016.00124] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/29/2016] [Indexed: 11/13/2022] Open
Abstract
The response and susceptibility to astroglial degenerations are relevant to the distinctive properties of astrocytes in a hemodynamic-independent manner following status epilepticus (SE). Since impaired mitochondrial fission plays an important role in mitosis, apoptosis and programmed necrosis, we investigated whether the unique pattern of mitochondrial dynamics is involved in the characteristics of astroglial death induced by SE. In the present study, SE induced astroglial apoptosis in the molecular layer of the dentate gyrus, accompanied by decreased mitochondrial length. In contrast, clasmatodendritic (autophagic) astrocytes in the CA1 region showed mitochondrial elongation induced by SE. Mdivi-1 (an inhibitor of mitochondrial fission) effectively attenuated astroglial apoptosis, but WY14643 (an enhancer of mitochondrial fission) aggravated it. In addition, Mdivi-1 accelerated clasmatodendritic changes in astrocytes. These regional specific mitochondrial dynamics in astrocytes were closely correlated with dynamin-related protein 1 (DRP1; a mitochondrial fission protein) phosphorylation, not optic atrophy 1 (OPA1; a mitochondrial fusion protein) expression. To the best of our knowledge, the present data demonstrate for the first time the novel role of DRP1-mediated mitochondrial fission in astroglial loss. Thus, the present findings suggest that the differential astroglial mitochondrial dynamics may participate in the distinct characteristics of astroglial death induced by SE.
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Affiliation(s)
- Ah-Reum Ko
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University Chuncheon, South Korea
| | - Hye-Won Hyun
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University Chuncheon, South Korea
| | - Su-Ji Min
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University Chuncheon, South Korea
| | - Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University Chuncheon, South Korea
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Niescier RF, Kwak SK, Joo SH, Chang KT, Min KT. Dynamics of Mitochondrial Transport in Axons. Front Cell Neurosci 2016; 10:123. [PMID: 27242435 PMCID: PMC4865487 DOI: 10.3389/fncel.2016.00123] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 04/29/2016] [Indexed: 11/19/2022] Open
Abstract
The polarized structure and long neurites of neurons pose a unique challenge for proper mitochondrial distribution. It is widely accepted that mitochondria move from the cell body to axon ends and vice versa; however, we have found that mitochondria originating from the axon ends moving in the retrograde direction never reach to the cell body, and only a limited number of mitochondria moving in the anterograde direction from the cell body arrive at the axon ends of mouse hippocampal neurons. Furthermore, we have derived a mathematical formula using the Fokker-Planck equation to characterize features of mitochondrial transport, and the equation could determine altered mitochondrial transport in axons overexpressing parkin. Our analysis will provide new insights into the dynamics of mitochondrial transport in axons of normal and unhealthy neurons.
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Affiliation(s)
- Robert F Niescier
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology Ulsan, South Korea
| | - Sang Kyu Kwak
- Department of Chemical Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and TechnologyUlsan, South Korea; Center for Multidimensional Carbon Materials, Institute for Basic ScienceUlsan, South Korea
| | - Se Hun Joo
- Department of Chemical Engineering, School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology Ulsan, South Korea
| | - Karen T Chang
- Zilkha Neurogenetic Institute and Department of Cell and Neurobiology, University of Southern California Los Angeles, CA, USA
| | - Kyung-Tai Min
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology Ulsan, South Korea
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28
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Central visual pathways in glaucoma: evidence for distal mechanisms of neuronal self-repair. J Neuroophthalmol 2016; 35 Suppl 1:S29-37. [PMID: 26274834 DOI: 10.1097/wno.0000000000000291] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
As in other age-related neurodegenerative diseases, progression of neurodegeneration in glaucoma involves early axonopathy. In glaucoma, this is marked by degradation of active transport along retinal ganglion cell (RGC) axons projecting from the retina to the brain. In experimental systems, transport degradation occurs first in the most distal site in the RGC projection, the superior colliculus (SC) of the midbrain. Even as degradation progresses from one retinotopic sector to the next, important structures in the affected sectors persist, including synapses from RGC axon terminals onto SC neurons. This structural persistence is accompanied by focally increased brain-derived neurotrophic factor in hypertrophic SC astrocyte glia and defines a therapeutic window of opportunity. Thus, central brain structures in glaucoma may respond to disease-relevant stress by induction of mechanisms useful for maintaining retinal signals.
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Lores-Arnaiz S, Lombardi P, Karadayian AG, Orgambide F, Cicerchia D, Bustamante J. Brain cortex mitochondrial bioenergetics in synaptosomes and non-synaptic mitochondria during aging. Neurochem Res 2016; 41:353-63. [DOI: 10.1007/s11064-015-1817-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 12/23/2015] [Accepted: 12/25/2015] [Indexed: 10/22/2022]
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Kif5 regulates mitochondrial movement, morphology, function and neuronal survival. Mol Cell Neurosci 2016; 72:22-33. [PMID: 26767417 DOI: 10.1016/j.mcn.2015.12.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 12/15/2015] [Accepted: 12/31/2015] [Indexed: 11/21/2022] Open
Abstract
Due to the unique architecture of neurons, trafficking of mitochondria throughout processes to regions of high energetic demand is critical to sustain neuronal health. It has been suggested that compromised mitochondrial trafficking may play a role in neurodegenerative diseases. We evaluated the consequences of disrupted kif5c-mediated mitochondrial trafficking on mitochondrial form and function in primary rat cortical neurons. Morphological changes in mitochondria appeared to be due to remodelling, a phenomenon distinct from mitochondrial fission, which resulted in punctate-shaped mitochondria. We also demonstrated that neurons displaying punctate mitochondria exhibited relatively decreased ROS and increased cellular ATP levels using ROS-sensitive GFP and ATP FRET probes, respectively. Somewhat unexpectedly, neurons overexpressing the dominant negative form of kif5c exhibited enhanced survival following excitotoxicity, suggesting that the impairment of mitochondrial trafficking conferred some form of neuroprotection. However, when neurons were exposed to H2O2, disruption of kif5c exacerbated cell death indicating that the effect on cell viability was dependent on the mode of toxicity. Our results suggest a novel role of kif5c. In addition to mediating mitochondrial transport, kif5c plays a role in the mechanism of regulating mitochondrial morphology. Our results also suggest that kif5c mediated mitochondrial dynamics may play an important role in regulating mitochondrial function and in turn cellular health. Moreover, our studies demonstrate an interesting interplay between the regulation of mitochondrial motility and morphology.
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31
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Neve A, Trüb J, Saxena S, Schümperli D. Central and peripheral defects in motor units of the diaphragm of spinal muscular atrophy mice. Mol Cell Neurosci 2016; 70:30-41. [PMID: 26621405 DOI: 10.1016/j.mcn.2015.11.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 10/30/2015] [Accepted: 11/23/2015] [Indexed: 01/08/2023] Open
Abstract
Spinal muscular atrophy (SMA) is characterized by motoneuron loss and muscle weakness. However, the structural and functional deficits that lead to the impairment of the neuromuscular system remain poorly defined. By electron microscopy, we previously found that neuromuscular junctions (NMJs) and muscle fibres of the diaphragm are among the earliest affected structures in the severe mouse SMA model. Because of certain anatomical features, i.e. its thinness and its innervation from the cervical segments of the spinal cord, the diaphragm is particularly suitable to characterize both central and peripheral events. Here we show by immunohistochemistry that, at postnatal day 3, the cervical motoneurons of SMA mice receive less stimulatory synaptic inputs. Moreover, their mitochondria become less elongated which might represent an early stage of degeneration. The NMJs of the diaphragm of SMA mice show a loss of synaptic vesicles and active zones. Moreover, the partly innervated endplates lack S100 positive perisynaptic Schwann cells (PSCs). We also demonstrate the feasibility of comparing the proteomic composition between diaphragm regions enriched and poor in NMJs. By this approach we have identified two proteins that are significantly upregulated only in the NMJ-specific regions of SMA mice. These are apoptosis inducing factor 1 (AIFM1), a mitochondrial flavoprotein that initiates apoptosis in a caspase-independent pathway, and four and a half Lim domain protein 1 (FHL1), a regulator of skeletal muscle mass that has been implicated in several myopathies.
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Affiliation(s)
- Anuja Neve
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Judith Trüb
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland
| | - Smita Saxena
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland
| | - Daniel Schümperli
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland.
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Ketamine causes mitochondrial dysfunction in human induced pluripotent stem cell-derived neurons. PLoS One 2015; 10:e0128445. [PMID: 26020236 PMCID: PMC4447382 DOI: 10.1371/journal.pone.0128445] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 04/27/2015] [Indexed: 02/06/2023] Open
Abstract
Purpose Ketamine toxicity has been demonstrated in nonhuman mammalian neurons. To study the toxic effect of ketamine on human neurons, an experimental model of cultured neurons from human induced pluripotent stem cells (iPSCs) was examined, and the mechanism of its toxicity was investigated. Methods Human iPSC-derived dopaminergic neurons were treated with 0, 20, 100 or 500 μM ketamine for 6 and 24 h. Ketamine toxicity was evaluated by quantification of caspase 3/7 activity, reactive oxygen species (ROS) production, mitochondrial membrane potential, ATP concentration, neurotransmitter reuptake activity and NADH/NAD+ ratio. Mitochondrial morphological change was analyzed by transmission electron microscopy and confocal microscopy. Results Twenty-four-hour exposure of iPSC-derived neurons to 500 μM ketamine resulted in a 40% increase in caspase 3/7 activity (P < 0.01), 14% increase in ROS production (P < 0.01), and 81% reduction in mitochondrial membrane potential (P < 0.01), compared with untreated cells. Lower concentration of ketamine (100 μM) decreased the ATP level (22%, P < 0.01) and increased the NADH/NAD+ ratio (46%, P < 0.05) without caspase activation. Transmission electron microscopy showed enhanced mitochondrial fission and autophagocytosis at the 100 μM ketamine concentration, which suggests that mitochondrial dysfunction preceded ROS generation and caspase activation. Conclusions We established an in vitro model for assessing the neurotoxicity of ketamine in iPSC-derived neurons. The present data indicate that the initial mitochondrial dysfunction and autophagy may be related to its inhibitory effect on the mitochondrial electron transport system, which underlies ketamine-induced neural toxicity. Higher ketamine concentration can induce ROS generation and apoptosis in human neurons.
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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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34
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Revisiting the neuropathogenesis of Zellweger syndrome. Neurochem Int 2014; 69:1-8. [DOI: 10.1016/j.neuint.2014.02.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 02/11/2014] [Accepted: 02/24/2014] [Indexed: 01/27/2023]
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Barbosa DJ, Serrat R, Mirra S, Quevedo M, de Barreda EG, Àvila J, Ferreira LM, Branco PS, Fernandes E, Lourdes Bastos MD, Capela JP, Soriano E, Carvalho F. The mixture of "ecstasy" and its metabolites impairs mitochondrial fusion/fission equilibrium and trafficking in hippocampal neurons, at in vivo relevant concentrations. Toxicol Sci 2014; 139:407-20. [PMID: 24595818 DOI: 10.1093/toxsci/kfu042] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
3,4-Methylenedioxymethamphetamine (MDMA; "ecstasy") is a potentially neurotoxic recreational drug of abuse. Though the mechanisms involved are still not completely understood, formation of reactive metabolites and mitochondrial dysfunction contribute to MDMA-related neurotoxicity. Neuronal mitochondrial trafficking, and their targeting to synapses, is essential for proper neuronal function and survival, rendering neurons particularly vulnerable to mitochondrial dysfunction. Indeed, MDMA-associated disruption of Ca(2+) homeostasis and ATP depletion have been described in neurons, thus suggesting possible MDMA interference on mitochondrial dynamics. In this study, we performed real-time functional experiments of mitochondrial trafficking to explore the role of in situ mitochondrial dysfunction in MDMA's neurotoxic actions. We show that the mixture of MDMA and six of its major in vivo metabolites, each compound at 10μM, impaired mitochondrial trafficking and increased the fragmentation of axonal mitochondria in cultured hippocampal neurons. Furthermore, the overexpression of mitofusin 2 (Mfn2) or dynamin-related protein 1 (Drp1) K38A constructs almost completely rescued the trafficking deficits caused by this mixture. Finally, in hippocampal neurons overexpressing a Mfn2 mutant, Mfn2 R94Q, with impaired fusion and transport properties, it was confirmed that a dysregulation of mitochondrial fission/fusion events greatly contributed to the reported trafficking phenotype. In conclusion, our study demonstrated, for the first time, that the mixture of MDMA and its metabolites, at concentrations relevant to the in vivo scenario, impaired mitochondrial trafficking and increased mitochondrial fragmentation in hippocampal neurons, thus providing a new insight in the context of "ecstasy"-induced neuronal injury.
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Affiliation(s)
- Daniel José Barbosa
- REQUIMTE (Rede de Química e Tecnologia), Toxicology Laboratory, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
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MDMA impairs mitochondrial neuronal trafficking in a Tau- and Mitofusin2/Drp1-dependent manner. Arch Toxicol 2014; 88:1561-72. [PMID: 24522274 DOI: 10.1007/s00204-014-1209-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 01/29/2014] [Indexed: 01/11/2023]
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Bereiter-Hahn J. Mitochondrial dynamics in aging and disease. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 127:93-131. [PMID: 25149215 DOI: 10.1016/b978-0-12-394625-6.00004-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mitochondria are self-replicating organelles but nevertheless strongly depend on supply coded in nuclear genes. They serve many physiological demands in living cells. Supply of the cytoplasm with ATP and engagement in Ca(2+) regulation belong to the main functions of mitochondria. In large eukaryotic cells, in particular in neurons, with their long dendrites and axons, mitochondria have to move to the sites of their action. This trafficking involves several motor molecules and mechanisms to sense the sites of requirements of mitochondria. With aging and as a consequence of some diseases, mitochondrial components may be rendered dysfunctional, and mtDNA mutations arise during the course of replication and by the action of reactive oxygen species. Mutants in motor molecules engaged in trafficking and in the machinery of fusion and fission are causing severe deficiencies on the cellular level; they support neurodegeneration and, thus, cause many diseases. Frequent fusion and fission events mediate the elimination of impaired parts from mitochondria which finally will be degraded by autophagosomes. Extensive fusion provides a basis for functional complementation. Mobility of proteins and small molecules within the mitochondria is necessary to reach the functional goals of fusion and fission, although cristae and a large fraction of proteins of the respiratory complexes proved to be stable for hours after fusion and perform slow exchange of material.
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Affiliation(s)
- Jürgen Bereiter-Hahn
- Institute for Cell Biology and Neurosciences, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
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Amadoro G, Corsetti V, Florenzano F, Atlante A, Ciotti MT, Mongiardi MP, Bussani R, Nicolin V, Nori SL, Campanella M, Calissano P. AD-linked, toxic NH2 human tau affects the quality control of mitochondria in neurons. Neurobiol Dis 2013; 62:489-507. [PMID: 24411077 DOI: 10.1016/j.nbd.2013.10.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 09/10/2013] [Accepted: 10/16/2013] [Indexed: 12/01/2022] Open
Abstract
Functional as well as structural alterations in mitochondria size, shape and distribution are precipitating, early events in progression of Alzheimer's Disease (AD). We reported that a 20-22kDa NH2-tau fragment (aka NH2htau), mapping between 26 and 230 amino acids of the longest human tau isoform, is detected in cellular and animal AD models and is neurotoxic in hippocampal neurons. The NH2htau -but not the physiological full-length protein- interacts with Aβ at human AD synapses and cooperates with it in inhibiting the mitochondrial ANT-1-dependent ADP/ATP exchange. Here we show that the NH2htau also adversely affects the interplay between the mitochondria dynamics and their selective autophagic clearance. Fragmentation and perinuclear mislocalization of mitochondria with smaller size and density are early found in dying NH2htau-expressing neurons. The specific effect of NH2htau on quality control of mitochondria is accompanied by (i) net reduction in their mass in correlation with a general Parkin-mediated remodeling of membrane proteome; (ii) their extensive association with LC3 and LAMP1 autophagic markers; (iii) bioenergetic deficits and (iv) in vitro synaptic pathology. These results suggest that NH2htau can compromise the mitochondrial biology thereby contributing to AD synaptic deficits not only by ANT-1 inactivation but also, indirectly, by impairing the quality control mechanism of these organelles.
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Affiliation(s)
- G Amadoro
- Institute of Translational Pharmacology (IFT), CNR, Via Fosso del Cavaliere 100-00133, Rome, Italy; European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65-00143, Rome, Italy.
| | - V Corsetti
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65-00143, Rome, Italy
| | - F Florenzano
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65-00143, Rome, Italy; Institute of Cellular Biology and Neurobiology (IBCN), CNR, IRCSS Fondazione Santa Lucia, Via del Fosso di Fiorano 64-65-00143, Rome, Italy
| | - A Atlante
- Insitute of Biomembrane and Bioenergetic (IBBE), CNR, Via Amendola 165/A-70126, Bari, Italy
| | - M T Ciotti
- Institute of Cellular Biology and Neurobiology (IBCN), CNR, IRCSS Fondazione Santa Lucia, Via del Fosso di Fiorano 64-65-00143, Rome, Italy
| | - M P Mongiardi
- Institute of Cellular Biology and Neurobiology (IBCN), CNR, IRCSS Fondazione Santa Lucia, Via del Fosso di Fiorano 64-65-00143, Rome, Italy
| | - R Bussani
- UCO Anatomy and Pathological Histology, Hospital of Cattinara, Strada di Fiume 447-34149, Trieste Italy
| | - V Nicolin
- University of Trieste, Clinical Department of Medical, Surgical and Health Science-section of Human Morphology, Via Manzoni 16-34138, Trieste, Italy
| | - S L Nori
- University of Salerno, Department of Pharmaceutical and Biomedical Sciences (FARMABIOMED), NANOMATES, Via Ponte don Melillo 1-85084, Fisciano (SA), Italy
| | - M Campanella
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65-00143, Rome, Italy; Department of Comparative Biomedical Sciences, The Royal Veterinary College, and Consortium for Mitochondrial Research, University College London, Royal College Street, NW1 0TU, United Kingdom
| | - P Calissano
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65-00143, Rome, Italy
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Cummins N, Bartlett CA, Archer M, Bartlett E, Hemmi JM, Harvey AR, Dunlop SA, Fitzgerald M. Changes to mitochondrial ultrastructure in optic nerve vulnerable to secondary degeneration in vivo are limited by irradiation at 670 nm. BMC Neurosci 2013; 14:98. [PMID: 24011177 PMCID: PMC3844486 DOI: 10.1186/1471-2202-14-98] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 09/03/2013] [Indexed: 11/10/2022] Open
Abstract
Background Traumatic injury to the central nervous system results in damage to tissue beyond the primary injury, termed secondary degeneration. Key events thought to be associated with secondary degeneration involve aspects of mitochondrial function which may be modulated by red/near-infrared irradiation therapy (R/NIR-IT), but precisely how mitochondria are affected in vivo has not been investigated. Secondary degeneration was modelled by transecting the dorsal aspect of the optic nerve in adult rats and mitochondrial ultrastructure in intact ventral optic nerve vulnerable to secondary degeneration investigated with transmission electron microscopy. Results Despite reported increases in fission following central nervous system injury, we saw no change in mitochondrial densities in optic nerve vulnerable to secondary degeneration in vivo. However, in axons, frequency distributions of mitochondrial profile areas showed higher cumulative probabilities of smaller mitochondrial profiles at day 1 after injury. Glial mitochondrial profiles did not exhibit changes in area, but a more elliptical mitochondrial shape was observed at both day 1 and 7 following injury. Importantly, mitochondrial autophagic profiles were observed at days 1 and 7 in optic nerve vulnerable to secondary degeneration in vivo. Citrate synthase activity was used as an additional measure of mitochondrial mass in ventral optic nerve and was decreased at day 7, whereas mitochondrial aconitase activity increased at day 1 and day 28 after injury in optic nerve vulnerable to secondary degeneration. R/NIR-IT has been used to treat the injured central nervous system, with reported improvements in oxidative metabolism suggesting mitochondrial involvement, but ultrastructural information is lacking. Here we show that R/NIR-IT of injured animals resulted in distributions of mitochondrial areas and shape not significantly different from control and significantly reduced mitochondrial autophagic profiles. R/NIR-IT also resulted in decreased citrate synthase activity (day 7) and increased aconitase activity (day 1) in optic nerve vulnerable to secondary degeneration. Conclusions These findings suggest that mitochondrial structure and activity of enzymes of the citric acid cycle are dynamically altered during secondary degeneration in vivo and R/NIR-IT may protect mitochondrial structure.
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Affiliation(s)
- Nadia Cummins
- Experimental and Regenerative Neurosciences, The University of Western Australia, Crawley 6009, WA, Australia.
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Vinsant S, Mansfield C, Jimenez-Moreno R, Del Gaizo Moore V, Yoshikawa M, Hampton TG, Prevette D, Caress J, Oppenheim RW, Milligan C. Characterization of early pathogenesis in the SOD1(G93A) mouse model of ALS: part II, results and discussion. Brain Behav 2013; 3:431-57. [PMID: 24381813 PMCID: PMC3869683 DOI: 10.1002/brb3.142] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 03/21/2013] [Accepted: 03/22/2013] [Indexed: 12/12/2022] Open
Abstract
Pathological events are well characterized in amyotrophic lateral sclerosis (ALS) mouse models, but review of the literature fails to identify a specific initiating event that precipitates disease pathology. There is now growing consensus in the field that axon and synapses are first cellular sites of degeneration, but controversy exists over whether axon and synapse loss is initiated autonomously at those sites or by pathology in the cell body, in nonneuronal cells or even in nonmotoneurons (MNs). Previous studies have identified pathological events in the mutant superoxide dismutase 1 (SOD1) models involving spinal cord, peripheral axons, neuromuscular junctions (NMJs), or muscle; however, few studies have systematically examined pathogenesis at multiple sites in the same study. We have performed ultrastructural examination of both central and peripheral components of the neuromuscular system in the SOD1(G93A) mouse model of ALS. Twenty percent of MNs undergo degeneration by P60, but NMJ innervation in fast fatigable muscles is reduced by 40% by P30. Gait alterations and muscle weakness were also found at P30. There was no change in axonal transport prior to initial NMJ denervation. Mitochondrial morphological changes are observed at P7 and become more prominent with disease progression. At P30 there was a significant decrease in excitatory axo-dendritic and axo-somatic synapses with an increase in C-type axo-somatic synapses. Our study examined early pathology in both peripheral and central neuromuscular system. The muscle denervation is associated with functional motor deficits and begins during the first postnatal month in SOD1(G93A) mice. Physiological dysfunction and pathology in the mitochondria of synapses and MN soma and dendrites occur, and disease onset in these animals begins more than 2 months earlier than originally thought. This information may be valuable for designing preclinical trials that are more likely to impact disease onset and progression.
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Affiliation(s)
- Sharon Vinsant
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - Carol Mansfield
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - Ramon Jimenez-Moreno
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | | | - Masaaki Yoshikawa
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | | | - David Prevette
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - James Caress
- Department of Neurology and the ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - Ronald W Oppenheim
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - Carol Milligan
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
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41
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Su YC, Qi X. Impairment of mitochondrial dynamics: a target for the treatment of neurological disorders? FUTURE NEUROLOGY 2013. [DOI: 10.2217/fnl.13.8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mitochondrial dysfunction has long been appreciated in the pathogenesis of various neurological disorders. However, the molecular basis underlying the decline in mitochondrial function is not fully understood. Mitochondria are highly dynamic organelles that frequently undergo fusion and fission. In healthy cells, the delicate balance between fusion and fission is required for maintaining normal mitochondrial and cellular function. However, under pathological conditions, the balance is disrupted, resulting in excessive mitochondrial fragmentation and mitochondrial dysfunction. The impaired fusion and fission processes can lead to apoptosis, necrosis and autophagic cell death and seem to play causal roles in the progression of acute and chronic neuronal injuries. In this article, important aspects of what is currently known about the molecular machinery regulating mitochondrial fission and fusion in mammalian cells is summarized. Special emphasis will be given to the consequences of disregulated mitochondrial morphology in the pathogenesis of neurological diseases.
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Affiliation(s)
- Yu-Chin Su
- Department of Physiology & Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Xin Qi
- Center for Mitochondrial Diseases, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, E516, Cleveland, OH, 44106-44970, USA
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Satori CP, Henderson MM, Krautkramer EA, Kostal V, Distefano MM, Arriaga EA. Bioanalysis of eukaryotic organelles. Chem Rev 2013; 113:2733-811. [PMID: 23570618 PMCID: PMC3676536 DOI: 10.1021/cr300354g] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Chad P. Satori
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Michelle M. Henderson
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Elyse A. Krautkramer
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Vratislav Kostal
- Tescan, Libusina trida 21, Brno, 623 00, Czech Republic
- Institute of Analytical Chemistry ASCR, Veveri 97, Brno, 602 00, Czech Republic
| | - Mark M. Distefano
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
| | - Edgar A. Arriaga
- Department of Chemistry, University of Minnesota, Twin Cities, Minneapolis, MN, USA, 55455
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43
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Breuer M, Koopman W, Koene S, Nooteboom M, Rodenburg R, Willems P, Smeitink J. The role of mitochondrial OXPHOS dysfunction in the development of neurologic diseases. Neurobiol Dis 2013; 51:27-34. [DOI: 10.1016/j.nbd.2012.03.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 02/04/2012] [Accepted: 03/01/2012] [Indexed: 12/12/2022] Open
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44
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Mitochondrial trafficking in neuropsychiatric diseases. Neurobiol Dis 2013; 51:66-71. [DOI: 10.1016/j.nbd.2012.06.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 06/07/2012] [Accepted: 06/22/2012] [Indexed: 12/31/2022] Open
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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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46
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Motility of astrocytic mitochondria is arrested by Ca2+-dependent interaction between mitochondria and actin filaments. Cell Calcium 2012. [PMID: 23177663 DOI: 10.1016/j.ceca.2012.10.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Motility of mitochondria, as well as their activity-dependent immobilization ("trapping"), is essential for neuronal function, but its regulation by cytoskeleton and relevance for glial cell signalling are unknown. Using time-lapse fluorescence imaging in rat cultured astrocytes, we evaluated the role of microtubules and actin filaments in motility of mitochondria in resting cells and during physiological or pathological Ca(2+) elevations. We found that mitochondria were significantly more aligned with microtubules than with actin filaments. Mitochondria were highly mobile under resting conditions at low intracellular free Ca(2+) concentrations ([Ca(2+)](i)). Activation of a moderate increase in [Ca(2+)](i) by either low-dose ionomycin or ATP immobilized mitochondria significantly but reversibly, without affecting mitochondrial morphology. A larger dose of ionomycin caused irreversible arrest and fragmentation of mitochondria. Disruption of microtubules completely arrested mitochondrial motility, while disruption of actin filaments had no effect on the basal mitochondrial motility at resting [Ca(2+)](i) levels but significantly reduced mitochondrial immobilization during [Ca(2+)](i) elevations. These results suggest that: (i) motility of astrocytic mitochondria is inversely related to [Ca(2+)](i), (ii) mitochondria require intact microtubules for their motility, and (iii) elevated [Ca(2+)](i) immobilizes mitochondria by strengthening their interaction with actin filaments.
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47
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Calkins DJ. Critical pathogenic events underlying progression of neurodegeneration in glaucoma. Prog Retin Eye Res 2012; 31:702-19. [PMID: 22871543 DOI: 10.1016/j.preteyeres.2012.07.001] [Citation(s) in RCA: 229] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 07/16/2012] [Accepted: 07/18/2012] [Indexed: 01/03/2023]
Abstract
Glaucoma is a common optic neuropathy with a complex etiology often linked to sensitivity to intraocular pressure. Though the precise mechanisms that mediate or transduce this sensitivity are not clear, the axon of the retinal ganglion cell appears to be vulnerable to disease-relevant stressors early in progression. One reason may be because the axon is generally thin for both its unmyelinated and myelinated segment and much longer than the thicker unmyelinated axons of other excitatory retinal neurons. This difference may predispose the axon to metabolic and oxidative injury, especially at distal sites where pre-synaptic terminals form connections in the brain. This idea is consistent with observations of early loss of anterograde transport at central targets and other signs of distal axonopathy that accompany physiological indicators of progression. Outright degeneration of the optic projection ensues after a critical period and, at least in animal models, is highly sensitive to cumulative exposure to elevated pressure in the eye. Stress emanating from the optic nerve head can induce not only distal axonopathy with aspects of dying back neuropathy, but also Wallerian degeneration of the optic nerve and tract and a proximal program involving synaptic and dendritic pruning in the retina. Balance between progressive and acute mechanisms likely varies with the level of stress placed on the unmyelinated axon as it traverses the nerve head, with more acute insult pushing the system toward quicker disassembly. A constellation of signaling factors likely contribute to the transduction of stress to the axon, so that degenerative events along the length of the optic projection progress in retinotopic fashion. This pattern leads to well-defined sectors of functional depletion, even at distal-most sites in the pathway. While ganglion cell somatic drop-out is later in progression, some evidence suggests that synaptic and dendritic pruning in the retina may be a more dynamic process. Structural persistence both in the retina and in central projection sites offers the possibility that intrinsic self-repair pathways counter pathogenic mechanisms to delay as long as possible outright loss of tissue.
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Affiliation(s)
- David J Calkins
- Department of Ophthalmology and Visual Sciences, The Vanderbilt Eye Institute, Vanderbilt University School of Medicine, 11435 MRB IV, 2215B Garland Avenue, Nashville, TN 37232, USA.
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48
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Abstract
Vigorous transport of cytoplasmic components along axons over substantial distances is crucial for the maintenance of neuron structure and function. The transport of mitochondria, which serves to distribute mitochondrial functions in a dynamic and non-uniform fashion, has attracted special interest in recent years following the discovery of functional connections among microtubules, motor proteins and mitochondria, and their influences on neurodegenerative diseases. Although the motor proteins that drive mitochondrial movement are now well characterized, the mechanisms by which anterograde and retrograde movement are coordinated with one another and with stationary axonal mitochondria are not yet understood. In this Commentary, we review why mitochondria move and how they move, focusing particularly on recent studies of transport regulation, which implicate control of motor activity by specific cell-signaling pathways, regulation of motor access to transport tracks and static microtubule-mitochondrion linkers. A detailed mechanism for modulating anterograde mitochondrial transport has been identified that involves Miro, a mitochondrial Ca(2+)-binding GTPase, which with associated proteins, can bind and control kinesin-1. Elements of the Miro complex also have important roles in mitochondrial fission-fusion dynamics, highlighting questions about the interdependence of biogenesis, transport, dynamics, maintenance and degradation.
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Affiliation(s)
- William M Saxton
- Department of Molecular Cell and Developmental Biology, University of California, Cruz, CA 95060, USA.
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Calì T, Ottolini D, Brini M. Mitochondrial Ca(2+) and neurodegeneration. Cell Calcium 2012; 52:73-85. [PMID: 22608276 PMCID: PMC3396847 DOI: 10.1016/j.ceca.2012.04.015] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 04/18/2012] [Accepted: 04/20/2012] [Indexed: 12/16/2022]
Abstract
Mitochondria are essential for ensuring numerous fundamental physiological processes such as cellular energy, redox balance, modulation of Ca2+ signaling and important biosynthetic pathways. They also govern the cell fate by participating in the apoptosis pathway. The mitochondrial shape, volume, number and distribution within the cells are strictly controlled. The regulation of these parameters has an impact on mitochondrial function, especially in the central nervous system, where trafficking of mitochondria is critical to their strategic intracellular distribution, presumably according to local energy demands. Thus, the maintenance of a healthy mitochondrial population is essential to avoid the impairment of the processes they regulate: for this purpose, cells have developed mechanisms involving a complex system of quality control to remove damaged mitochondria, or to renew them. Defects of these processes impair mitochondrial function and lead to disordered cell function, i.e., to a disease condition. Given the standard role of mitochondria in all cells, it might be expected that their dysfunction would give rise to similar defects in all tissues. However, damaged mitochondrial function has pleiotropic effects in multicellular organisms, resulting in diverse pathological conditions, ranging from cardiac and brain ischemia, to skeletal muscle myopathies to neurodegenerative diseases. In this review, we will focus on the relationship between mitochondrial (and cellular) derangements and Ca2+ dysregulation in neurodegenerative diseases, emphasizing the evidence obtained in genetic models. Common patterns, that recognize the derangement of Ca2+ and energy control as a causative factor, have been identified: advances in the understanding of the molecular regulation of Ca2+ homeostasis, and on the ways in which it could become perturbed in neurological disorders, may lead to the development of therapeutic strategies that modulate neuronal Ca2+ signaling.
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Affiliation(s)
- Tito Calì
- Department of Comparative Biomedicine and Food Science, University of Padova, Padova, Italy
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50
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Florenzano F. Localization of axonal motor molecules machinery in neurodegenerative disorders. Int J Mol Sci 2012; 13:5195-5206. [PMID: 22606038 PMCID: PMC3344274 DOI: 10.3390/ijms13045195] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Revised: 04/02/2012] [Accepted: 04/18/2012] [Indexed: 11/21/2022] Open
Abstract
Axonal transport and neuronal survival depend critically on active transport and axon integrity both for supplying materials and communication to different domains of the cell body. All these actions are executed through cytoskeleton, transport and regulatory elements that appear to be disrupted in neurodegenerative diseases. Motor-driven transport both supplies and clears distal cellular portions with proteins and organelles. This transport is especially relevant in projection and motor neurons, which have long axons to reach the farthest nerve endings. Thus, any disturbance of axonal transport may have severe consequences for neuronal function and survival. A growing body of literature indicates the presence of alterations to the motor molecules machinery, not only in expression levels and phosphorylation, but also in their subcellular distribution within populations of neurons, which are selectively affected in the course of neurodegenerative diseases. The implications of this altered subcellular localization and how this affects axon survival and neuronal death still remain poorly understood, although several hypotheses have been suggested. Furthermore, cytoskeleton and transport element localization can be selectively disrupted in some disorders suggesting that specific loss of the axonal functionality could be a primary hallmark of the disorder. This can lead to axon degeneration and neuronal death either directly, through the functional absence of essential axonal proteins, or indirectly, through failures in communication among different cellular domains. This review compares the localization of cytoskeleton and transport elements in some neurodegenerative disorders to ask what aspects may be essential for axon survival and neuronal death.
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Affiliation(s)
- Fulvio Florenzano
- Confocal Microscopy Unit, EBRI and S. Lucia Foundation, Via Fosso del Fiorano, 64/65-00143 Rome, Italy
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