151
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Faits MC, Zhang C, Soto F, Kerschensteiner D. Dendritic mitochondria reach stable positions during circuit development. eLife 2016; 5:e11583. [PMID: 26742087 PMCID: PMC4749546 DOI: 10.7554/elife.11583] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 12/30/2015] [Indexed: 01/07/2023] Open
Abstract
Mitochondria move throughout neuronal dendrites and localize to sites of energy demand. The prevailing view of dendritic mitochondria as highly motile organelles whose distribution is continually adjusted by neuronal activity via Ca(2+)-dependent arrests is based on observations in cultured neurons exposed to artificial stimuli. Here, we analyze the movements of mitochondria in ganglion cell dendrites in the intact retina. We find that whereas during development 30% of mitochondria are motile at any time, as dendrites mature, mitochondria all but stop moving and localize stably to synapses and branch points. Neither spontaneous nor sensory-evoked activity and Ca(2+) transients alter motility of dendritic mitochondria; and pathological hyperactivity in a mouse model of retinal degeneration elevates rather than reduces motility. Thus, our findings indicate that dendritic mitochondria reach stable positions during a critical developmental period of high motility, and challenge current views about the role of activity in regulating mitochondrial transport in dendrites.
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Affiliation(s)
- Michelle C Faits
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, United States.,Graduate Program in Developmental, Regenerative and Stem Cell Biology, Washington University School of Medicine, St. Louis, United States
| | - Chunmeng Zhang
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, United States
| | - Florentina Soto
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, United States
| | - Daniel Kerschensteiner
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, Saint Louis, United States.,Department of Neuroscience, Washington University School of Medicine, Saint Louis, United States.,Department of Biomedical Engineering, Washington University School of Medicine, Saint Louis, United States.,Hope Center for Neurological Disorders, Washington University School of Medicine, Saint Louis, United States
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152
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Kim B, Park J, Chang KT, Lee DS. Peroxiredoxin 5 prevents amyloid-beta oligomer-induced neuronal cell death by inhibiting ERK-Drp1-mediated mitochondrial fragmentation. Free Radic Biol Med 2016; 90:184-94. [PMID: 26582373 DOI: 10.1016/j.freeradbiomed.2015.11.015] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 10/19/2015] [Accepted: 11/10/2015] [Indexed: 11/29/2022]
Abstract
Alzheimer's disease (AD), a neurodegenerative disorder, is caused by amyloid-beta oligomers (AβOs). AβOs induce cell death by triggering oxidative stress and mitochondrial dysfunction. A recent study showed that AβO-induced oxidative stress is associated with extracellular signal-regulated kinase (ERK)-dynamin related protein 1 (Drp1)-mediated mitochondrial fission. Reactive oxygen species (ROS) are regulated by antioxidant enzymes, especially peroxiredoxins (Prxs) that scavenge H2O2. These enzymes inhibit neuronal cell death induced by various neurotoxic reagents. However, it is unclear whether Prx5, which is specifically expressed in neuronal cells, protects these cells from AβO-induced damage. In this study, we found that Prx5 expression was upregulated by AβO-induced oxidative stress and that Prx5 decreased ERK-Drp1-mediated mitochondrial fragmentation and apoptosis of HT-22 neuronal cells. Prx5 expression was affected by AβO, and amelioration of oxidative stress by N-acetyl-L-cysteine decreased AβO-induced Prx5 expression. Prx5 overexpression reduced ROS as well as RNS and apoptotic cell death but Prx5 knockdown did not. In addition, Prx5 overexpression ameliorated ERK-Drp1-mediated mitochondrial fragmentation but Prx5 knockdown did not. These results indicated that inducible Prx5 expression by AβO plays a key role in inhibiting both ERK-Drp1-induced mitochondrial fragmentation and neuronal cell death by regulating oxidative stress. Thus, Prx5 may be a new therapeutic agent for treating AD.
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Affiliation(s)
- Bokyung Kim
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Junghyung Park
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea
| | - Kyu-Tae Chang
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Chungcheongbuk-do, Republic of Korea
| | - Dong-Seok Lee
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea.
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153
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Tang BL. MIRO GTPases in Mitochondrial Transport, Homeostasis and Pathology. Cells 2015; 5:cells5010001. [PMID: 26729171 PMCID: PMC4810086 DOI: 10.3390/cells5010001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 12/22/2015] [Accepted: 12/24/2015] [Indexed: 01/08/2023] Open
Abstract
The evolutionarily-conserved mitochondrial Rho (MIRO) small GTPase is a Ras superfamily member with three unique features. It has two GTPase domains instead of the one found in other small GTPases, and it also has two EF hand calcium binding domains, which allow Ca2+-dependent modulation of its activity and functions. Importantly, it is specifically associated with the mitochondria and via a hydrophobic transmembrane domain, rather than a lipid-based anchor more commonly found in other small GTPases. At the mitochondria, MIRO regulates mitochondrial homeostasis and turnover. In metazoans, MIRO regulates mitochondrial transport and organization at cellular extensions, such as axons, and, in some cases, intercellular transport of the organelle through tunneling nanotubes. Recent findings have revealed a myriad of molecules that are associated with MIRO, particularly the kinesin adaptor Milton/TRAK, mitofusin, PINK1 and Parkin, as well as the endoplasmic reticulum-mitochondria encounter structure (ERMES) complex. The mechanistic aspects of the roles of MIRO and its interactors in mitochondrial homeostasis and transport are gradually being revealed. On the other hand, MIRO is also increasingly associated with neurodegenerative diseases that have roots in mitochondrial dysfunction. In this review, I discuss what is currently known about the cellular physiology and pathophysiology of MIRO functions.
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Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, MD7, 8 Medical Drive, Singapore 117597, Singapore.
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore.
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154
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Jodeiri Farshbaf M, Ghaedi K, Megraw TL, Curtiss J, Shirani Faradonbeh M, Vaziri P, Nasr-Esfahani MH. Does PGC1α/FNDC5/BDNF Elicit the Beneficial Effects of Exercise on Neurodegenerative Disorders? Neuromolecular Med 2015; 18:1-15. [PMID: 26611102 DOI: 10.1007/s12017-015-8370-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 08/22/2015] [Indexed: 12/20/2022]
Abstract
Neurodegenerative disorders such as Alzheimer's, Parkinson's and Huntington's diseases have high prevalence among the elderly. Many strategies have been established to alleviate the symptoms experienced by affected individuals. Recent studies have shown that exercise helps patients with neurological disorders to regain lost physical abilities. PGC1α/FNDC5/BDNF has emerged recently as a critical pathway for neuroprotection. PGC1α is a highly conserved co-activator of transcription factors that preserves and protects neurons against destruction. PGC1α regulates FNDC5 and its processed and secreted peptide Irisin, which has been proposed to play a critical role in energy expenditure and to promote neural differentiation of mouse embryonic stem cells. FNDC5 may also increase the expression of the neurotrophic factor BDNF, a neuroprotective agent, in the hippocampus. BDNF is secreted from hippocampus, amygdala, cerebral cortex and hypothalamus neurons and initiates intracellular signaling pathways through TrkB receptors. These pathways have positive feedback on CREB activities and lead to enhancement in PGC1α expression in neurons. Therefore, FNDC5 could behave as a key regulator in neuronal survival and development. This review presents recent findings on the PGC1α/FNDC5/BDNF pathway and its role in neuroprotection, and discusses the controversial promise of irisin as a mediator of the positive benefits of exercise.
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Affiliation(s)
- Mohammad Jodeiri Farshbaf
- Department of Cellular Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Royan Street, Salman Street, Khorasgan, Isfahan, 8165131378, Iran.,Department of Biology, School of Sciences, University of Isfahan, Hezarjerib Street, Azadi Square, Isfahan, 8174673441, Iran.,Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Kamran Ghaedi
- Department of Cellular Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Royan Street, Salman Street, Khorasgan, Isfahan, 8165131378, Iran. .,Department of Biology, School of Sciences, University of Isfahan, Hezarjerib Street, Azadi Square, Isfahan, 8174673441, Iran.
| | - Timothy L Megraw
- Department of Biomedical Sciences, Florida State University College of Medicine, West Call Street, Tallahassee, FL, 32306-4300, USA.
| | - Jennifer Curtiss
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Mahsa Shirani Faradonbeh
- Department of Biology, School of Sciences, University of Isfahan, Hezarjerib Street, Azadi Square, Isfahan, 8174673441, Iran
| | - Pooneh Vaziri
- Department of Biology, New Mexico State University, Las Cruces, NM, USA
| | - Mohammad Hossein Nasr-Esfahani
- Department of Cellular Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Royan Street, Salman Street, Khorasgan, Isfahan, 8165131378, Iran.
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155
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Marra MH, Tobias ZJ, Cohen HR, Glover G, Weissman TA. In Vivo Time-Lapse Imaging in the Zebrafish Lateral Line: A Flexible, Open-Ended Research Project for an Undergraduate Neurobiology Laboratory Course. JOURNAL OF UNDERGRADUATE NEUROSCIENCE EDUCATION : JUNE : A PUBLICATION OF FUN, FACULTY FOR UNDERGRADUATE NEUROSCIENCE 2015; 13:A215-A224. [PMID: 26240532 PMCID: PMC4521740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/01/2015] [Accepted: 06/02/2015] [Indexed: 06/04/2023]
Abstract
The lateral line sensory system in fish detects movements in the water and allows fish to respond to predators, prey, and other stimuli. As the lateral line forms in the first two days of zebrafish development, axons extend caudally along the lateral surface of the fish, eventually forming synapses with hair cells of neuromasts. Growing lateral line axons are located superficially under the skin and can be labeled in living zebrafish using fluorescent protein expression. This system provides a relatively straightforward approach for in vivo time-lapse imaging of neuronal development in an undergraduate setting. Here we describe an upper-level neurobiology laboratory module in which students investigate aspects of axonal development in the zebrafish lateral line system. Students learn to handle and image living fish, collect time-lapse videos of moving mitochondria, and quantitatively measure mitochondrial dynamics by generating and analyzing kymographs of their movements. Energy demands may differ between axons with extending growth cones versus axons that have already reached their targets and are forming synapses. Since relatively little is known about this process in developing lateral line axons, students generate and test their own hypotheses regarding how mitochondrial dynamics may differ at two different time points in axonal development. Students also learn to incorporate into their analysis a powerful yet accessible quantitative tool, the kymograph, which is used to graph movement over time. After students measure and quantify dynamics in living fish at 1 and 2 days post fertilization, this module extends into independent projects, in which students can expand their studies in a number of different, inquiry-driven directions. The project can also be pared down for courses that wish to focus solely on the quantitative analysis (without fish handling), or vice versa. This research module provides a useful approach for the design of open-ended laboratory research projects that integrate the scientific process into undergraduate Biology courses, as encouraged by the AAAS and NSF Vision and Change Initiative.
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Affiliation(s)
| | | | - Hannah R. Cohen
- Biology Department, Lewis & Clark College, Portland, OR 97219
| | - Greta Glover
- Biology Department, Reed College, Portland, OR 97202
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156
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Mitochondrial Dysfunction Contributes to the Pathogenesis of Alzheimer's Disease. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015. [PMID: 26221414 PMCID: PMC4499633 DOI: 10.1155/2015/509654] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease that affects millions of people worldwide. Currently, there is no effective treatment for AD, which indicates the necessity to understand the pathogenic mechanism of this disorder. Extracellular aggregates of amyloid precursor protein (APP), called Aβ peptide and neurofibrillary tangles (NFTs), formed by tau protein in the hyperphosphorylated form are considered the hallmarks of AD. Accumulative evidence suggests that tau pathology and Aβ affect neuronal cells compromising energy supply, antioxidant response, and synaptic activity. In this context, it has been showed that mitochondrial function could be affected by the presence of tau pathology and Aβ in AD. Mitochondria are essential for brain cells function and the improvement of mitochondrial activity contributes to preventing neurodegeneration. Several reports have suggested that mitochondria could be affected in terms of morphology, bioenergetics, and transport in AD. These defects affect mitochondrial health, which later will contribute to the pathogenesis of AD. In this review, we will discuss evidence that supports the importance of mitochondrial injury in the pathogenesis of AD and how studying these mechanisms could lead us to suggest new targets for diagnostic and therapeutic intervention against neurodegeneration.
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