1
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Dithmar S, Zare A, Salehi S, Briese M, Sendtner M. hnRNP R regulates mitochondrial movement and membrane potential in axons of motoneurons. Neurobiol Dis 2024; 193:106454. [PMID: 38408684 DOI: 10.1016/j.nbd.2024.106454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 02/12/2024] [Accepted: 02/23/2024] [Indexed: 02/28/2024] Open
Abstract
Axonal mitochondria defects are early events in the pathogenesis of motoneuron disorders such as spinal muscular atrophy and amyotrophic lateral sclerosis. The RNA-binding protein hnRNP R interacts with different motoneuron disease-related proteins such as SMN and TDP-43 and has important roles in axons of motoneurons, including axonal mRNA transport. However, whether hnRNP R also modulates axonal mitochondria is currently unknown. Here, we show that axonal mitochondria exhibit altered function and motility in hnRNP R-deficient motoneurons. Motoneurons lacking hnRNP R show decreased anterograde and increased retrograde transport of mitochondria in axons. Furthermore, hnRNP R-deficiency leads to mitochondrial hyperpolarization, caused by decreased complex I and reversed complex V activity within the respiratory chain. Taken together, our data indicate a role for hnRNP R in regulating transport and maintaining functionality of axonal mitochondria in motoneurons.
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Affiliation(s)
- Sophia Dithmar
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Abdolhossein Zare
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Saeede Salehi
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Michael Briese
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany.
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, Wuerzburg, Germany.
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2
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Wong DCS, Harvey JP, Jurkute N, Thomasy SM, Moosajee M, Yu-Wai-Man P, Gilhooley MJ. OPA1 Dominant Optic Atrophy: Pathogenesis and Therapeutic Targets. J Neuroophthalmol 2023; 43:464-474. [PMID: 37974363 PMCID: PMC10645107 DOI: 10.1097/wno.0000000000001830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Affiliation(s)
- David C. S. Wong
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
| | - Joshua P. Harvey
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
| | - Neringa Jurkute
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
| | - Sara M. Thomasy
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
| | - Mariya Moosajee
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
| | - Patrick Yu-Wai-Man
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
| | - Michael J. Gilhooley
- Department of Clinical Neurosciences (DCSW, PY-W-M), John van Geest Center for Brain Repair, University of Cambridge, Cambridge, United Kingdom; Cambridge Eye Unit (DCSW, PY-W-M), Addenbrooke's Hospital, Cambridge, United Kingdom; UCL Institute of Ophthalmology (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Moorfields Eye Hospital NHS Foundation Trust (JPH, NJ, MM, PY-W-M, MJG), London, United Kingdom; Department of Ophthalmology and Vision Science (SMT), School of Medicine, U.C. Davis, Sacramento, California; Department of Surgical and Radiological Sciences (SMT), School of Veterinary Medicine, U.C. Davis, California; Great Ormond Street Hospital (MM), London, United Kingdom; and The Francis Crick Institute (MM), London, United Kingdom
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3
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Chustecki JM, Etherington RD, Gibbs DJ, Johnston IG. Altered collective mitochondrial dynamics in the Arabidopsis msh1 mutant compromising organelle DNA maintenance. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:5428-5439. [PMID: 35662332 PMCID: PMC9467644 DOI: 10.1093/jxb/erac250] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 06/01/2022] [Indexed: 05/19/2023]
Abstract
Mitochondria form highly dynamic populations in the cells of plants (and almost all eukaryotes). The characteristics and benefits of this collective behaviour, and how it is influenced by nuclear features, remain to be fully elucidated. Here, we use a recently developed quantitative approach to reveal and analyse the physical and collective 'social' dynamics of mitochondria in an Arabidopsis msh1 mutant where the organelle DNA maintenance machinery is compromised. We use a newly created line combining the msh1 mutant with mitochondrially targeted green fluorescent protein (GFP), and characterize mitochondrial dynamics with a combination of single-cell time-lapse microscopy, computational tracking, and network analysis. The collective physical behaviour of msh1 mitochondria is altered from that of the wild type in several ways: mitochondria become less evenly spread, and networks of inter-mitochondrial encounters become more connected, with greater potential efficiency for inter-organelle exchange-reflecting a potential compensatory mechanism for the genetic challenge to the mitochondrial DNA population, supporting more inter-organelle exchange. We find that these changes are similar to those observed in friendly, where mitochondrial dynamics are altered by a physical perturbation, suggesting that this shift to higher connectivity may reflect a general response to mitochondrial challenges, where physical dynamics of mitochondria may be altered to control the genetic structure of the mtDNA population.
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Affiliation(s)
| | | | - Daniel J Gibbs
- School of Biosciences, University of Birmingham, Birmingham, UK
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4
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Ahluwalia M, Kumar M, Ahluwalia P, Rahimi S, Vender JR, Raju RP, Hess DC, Baban B, Vale FL, Dhandapani KM, Vaibhav K. Rescuing mitochondria in traumatic brain injury and intracerebral hemorrhages - A potential therapeutic approach. Neurochem Int 2021; 150:105192. [PMID: 34560175 PMCID: PMC8542401 DOI: 10.1016/j.neuint.2021.105192] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/18/2021] [Accepted: 09/20/2021] [Indexed: 02/07/2023]
Abstract
Mitochondria are dynamic organelles responsible for cellular energy production. Besides, regulating energy homeostasis, mitochondria are responsible for calcium homeostasis, signal transmission, and the fate of cellular survival in case of injury and pathologies. Accumulating reports have suggested multiple roles of mitochondria in neuropathologies, neurodegeneration, and immune activation under physiological and pathological conditions. Mitochondrial dysfunction, which occurs at the initial phase of brain injury, involves oxidative stress, inflammation, deficits in mitochondrial bioenergetics, biogenesis, transport, and autophagy. Thus, development of targeted therapeutics to protect mitochondria may improve functional outcomes following traumatic brain injury (TBI) and intracerebral hemorrhages (ICH). In this review, we summarize mitochondrial dysfunction related to TBI and ICH, including the mechanisms involved, and discuss therapeutic approaches with special emphasis on past and current clinical trials.
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Affiliation(s)
- Meenakshi Ahluwalia
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA.
| | - Manish Kumar
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Pankaj Ahluwalia
- Department of Pathology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Scott Rahimi
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - John R Vender
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Raghavan P Raju
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - David C Hess
- Department of Neurology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Babak Baban
- Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Fernando L Vale
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Krishnan M Dhandapani
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Kumar Vaibhav
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA; Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta, GA, USA.
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5
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Zinsmaier KE. Mitochondrial Miro GTPases coordinate mitochondrial and peroxisomal dynamics. Small GTPases 2021; 12:372-398. [PMID: 33183150 PMCID: PMC8583064 DOI: 10.1080/21541248.2020.1843957] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 10/22/2020] [Accepted: 10/26/2020] [Indexed: 12/18/2022] Open
Abstract
Mitochondria and peroxisomes are highly dynamic, multifunctional organelles. Both perform key roles for cellular physiology and homoeostasis by mediating bioenergetics, biosynthesis, and/or signalling. To support cellular function, they must be properly distributed, of proper size, and be able to interact with other organelles. Accumulating evidence suggests that the small atypical GTPase Miro provides a central signalling node to coordinate mitochondrial as well as peroxisomal dynamics. In this review, I summarize our current understanding of Miro-dependent functions and molecular mechanisms underlying the proper distribution, size and function of mitochondria and peroxisomes.
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Affiliation(s)
- Konrad E. Zinsmaier
- Departments of Neuroscience and Molecular and Cellular Biology, University of Arizona, Tucson, AZ, USA
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6
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Lenaers G, Neutzner A, Le Dantec Y, Jüschke C, Xiao T, Decembrini S, Swirski S, Kieninger S, Agca C, Kim US, Reynier P, Yu-Wai-Man P, Neidhardt J, Wissinger B. Dominant optic atrophy: Culprit mitochondria in the optic nerve. Prog Retin Eye Res 2021; 83:100935. [PMID: 33340656 DOI: 10.1016/j.preteyeres.2020.100935] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/05/2020] [Accepted: 12/09/2020] [Indexed: 12/14/2022]
Abstract
Dominant optic atrophy (DOA) is an inherited mitochondrial disease leading to specific degeneration of retinal ganglion cells (RGCs), thus compromising transmission of visual information from the retina to the brain. Usually, DOA starts during childhood and evolves to poor vision or legal blindness, affecting the central vision, whilst sparing the peripheral visual field. In 20% of cases, DOA presents as syndromic disorder, with secondary symptoms affecting neuronal and muscular functions. Twenty years ago, we demonstrated that heterozygous mutations in OPA1 are the most frequent molecular cause of DOA. Since then, variants in additional genes, whose functions in many instances converge with those of OPA1, have been identified by next generation sequencing. OPA1 encodes a dynamin-related GTPase imported into mitochondria and located to the inner membrane and intermembrane space. The many OPA1 isoforms, resulting from alternative splicing of three exons, form complex homopolymers that structure mitochondrial cristae, and contribute to fusion of the outer membrane, thus shaping the whole mitochondrial network. Moreover, OPA1 is required for oxidative phosphorylation, maintenance of mitochondrial genome, calcium homeostasis and regulation of apoptosis, thus making OPA1 the Swiss army-knife of mitochondria. Understanding DOA pathophysiology requires the understanding of RGC peculiarities with respect to OPA1 functions. Besides the tremendous energy requirements of RGCs to relay visual information from the eye to the brain, these neurons present unique features related to their differential environments in the retina, and to the anatomical transition occurring at the lamina cribrosa, which parallel major adaptations of mitochondrial physiology and shape, in the pre- and post-laminar segments of the optic nerve. Three DOA mouse models, with different Opa1 mutations, have been generated to study intrinsic mechanisms responsible for RGC degeneration, and these have further revealed secondary symptoms related to mitochondrial dysfunctions, mirroring the more severe syndromic phenotypes seen in a subgroup of patients. Metabolomics analyses of cells, mouse organs and patient plasma mutated for OPA1 revealed new unexpected pathophysiological mechanisms related to mitochondrial dysfunction, and biomarkers correlated quantitatively to the severity of the disease. Here, we review and synthesize these data, and propose different approaches for embracing possible therapies to fulfil the unmet clinical needs of this disease, and provide hope to affected DOA patients.
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Affiliation(s)
- Guy Lenaers
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France.
| | - Albert Neutzner
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Ophthalmology University Hospital Basel, University of Basel, Basel, Switzerland.
| | - Yannick Le Dantec
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France
| | - Christoph Jüschke
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Ting Xiao
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Sarah Decembrini
- Department of Biomedicine, University Hospital Basel, University of Basel, Basel, Switzerland; Department of Ophthalmology University Hospital Basel, University of Basel, Basel, Switzerland
| | - Sebastian Swirski
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Sinja Kieninger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Cavit Agca
- Molecular Biology, Genetics and Bioengineering Program, Sabanci University, Istanbul, Turkey; Nanotechnology Research and Application Center (SUNUM), Sabanci University, Istanbul, Turkey
| | - Ungsoo S Kim
- Kim's Eye Hospital, Seoul, South Korea; Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital, London, UK
| | - Pascal Reynier
- MitoLab Team, UMR CNRS 6015 - INSERM U1083, Institut MitoVasc, Angers University and Hospital, Angers, France; Department of Biochemistry, University Hospital of Angers, Angers, France
| | - Patrick Yu-Wai-Man
- Cambridge Centre for Brain Repair and MRC Mitochondrial Biology Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK; Cambridge Eye Unit, Addenbrooke's Hospital, Cambridge University Hospitals, Cambridge, UK; Moorfields Eye Hospital, London, UK; UCL Institute of Ophthalmology, University College London, London, UK
| | - John Neidhardt
- Human Genetics, Faculty VI - School of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University Oldenburg, Oldenburg, Germany.
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany.
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7
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Chustecki JM, Gibbs DJ, Bassel GW, Johnston IG. Network analysis of Arabidopsis mitochondrial dynamics reveals a resolved tradeoff between physical distribution and social connectivity. Cell Syst 2021; 12:419-431.e4. [PMID: 34015261 PMCID: PMC8136767 DOI: 10.1016/j.cels.2021.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 02/22/2021] [Accepted: 04/13/2021] [Indexed: 11/27/2022]
Abstract
Mitochondria in plant cells exist largely as individual organelles which move, colocalize, and interact, but the cellular priorities addressed by these dynamics remain incompletely understood. Here, we elucidate these principles by studying the dynamic "social networks" of mitochondria in Arabidopsis thaliana wildtype and mutants, describing the colocalization of individuals over time. We combine single-cell live imaging of hypocotyl mitochondrial dynamics with individual-based modeling and network analysis. We identify an inevitable tradeoff between mitochondrial physical priorities (an even cellular distribution of mitochondria) and “social” priorities (individuals interacting, to facilitate the exchange of chemicals and information). This tradeoff results in a tension between maintaining mitochondrial spacing and facilitating colocalization. We find that plant cells resolve this tension to favor efficient networks with high potential for exchanging contents. We suggest that this combination of physical modeling coupled to experimental data through network analysis can shed light on the fundamental principles underlying these complex organelle dynamics. A record of this paper’s transparent peer review process is included in the supplemental information. Dynamic social networks of plant mitochondria reflect physical organellar encounters Network analysis and modeling show priorities and tradeoffs for mitochondrial motion Mitochondria in plant cells trade off physical spacing against social connectivity Plant cells favor efficient networks with high potential for information exchange
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Affiliation(s)
| | - Daniel J Gibbs
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - George W Bassel
- Department of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Iain G Johnston
- Department of Mathematics, University of Bergen, Realfagbygget, Bergen 5007, Norway; Computational Biology Unit, University of Bergen, Høyteknologisenteret i Bergen, Bergen 5008, Norway.
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8
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Wang B, Huang M, Shang D, Yan X, Zhao B, Zhang X. Mitochondrial Behavior in Axon Degeneration and Regeneration. Front Aging Neurosci 2021; 13:650038. [PMID: 33762926 PMCID: PMC7982458 DOI: 10.3389/fnagi.2021.650038] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 02/18/2021] [Indexed: 12/19/2022] Open
Abstract
Mitochondria are organelles responsible for bioenergetic metabolism, calcium homeostasis, and signal transmission essential for neurons due to their high energy consumption. Accumulating evidence has demonstrated that mitochondria play a key role in axon degeneration and regeneration under physiological and pathological conditions. Mitochondrial dysfunction occurs at an early stage of axon degeneration and involves oxidative stress, energy deficiency, imbalance of mitochondrial dynamics, defects in mitochondrial transport, and mitophagy dysregulation. The restoration of these defective mitochondria by enhancing mitochondrial transport, clearance of reactive oxidative species (ROS), and improving bioenergetic can greatly contribute to axon regeneration. In this paper, we focus on the biological behavior of axonal mitochondria in aging, injury (e.g., traumatic brain and spinal cord injury), and neurodegenerative diseases (Alzheimer's disease, AD; Parkinson's disease, PD; Amyotrophic lateral sclerosis, ALS) and consider the role of mitochondria in axon regeneration. We also compare the behavior of mitochondria in different diseases and outline novel therapeutic strategies for addressing abnormal mitochondrial biological behavior to promote axonal regeneration in neurological diseases and injuries.
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Affiliation(s)
- Biyao Wang
- The VIP Department, School and Hospital of Stomatology, China Medical University, Liaoning Provincial Key Laboratory of Oral Diseases, Shenyang, China
| | - Minghao Huang
- Center of Implant Dentistry, School and Hospital of Stomatology, China Medical University, Liaoning Provincial Key Laboratory of Oral Diseases, Shenyang, China
| | - Dehao Shang
- Center of Implant Dentistry, School and Hospital of Stomatology, China Medical University, Liaoning Provincial Key Laboratory of Oral Diseases, Shenyang, China
| | - Xu Yan
- The VIP Department, School and Hospital of Stomatology, China Medical University, Liaoning Provincial Key Laboratory of Oral Diseases, Shenyang, China
| | - Baohong Zhao
- Center of Implant Dentistry, School and Hospital of Stomatology, China Medical University, Liaoning Provincial Key Laboratory of Oral Diseases, Shenyang, China
| | - Xinwen Zhang
- Center of Implant Dentistry, School and Hospital of Stomatology, China Medical University, Liaoning Provincial Key Laboratory of Oral Diseases, Shenyang, China
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9
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Abstract
Mitochondria are signaling hubs responsible for the generation of energy through oxidative phosphorylation, the production of key metabolites that serve the bioenergetic and biosynthetic needs of the cell, calcium (Ca2+) buffering and the initiation/execution of apoptosis. The ability of mitochondria to coordinate this myriad of functions is achieved through the exquisite regulation of fundamental dynamic properties, including remodeling of the mitochondrial network via fission and fusion, motility and mitophagy. In this Review, we summarize the current understanding of the mechanisms by which these dynamic properties of the mitochondria support mitochondrial function, review their impact on human cortical development and highlight areas in need of further research.
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Affiliation(s)
- Tierney Baum
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Vivian Gama
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Center for Stem Cell Biology, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Ingram Cancer Center, Vanderbilt University, Nashville, TN 37232, USA
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10
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Membrane Curvature, Trans-Membrane Area Asymmetry, Budding, Fission and Organelle Geometry. Int J Mol Sci 2020; 21:ijms21207594. [PMID: 33066582 PMCID: PMC7590041 DOI: 10.3390/ijms21207594] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 10/08/2020] [Accepted: 10/09/2020] [Indexed: 01/02/2023] Open
Abstract
In biology, the modern scientific fashion is to mostly study proteins. Much less attention is paid to lipids. However, lipids themselves are extremely important for the formation and functioning of cellular membrane organelles. Here, the role of the geometry of the lipid bilayer in regulation of organelle shape is analyzed. It is proposed that during rapid shape transition, the number of lipid heads and their size (i.e., due to the change in lipid head charge) inside lipid leaflets modulates the geometrical properties of organelles, in particular their membrane curvature. Insertion of proteins into a lipid bilayer and the shape of protein trans-membrane domains also affect the trans-membrane asymmetry between surface areas of luminal and cytosol leaflets of the membrane. In the cases where lipid molecules with a specific shape are not predominant, the shape of lipids (cylindrical, conical, or wedge-like) is less important for the regulation of membrane curvature, due to the flexibility of their acyl chains and their high ability to diffuse.
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11
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Mechanisms and roles of mitochondrial localisation and dynamics in neuronal function. Neuronal Signal 2020; 4:NS20200008. [PMID: 32714603 PMCID: PMC7373250 DOI: 10.1042/ns20200008] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 01/23/2023] Open
Abstract
Neurons are highly polarised, complex and incredibly energy intensive cells, and their demand for ATP during neuronal transmission is primarily met by oxidative phosphorylation by mitochondria. Thus, maintaining the health and efficient function of mitochondria is vital for neuronal integrity, viability and synaptic activity. Mitochondria do not exist in isolation, but constantly undergo cycles of fusion and fission, and are actively transported around the neuron to sites of high energy demand. Intriguingly, axonal and dendritic mitochondria exhibit different morphologies. In axons mitochondria are small and sparse whereas in dendrites they are larger and more densely packed. The transport mechanisms and mitochondrial dynamics that underlie these differences, and their functional implications, have been the focus of concerted investigation. Moreover, it is now clear that deficiencies in mitochondrial dynamics can be a primary factor in many neurodegenerative diseases. Here, we review the role that mitochondrial dynamics play in neuronal function, how these processes support synaptic transmission and how mitochondrial dysfunction is implicated in neurodegenerative disease.
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12
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Trevisan T, Pendin D, Montagna A, Bova S, Ghelli AM, Daga A. Manipulation of Mitochondria Dynamics Reveals Separate Roles for Form and Function in Mitochondria Distribution. Cell Rep 2019; 23:1742-1753. [PMID: 29742430 DOI: 10.1016/j.celrep.2018.04.017] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 03/01/2018] [Accepted: 04/02/2018] [Indexed: 01/09/2023] Open
Abstract
Mitochondria shape is controlled by membrane fusion and fission mediated by mitofusins, Opa1, and Drp1, whereas mitochondrial motility relies on microtubule motors. These processes govern mitochondria subcellular distribution, whose defects are emphasized in neurons because of their polarized structure. We have studied how perturbation of the fusion/fission balance affects mitochondria distribution in Drosophila axons. Knockdown of Marf or Opa1 resulted in progressive loss of distal mitochondria and in a distinct oxidative phosphorylation and membrane potential deficit. Downregulation of Drp1 rescued the lethality and bioenergetic defect caused by neuronal Marf RNAi, but induced only a modest restoration of axonal mitochondria distribution. Surprisingly, Drp1 knockdown rescued fragmentation and fully restored aberrant distribution of axonal mitochondria produced by Opa1 RNAi; however, Drp1 knockdown did not improve viability or mitochondria function. Our data show that proper morphology is critical for proper axonal mitochondria distribution independent of bioenergetic efficiency. The health of neurons largely depends on mitochondria function, but does not depend on shape or distribution.
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Affiliation(s)
- Tatiana Trevisan
- Laboratory of Molecular Biology, Scientific Institute IRCCS E. Medea, Bosisio Parini, Lecco, Italy
| | - Diana Pendin
- Laboratory of Molecular Biology, Scientific Institute IRCCS E. Medea, Bosisio Parini, Lecco, Italy
| | - Aldo Montagna
- Laboratory of Molecular Biology, Scientific Institute IRCCS E. Medea, Bosisio Parini, Lecco, Italy
| | - Sergio Bova
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
| | - Anna Maria Ghelli
- Department of Pharmacy and Biotechnology, University of Bologna, 40127 Bologna, Italy
| | - Andrea Daga
- Laboratory of Molecular Biology, Scientific Institute IRCCS E. Medea, Bosisio Parini, Lecco, Italy.
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High-glucose Induced Mitochondrial Dynamics Disorder of Spinal Cord Neurons in Diabetic Rats and its Effect on Mitochondrial Spatial Distribution. Spine (Phila Pa 1976) 2019; 44:E715-E722. [PMID: 30601355 DOI: 10.1097/brs.0000000000002952] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A randomized, double-blind, controlled trial. OBJECTIVE Few studies have investigated the changes in mitochondrial dynamics in spinal cord neurons. Meanwhile, the distribution of mitochondria in axons remains unclear. In the present study, the investigators attempted to clarify these questions and focused in observing the changes in mitochondrial spatial distribution under a high-glucose environment. SUMMARY OF BACKGROUND DATA Mitochondrial dynamics disorder is one of the main mechanisms that lead to nervous system diseases due to its adverse effects on mitochondrial morphology, function, and axon distribution. High-glucose stress can promote the increase in mitochondrial fission of various types of cells. METHODS The lumbar spinal cord of type 1 diabetic Sprague-Dawley rats at 4 weeks was observed. VSC4.1 cells were cultured and divided into three groups: normal control group, high-glucose intervention group, and high-glucose intervention combined with mitochondrial fission inhibitor Mdivi-1 intervention group. Immunohistochemistry and immunofluorescence methods were used to detect the expression of mitochondrial marker VDAC-1 in the spinal cord. An electron microscope was used to observe the number, structure, and distribution of mitochondria. Western blot was used to detect VDAC-1, fusion protein MFN1, MFN2, and OPA1, and fission protein FIS1 and DRP1. Living cell mitochondrial staining was performed using MitoTracker. Laser confocal microscopy and an Olympus live cell workstation were used to observe the mitochondrial changes. RESULTS The mitochondrial dynamics of spinal cord related neurons under an acute high-glucose environment were significantly unbalanced, including a reduction of fusion and increase of fission. Hence, mitochondrial fission has the absolute advantage. The total number of mitochondria in neuronal axons significantly decreased. CONCLUSION Increased mitochondrial fission and abnormal distribution occurred in spinal cord related neurons in a high-glucose environment. Mdivi-1 could significantly improve these disorders of mitochondria in VSC4.1 cells. Mitochondrial division inhibitors had a positive significance on diabetic neuropathy. LEVEL OF EVIDENCE N/A.
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14
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Sun J, Tian M, Lin W. A two-photon excited red-emissive probe for imaging mitochondria with high fidelity and its application in monitoring mitochondrial depolarization via FRET. Analyst 2019; 144:2387-2392. [DOI: 10.1039/c9an00076c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Two-photon red-emissive fluorescent probes for imaging mitochondria with high-fidelity have been constructed, and mitochondrial depolarization has been visualized with the probe.
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Affiliation(s)
- Jie Sun
- Institute of Fluorescent Probes for Biological Imaging
- School of Chemistry and Chemical Engineering
- School of Materials Science and Engineering
- University of Jinan
- Jinan
| | - Minggang Tian
- Institute of Fluorescent Probes for Biological Imaging
- School of Chemistry and Chemical Engineering
- School of Materials Science and Engineering
- University of Jinan
- Jinan
| | - Weiying Lin
- Institute of Fluorescent Probes for Biological Imaging
- School of Chemistry and Chemical Engineering
- School of Materials Science and Engineering
- University of Jinan
- Jinan
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15
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Chai X, Ba Q, Yang G. Characterizing robustness and sensitivity of convolutional neural networks for quantitative analysis of mitochondrial morphology. QUANTITATIVE BIOLOGY 2018. [DOI: 10.1007/s40484-018-0156-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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16
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Mariano V, Domínguez-Iturza N, Neukomm LJ, Bagni C. Maintenance mechanisms of circuit-integrated axons. Curr Opin Neurobiol 2018; 53:162-173. [PMID: 30241058 DOI: 10.1016/j.conb.2018.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Accepted: 08/14/2018] [Indexed: 12/21/2022]
Abstract
Adult, circuit-integrated neurons must be maintained and supported for the life span of their host. The attenuation of either maintenance or plasticity leads to impaired circuit function and ultimately to neurodegenerative disorders. Over the last few years, significant discoveries of molecular mechanisms were made that mediate the formation and maintenance of axons. Here, we highlight intrinsic and extrinsic mechanisms that ensure the health and survival of axons. We also briefly discuss examples of mutations associated with impaired axonal maintenance identified in specific neurological conditions. A better understanding of these mechanisms will therefore help to define targets for therapeutic interventions.
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Affiliation(s)
- Vittoria Mariano
- Department of Fundamental Neurosciences, University of Lausanne, Switzerland; Department of Neurosciences KU Leuven, VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Nuria Domínguez-Iturza
- Department of Fundamental Neurosciences, University of Lausanne, Switzerland; Department of Neurosciences KU Leuven, VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Lukas J Neukomm
- Department of Fundamental Neurosciences, University of Lausanne, Switzerland.
| | - Claudia Bagni
- Department of Fundamental Neurosciences, University of Lausanne, Switzerland; Department of Biomedicine and Prevention, University of Rome Tor Vergata, Italy.
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17
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Seong E, Insolera R, Dulovic M, Kamsteeg EJ, Trinh J, Brüggemann N, Sandford E, Li S, Ozel AB, Li JZ, Jewett T, Kievit AJ, Münchau A, Shakkottai V, Klein C, Collins C, Lohmann K, van de Warrenburg BP, Burmeister M. Mutations in VPS13D lead to a new recessive ataxia with spasticity and mitochondrial defects. Ann Neurol 2018; 83:1075-1088. [PMID: 29604224 PMCID: PMC6105379 DOI: 10.1002/ana.25220] [Citation(s) in RCA: 105] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 03/11/2018] [Accepted: 03/19/2018] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To identify novel causes of recessive ataxias, including spinocerebellar ataxia with saccadic intrusions, spastic ataxias, and spastic paraplegia. METHODS In an international collaboration, we independently performed exome sequencing in 7 families with recessive ataxia and/or spastic paraplegia. To evaluate the role of VPS13D mutations, we evaluated a Drosophila knockout model and investigated mitochondrial function in patient-derived fibroblast cultures. RESULTS Exome sequencing identified compound heterozygous mutations in VPS13D on chromosome 1p36 in all 7 families. This included a large family with 5 affected siblings with spinocerebellar ataxia with saccadic intrusions (SCASI), or spinocerebellar ataxia, recessive, type 4 (SCAR4). Linkage to chromosome 1p36 was found in this family with a logarithm of odds score of 3.1. The phenotypic spectrum in our 12 patients was broad. Although most presented with ataxia, additional or predominant spasticity was present in 5 patients. Disease onset ranged from infancy to 39 years, and symptoms were slowly progressive and included loss of independent ambulation in 5. All but 2 patients carried a loss-of-function (nonsense or splice site) mutation on one and a missense mutation on the other allele. Knockdown or removal of Vps13D in Drosophila neurons led to changes in mitochondrial morphology and impairment in mitochondrial distribution along axons. Patient fibroblasts showed altered morphology and functionality including reduced energy production. INTERPRETATION Our study demonstrates that compound heterozygous mutations in VPS13D cause movement disorders along the ataxia-spasticity spectrum, making VPS13D the fourth VPS13 paralog involved in neurological disorders. Ann Neurol 2018.
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Affiliation(s)
- Eunju Seong
- Molecular & Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, MI 48109, USA
| | - Ryan Insolera
- Department of Molecular, Cellular, and Developmental Biology,
University of Michigan, Ann Arbor, MI 48109, USA
| | - Marija Dulovic
- Institute of Neurogenetics, University of Lübeck,
Germany
| | - Erik-Jan Kamsteeg
- Department of Human Genetics, Radboud University Medical Centre,
Nijmegen, The Netherlands
| | - Joanne Trinh
- Institute of Neurogenetics, University of Lübeck,
Germany
| | | | - Erin Sandford
- Molecular & Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, MI 48109, USA
| | | | - Ayse Bilge Ozel
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
48109, USA
| | - Jun Z. Li
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
48109, USA
- Department of Computational Medicine & Bioinformatics,
University of Michigan, Ann Arbor, MI 48109, USA
| | - Tamison Jewett
- Department of Pediatrics, Section on Medical Genetics, Wake Forest
School of Medicine, Winston-Salem, North Carolina, USA
| | | | | | - Vikram Shakkottai
- Departments of Neurology and of Molecular and Integrative
Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Catherine Collins
- Department of Molecular, Cellular, and Developmental Biology,
University of Michigan, Ann Arbor, MI 48109, USA
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck,
Germany
| | - Bart P. van de Warrenburg
- Department of Neurology, Donders Institute for Brain, Cognition and
Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Margit Burmeister
- Molecular & Behavioral Neuroscience Institute, University of
Michigan, Ann Arbor, MI 48109, USA
- Department of Human Genetics, University of Michigan, Ann Arbor, MI
48109, USA
- Department of Computational Medicine & Bioinformatics,
University of Michigan, Ann Arbor, MI 48109, USA
- Department of Psychiatry, University of Michigan, Ann Arbor, MI
48109, USA
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18
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Transitional correlation between inner-membrane potential and ATP levels of neuronal mitochondria. Sci Rep 2018; 8:2993. [PMID: 29445117 PMCID: PMC5813116 DOI: 10.1038/s41598-018-21109-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/30/2018] [Indexed: 12/11/2022] Open
Abstract
The importance of highly active mitochondria and their contribution to neuronal function has been of recent interest. In most cases, however, mitochondrial activity is estimated using measurements of mitochondrial inner membrane potential (IMPmito), and little is known about the dynamics of native mitochondrial ATP (ATPmito). This study conducted simultaneous imaging of IMPmito and ATPmito in neurons to explore their behaviour and their correlation during physiological mitochondrial/neuronal activity. We found that mitochondrial size, transport velocity and transport direction are not dependent on ATPmito or IMPmito. However, changes in ATPmito and IMPmito during mitochondrial fission/fusion were found; IMPmito depolarized via mitochondrial fission and hyperpolarized via fusion, and ATPmito levels increased after fusion. Because the density of mitochondria is higher in growth cones (GCs) than in axonal processes, integrated ATPmito signals (density × ATPmito) were higher in GCs. This integrated signal in GCs correlated with axonal elongation. However, while the averaged IMPmito was relatively hyperpolarized in GCs, there was no correlation between IMPmito in GCs and axonal elongation. A detailed time-course analysis performed to clarify the reason for these discrepancies showed that IMPmito and ATPmito levels did not always correlate accurately; rather, there were several correlation patterns that changed over time.
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19
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Melkov A, Abdu U. Regulation of long-distance transport of mitochondria along microtubules. Cell Mol Life Sci 2018; 75:163-176. [PMID: 28702760 PMCID: PMC11105322 DOI: 10.1007/s00018-017-2590-1] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/05/2017] [Accepted: 07/06/2017] [Indexed: 11/29/2022]
Abstract
Mitochondria are cellular organelles of crucial importance, playing roles in cellular life and death. In certain cell types, such as neurons, mitochondria must travel long distances so as to meet metabolic demands of the cell. Mitochondrial movement is essentially microtubule (MT) based and is executed by two main motor proteins, Dynein and Kinesin. The organization of the cellular MT network and the identity of motors dictate mitochondrial transport. Tight coupling between MTs, motors, and the mitochondria is needed for the organelle precise localization. Two adaptor proteins are involved directly in mitochondria-motor coupling, namely Milton known also as TRAK, which is the motor adaptor, and Miro, which is the mitochondrial protein. Here, we discuss the active mitochondria transport process, as well as motor-mitochondria coupling in the context of MT organization in different cell types. We focus on mitochondrial trafficking in different cell types, specifically neurons, migrating cells, and polarized epithelial cells.
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Affiliation(s)
- Anna Melkov
- Department of Life Sciences, Ben-Gurion University, 8410500, Beersheba, Israel
| | - Uri Abdu
- Department of Life Sciences, Ben-Gurion University, 8410500, Beersheba, Israel.
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20
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Smith GM, Gallo G. The role of mitochondria in axon development and regeneration. Dev Neurobiol 2017; 78:221-237. [PMID: 29030922 DOI: 10.1002/dneu.22546] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/12/2017] [Accepted: 10/08/2017] [Indexed: 12/26/2022]
Abstract
Mitochondria are dynamic organelles that undergo transport, fission, and fusion. The three main functions of mitochondria are to generate ATP, buffer cytosolic calcium, and generate reactive oxygen species. A large body of evidence indicates that mitochondria are either primary targets for neurological disease states and nervous system injury, or are major contributors to the ensuing pathologies. However, the roles of mitochondria in the development and regeneration of axons have just begun to be elucidated. Advances in the understanding of the functional roles of mitochondria in neurons had been largely impeded by insufficient knowledge regarding the molecular mechanisms that regulate mitochondrial transport, stalling, fission/fusion, and a paucity of approaches to image and analyze mitochondria in living axons at the level of the single mitochondrion. However, technical advances in the imaging and analysis of mitochondria in living neurons and significant insights into the mechanisms that regulate mitochondrial dynamics have allowed the field to advance. Mitochondria have now been attributed important roles in the mechanism of axon extension, regeneration, and axon branching. The availability of new experimental tools is expected to rapidly increase our understanding of the functions of axonal mitochondria during both development and later regenerative attempts. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 221-237, 2018.
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Affiliation(s)
- George M Smith
- Department of Neuroscience, Temple University, Lewis Katz School of Medicine, Philadelphia, Pennsylvania, 19140.,Shriners Hospitals Pediatric Research Center, Temple University, Lewis Katz School of Medicine, Philadelphia, Pennsylvania, 19140
| | - Gianluca Gallo
- Department of Anatomy and Cell Biology, Temple University, Lewis Katz School of Medicine, Philadelphia, Pennsylvania, 19140.,Shriners Hospitals Pediatric Research Center, Temple University, Lewis Katz School of Medicine, Philadelphia, Pennsylvania, 19140
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21
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Compartmentalized Regulation of Parkin-Mediated Mitochondrial Quality Control in the Drosophila Nervous System In Vivo. J Neurosci 2017; 36:7375-91. [PMID: 27413149 DOI: 10.1523/jneurosci.0633-16.2016] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/18/2016] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED In neurons, the normal distribution and selective removal of mitochondria are considered essential for maintaining the functions of the large asymmetric cell and its diverse compartments. Parkin, a E3 ubiquitin ligase associated with familial Parkinson's disease, has been implicated in mitochondrial dynamics and removal in cells including neurons. However, it is not clear how Parkin functions in mitochondrial turnover in vivo, or whether Parkin-dependent events of the mitochondrial life cycle occur in all neuronal compartments. Here, using the live Drosophila nervous system, we investigated the involvement of Parkin in mitochondrial dynamics, distribution, morphology, and removal. Contrary to our expectations, we found that Parkin-deficient animals do not accumulate senescent mitochondria in their motor axons or neuromuscular junctions; instead, they contain far fewer axonal mitochondria, and these displayed normal motility behavior, morphology, and metabolic state. However, the loss of Parkin did produce abnormal tubular and reticular mitochondria restricted to the motor cell bodies. In addition, in contrast to drug-treated, immortalized cells in vitro, mature motor neurons rarely displayed Parkin-dependent mitophagy. These data indicate that the cell body is the focus of Parkin-dependent mitochondrial quality control in neurons, and argue that a selection process allows only healthy mitochondria to pass from cell bodies to axons, perhaps to limit the impact of mitochondrial dysfunction. SIGNIFICANCE STATEMENT Parkin has been proposed to police mitochondrial fidelity by binding to dysfunctional mitochondria via PTEN (phosphatase and tensin homolog)-induced putative kinase 1 (PINK1) and targeting them for autophagic degradation. However, it is unknown whether and how the PINK1/Parkin pathway regulates the mitochondrial life cycle in neurons in vivo Using Drosophila motor neurons, we show that parkin disruption generates an abnormal mitochondrial network in cell bodies in vivo and reduces the number of axonal mitochondria without producing any defects in their axonal transport, morphology, or metabolic state. Furthermore, while cultured neurons display Parkin-dependent axonal mitophagy, we find this is vanishingly rare in vivo under normal physiological conditions. Thus, both the spatial distribution and mechanism of mitochondrial quality control in vivo differ substantially from those observed in vitro.
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22
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Chaudhury AR, Insolera R, Hwang RD, Fridell YW, Collins C, Chronis N. On chip cryo-anesthesia of Drosophila larvae for high resolution in vivo imaging applications. LAB ON A CHIP 2017; 17:2303-2322. [PMID: 28613308 PMCID: PMC5559736 DOI: 10.1039/c7lc00345e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We present a microfluidic chip for immobilizing Drosophila melanogaster larvae for high resolution in vivo imaging. The chip creates a low-temperature micro-environment that anaesthetizes and immobilizes the larva in under 3 minutes. We characterized the temperature distribution within the chip and analyzed the resulting larval body movement using high resolution fluorescence imaging. Our results indicate that the proposed method minimizes submicron movements of internal organs and tissue without affecting the larva physiology. It can be used to continuously immobilize larvae for short periods of time (minutes) or for longer periods (several hours) if used intermittently. The same chip can be used to accommodate and immobilize arvae across all developmental stages (1st instar to late 3rd instar), and loading larvae onto the chip does not require any specialized skills. To demonstrate the usability of the chip, we observed mitochondrial trafficking in neurons from the cell bodies to the axon terminals along with mitochondrial fusion and neuro-synaptic growth through time in intact larvae. Besides studying sub-cellular processes and cellular development, we envision the use of on chip cryo-anesthesia in a wide variety of biological in vivo imaging applications, including observing organ development of the salivary glands, fat bodies and body-wall muscles.
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Affiliation(s)
- Amrita Ray Chaudhury
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
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23
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Liao PC, Tandarich LC, Hollenbeck PJ. ROS regulation of axonal mitochondrial transport is mediated by Ca2+ and JNK in Drosophila. PLoS One 2017; 12:e0178105. [PMID: 28542430 PMCID: PMC5436889 DOI: 10.1371/journal.pone.0178105] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 05/06/2017] [Indexed: 12/31/2022] Open
Abstract
Mitochondria perform critical functions including aerobic ATP production and calcium (Ca2+) homeostasis, but are also a major source of reactive oxygen species (ROS) production. To maintain cellular function and survival in neurons, mitochondria are transported along axons, and accumulate in regions with high demand for their functions. Oxidative stress and abnormal mitochondrial axonal transport are associated with neurodegenerative disorders. However, we know little about the connection between these two. Using the Drosophila third instar larval nervous system as the in vivo model, we found that ROS inhibited mitochondrial axonal transport more specifically, primarily due to reduced flux and velocity, but did not affect transport of other organelles. To understand the mechanisms underlying these effects, we examined Ca2+ levels and the JNK (c-Jun N-terminal Kinase) pathway, which have been shown to regulate mitochondrial transport and general fast axonal transport, respectively. We found that elevated ROS increased Ca2+ levels, and that experimental reduction of Ca2+ to physiological levels rescued ROS-induced defects in mitochondrial transport in primary neuron cell cultures. In addition, in vivo activation of the JNK pathway reduced mitochondrial flux and velocities, while JNK knockdown partially rescued ROS-induced defects in the anterograde direction. We conclude that ROS have the capacity to regulate mitochondrial traffic, and that Ca2+ and JNK signaling play roles in mediating these effects. In addition to transport defects, ROS produces imbalances in mitochondrial fission-fusion and metabolic state, indicating that mitochondrial transport, fission-fusion steady state, and metabolic state are closely interrelated in the response to ROS.
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Affiliation(s)
- Pin-Chao Liao
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Lauren C. Tandarich
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
| | - Peter J. Hollenbeck
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana, United States of America
- * E-mail:
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24
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Ba Q, Yang G. Intracellular organelle networks: Understanding their organization and communication through systems-level modeling and analysis. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/s11515-016-1436-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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25
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Yu J, Wang Y, Li Z, Dong S, Wang D, Gong L, Shi J, Zhang Y, Liu D, Mu R. Effect of Heme Oxygenase-1 on Mitofusin-1 protein in LPS-induced ALI/ARDS in rats. Sci Rep 2016; 6:36530. [PMID: 27830717 PMCID: PMC5103207 DOI: 10.1038/srep36530] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 10/18/2016] [Indexed: 01/11/2023] Open
Abstract
Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a common and important oxidative stress in the lung. Mitochondrial fusion responds to the normal morphology and function of cells and is finely regulated by mitochondrial fusion proteins, such as mitofusin-1 protein (Mfn1), mitofusin-2 protein (Mfn2) and optical atrophy 1 (OPA1). Additionally, Mfn1 has been identified as the most important protein in mitochondrial fusion. Heme oxygenase-1 (HO-1) is a stress-inducible protein that plays a critical role in protecting against oxidative stress. However, whether the protection of HO-1 is related to mitochondrial fusion is still a question. Thus, our in vitro and in vivo experiments aimed to identify the relationship between HO-1 and Mfn1. Here, we used Hemin and ZnPP-IX as treatments in an in vivo experiment. Then, HO-1 and Mfn1 were measured using RT-PCR and Western blotting. Supernatants were analyzed for MDA, SOD, and ROS. Our results implied that HO-1 upregulation suppressed oxidative stress induced by LPS, and the possible mechanism could be associated with Mfn1 and the PI3K/Akt pathway.
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Affiliation(s)
- Jianbo Yu
- Department of Anesthesiology, Tianjin Nan Kai Hospital, Tianjin Medical University, Tianjin, 300100, China
| | - Ying Wang
- Department of Anesthesiology, Tianjin Nan Kai Hospital, Tianjin Medical University, Tianjin, 300100, China
| | - Zhen Li
- Department of Anesthesiology, Tianjin Nan Kai Hospital, Tianjin Medical University, Tianjin, 300100, China
| | - Shuan Dong
- Department of Anesthesiology, Tianjin Nan Kai Hospital, Tianjin Medical University, Tianjin, 300100, China
| | - Dan Wang
- Department of Anesthesiology, Tianjin Nan Kai Hospital, Tianjin Medical University, Tianjin, 300100, China
| | - Lirong Gong
- Department of Anesthesiology, Tianjin Nan Kai Hospital, Tianjin Medical University, Tianjin, 300100, China
| | - Jia Shi
- Department of Anesthesiology, Tianjin Nan Kai Hospital, Tianjin Medical University, Tianjin, 300100, China
| | - Yuan Zhang
- Department of Anesthesiology, Tianjin Nan Kai Hospital, Tianjin Medical University, Tianjin, 300100, China
| | - Daquan Liu
- Institute of Acute Abdominal Diseases of Integrated Traditional Chinese and Western Medicine, Tianjin, 300100, China
| | - Rui Mu
- Department of Anesthesiology, Tianjin Nan Kai Hospital, Tianjin Medical University, Tianjin, 300100, China
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Hu H, Tan CC, Tan L, Yu JT. A Mitocentric View of Alzheimer's Disease. Mol Neurobiol 2016; 54:6046-6060. [PMID: 27696116 DOI: 10.1007/s12035-016-0117-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 09/12/2016] [Indexed: 12/14/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disease with an increasing morbidity, mortality, and economic cost. Plaques formed by amyloid beta peptide (Aβ) and neurofibrillary tangles formed by microtubule-associated protein tau are two main characters of AD. Though previous studies have focused on Aβ and tau and got some progressions on their toxicity mechanisms, no significantly effective treatments targeting the Aβ and tau have been found. However, it is worth noting that mounting evidences showed that mitochondrial dysfunction is an early event during the process of AD pathologic changes. What is more, these studies also showed an obvious association between mitochondrial dysfunction and Aβ/tau toxicity. Furthermore, both genetic and environmental factors may increase the oxidative stress and the mitochondria are also the sensitive target of ROS, which may form a vicious feedback between mitochondrial dysfunction and oxidative stress, eventually resulting in deficient energy, synaptic failure, and cell death. This article reviews the previous related studies from different aspects and concludes the critical roles of mitochondrial dysfunction in AD, suggesting a different route to AD therapy, which may guide the research and treatment direction.
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Affiliation(s)
- Hao Hu
- Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China
| | - Chen-Chen Tan
- Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China
| | - Lan Tan
- Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China.
| | - Jin-Tai Yu
- Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao, China.
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