1
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Masin L, Bergmans S, Van Dyck A, Farrow K, De Groef L, Moons L. Local glycolysis supports injury-induced axonal regeneration. J Cell Biol 2024; 223:e202402133. [PMID: 39352499 PMCID: PMC11451009 DOI: 10.1083/jcb.202402133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/09/2024] [Accepted: 09/09/2024] [Indexed: 10/06/2024] Open
Abstract
Successful axonal regeneration following injury requires the effective allocation of energy. How axons withstand the initial disruption in mitochondrial energy production caused by the injury and subsequently initiate regrowth is poorly understood. Transcriptomic data showed increased expression of glycolytic genes after optic nerve crush in retinal ganglion cells with the co-deletion of Pten and Socs3. Using retinal cultures in a multicompartment microfluidic device, we observed increased regrowth and enhanced mitochondrial trafficking in the axons of Pten and Socs3 co-deleted neurons. While wild-type axons relied on mitochondrial metabolism, after injury, in the absence of Pten and Socs3, energy production was supported by local glycolysis. Specific inhibition of lactate production hindered injury survival and the initiation of regrowth while slowing down glycolysis upstream impaired regrowth initiation, axonal elongation, and energy production. Together, these observations reveal that glycolytic ATP, combined with sustained mitochondrial transport, is essential for injury-induced axonal regrowth, providing new insights into the metabolic underpinnings of axonal regeneration.
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Affiliation(s)
- Luca Masin
- Department of Biology, Animal Physiology and Neurobiology Section, KU Leuven, Leuven Brain Institute, Leuven, Belgium
| | - Steven Bergmans
- Department of Biology, Animal Physiology and Neurobiology Section, KU Leuven, Leuven Brain Institute, Leuven, Belgium
| | - Annelies Van Dyck
- Department of Biology, Animal Physiology and Neurobiology Section, KU Leuven, Leuven Brain Institute, Leuven, Belgium
| | - Karl Farrow
- Department of Biology, Animal Physiology and Neurobiology Section, KU Leuven, Leuven Brain Institute, Leuven, Belgium
- Neuro-Electronics Research Flanders, Vlaams Instituut voor Biotechnologie, Leuven, Belgium
- imec, Leuven, Belgium
| | - Lies De Groef
- Department of Biology, Animal Physiology and Neurobiology Section, KU Leuven, Leuven Brain Institute, Leuven, Belgium
| | - Lieve Moons
- Department of Biology, Animal Physiology and Neurobiology Section, KU Leuven, Leuven Brain Institute, Leuven, Belgium
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2
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Kuznetsov AV. Effects of Time-Dependent Adenosine Triphosphate Consumption Caused by Neuron Firing on Adenosine Triphosphate Concentrations in Synaptic Boutons Containing and Lacking a Stationary Mitochondrion. J Biomech Eng 2024; 146:111002. [PMID: 38888293 DOI: 10.1115/1.4065743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 06/10/2024] [Indexed: 06/20/2024]
Abstract
The precise mechanism behind the supply of adenosine triphosphate (ATP) to approximately half of the presynaptic release sites in axons that lack a stationary mitochondrion is not fully understood. This paper presents a mathematical model designed to simulate the transient ATP concentration in presynaptic en passant boutons. The model is utilized to investigate how the ATP concentration responds to increased ATP demand during neuronal firing in boutons with a stationary mitochondrion and those without one. The analysis suggests that neuron firing may cause oscillations in the ATP concentrations, with peak-to-peak amplitudes ranging from 0.06% to 5% of their average values. However, this does not deplete boutons lacking a mitochondrion of ATP; for physiologically relevant values of model parameters, their concentration remains approximately 3.75 times higher than the minimum concentration required for synaptic activity. The variance in average ATP concentrations between boutons containing a stationary mitochondrion and those lacking one ranges from 0.3% to 0.8%, contingent on the distance between the boutons. The model indicates that diffusion-driven ATP transport is rapid enough to adequately supply ATP molecules to boutons lacking a stationary mitochondrion.
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Affiliation(s)
- Andrey V Kuznetsov
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910
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3
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Wu W, Zhang J, Chen Y, Chen Q, Liu Q, Zhang F, Li S, Wang X. Genes in Axonal Regeneration. Mol Neurobiol 2024; 61:7431-7447. [PMID: 38388774 DOI: 10.1007/s12035-024-04049-z] [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: 09/13/2023] [Accepted: 02/06/2024] [Indexed: 02/24/2024]
Abstract
This review explores the molecular and genetic underpinnings of axonal regeneration and functional recovery post-nerve injury, emphasizing its significance in reversing neurological deficits. It presents a systematic exploration of the roles of various genes in axonal regrowth across peripheral and central nerve injuries. Initially, it highlights genes and gene families critical for axonal growth and guidance, delving into their roles in regeneration. It then examines the regenerative microenvironment, focusing on the role of glial cells in neural repair through dedifferentiation, proliferation, and migration. The concept of "traumatic microenvironments" within the central nervous system (CNS) and peripheral nervous system (PNS) is discussed, noting their impact on regenerative capacities and their importance in therapeutic strategy development. Additionally, the review delves into axonal transport mechanisms essential for accurate growth and reinnervation, integrating insights from proteomics, genome-wide screenings, and gene editing advancements. Conclusively, it synthesizes these insights to offer a comprehensive understanding of axonal regeneration's molecular orchestration, aiming to inform effective nerve injury therapies and contribute to regenerative neuroscience.
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Affiliation(s)
- Wenshuang Wu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Jing Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Yu Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China
| | - Qianqian Chen
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Qianyan Liu
- School of Acupuncture-Moxibustion, Tuina and Rehabilitation, Hunan University of Chinese Medicine, Changsha, 410208, China
| | - Fuchao Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Shiying Li
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China.
| | - Xinghui Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, 226001, China.
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4
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Guerra San Juan I, Brunner J, Eggan K, Toonen RF, Verhage M. KIF5A regulates axonal repair and time-dependent axonal transport of SFPQ granules and mitochondria in human motor neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.06.611684. [PMID: 39314491 PMCID: PMC11418931 DOI: 10.1101/2024.09.06.611684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/25/2024]
Abstract
Mutations in the microtubule binding motor protein, kinesin family member 5A (KIF5A), cause the fatal motor neuron disease, Amyotrophic Lateral Sclerosis. While KIF5 family members transport a variety of cargos along axons, it is still unclear which cargos are affected by KIF5A mutations. We generated KIF5A null mutant human motor neurons to investigate the impact of KIF5A loss on the transport of various cargoes and its effect on motor neuron function at two different timepoints in vitro. The absence of KIF5A resulted in reduced neurite complexity in young motor neurons (DIV14) and significant defects in axonal regeneration capacity at all developmental stages. KIF5A loss did not affect neurofilament transport but resulted in decreased mitochondria motility and anterograde speed at DIV42. More prominently, KIF5A depletion strongly reduced anterograde transport of SFPQ-associated RNA granules in DIV42 motor neuron axons. We conclude that KIF5A most prominently functions in human motor neurons to promote axonal regrowth after injury as well as to anterogradely transport mitochondria and, to a larger extent, SFPQ-associated RNA granules in a time-dependent manner.
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Affiliation(s)
- Irune Guerra San Juan
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam and VU Medical Center, Amsterdam, The Netherlands
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA
- Department of Human Genetics, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Jessie Brunner
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam and VU Medical Center, Amsterdam, The Netherlands
- Department of Human Genetics, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Kevin Eggan
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Ruud F Toonen
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam and VU Medical Center, Amsterdam, The Netherlands
- Department of Human Genetics, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Matthijs Verhage
- Department of Functional Genomics, Center for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam and VU Medical Center, Amsterdam, The Netherlands
- Department of Human Genetics, Amsterdam University Medical Center, Amsterdam, The Netherlands
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5
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Khaliulin I, Hamoudi W, Amal H. The multifaceted role of mitochondria in autism spectrum disorder. Mol Psychiatry 2024:10.1038/s41380-024-02725-z. [PMID: 39223276 DOI: 10.1038/s41380-024-02725-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 08/21/2024] [Accepted: 08/23/2024] [Indexed: 09/04/2024]
Abstract
Normal brain functioning relies on high aerobic energy production provided by mitochondria. Failure to supply a sufficient amount of energy, seen in different brain disorders, including autism spectrum disorder (ASD), may have a significant negative impact on brain development and support of different brain functions. Mitochondrial dysfunction, manifested in the abnormal activities of the electron transport chain and impaired energy metabolism, greatly contributes to ASD. The aberrant functioning of this organelle is of such high importance that ASD has been proposed as a mitochondrial disease. It should be noted that aerobic energy production is not the only function of the mitochondria. In particular, these organelles are involved in the regulation of Ca2+ homeostasis, different mechanisms of programmed cell death, autophagy, and reactive oxygen and nitrogen species (ROS and RNS) production. Several syndromes originated from mitochondria-related mutations display ASD phenotype. Abnormalities in Ca2+ handling and ATP production in the brain mitochondria affect synaptic transmission, plasticity, and synaptic development, contributing to ASD. ROS and Ca2+ regulate the activity of the mitochondrial permeability transition pore (mPTP). The prolonged opening of this pore affects the redox state of the mitochondria, impairs oxidative phosphorylation, and activates apoptosis, ultimately leading to cell death. A dysregulation between the enhanced mitochondria-related processes of apoptosis and the inhibited autophagy leads to the accumulation of toxic products in the brains of individuals with ASD. Although many mitochondria-related mechanisms still have to be investigated, and whether they are the cause or consequence of this disorder is still unknown, the accumulating data show that the breakdown of any of the mitochondrial functions may contribute to abnormal brain development leading to ASD. In this review, we discuss the multifaceted role of mitochondria in ASD from the various aspects of neuroscience.
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Affiliation(s)
- Igor Khaliulin
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Wajeha Hamoudi
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Haitham Amal
- Institute for Drug Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
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6
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Bame X, Hill RA. Mitochondrial network reorganization and transient expansion during oligodendrocyte generation. Nat Commun 2024; 15:6979. [PMID: 39143079 PMCID: PMC11324877 DOI: 10.1038/s41467-024-51016-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 07/24/2024] [Indexed: 08/16/2024] Open
Abstract
Oligodendrocyte precursor cells (OPCs) give rise to myelinating oligodendrocytes of the brain. This process persists throughout life and is essential for recovery from neurodegeneration. To better understand the cellular checkpoints that occur during oligodendrogenesis, we determined the mitochondrial distribution and morphometrics across the oligodendrocyte lineage in mouse and human cerebral cortex. During oligodendrocyte generation, mitochondrial content expands concurrently with a change in subcellular partitioning towards the distal processes. These changes are followed by an abrupt loss of mitochondria in the oligodendrocyte processes and myelin, coinciding with sheath compaction. This reorganization and extensive expansion and depletion take 3 days. Oligodendrocyte mitochondria are stationary over days while OPC mitochondrial motility is modulated by animal arousal state within minutes. Aged OPCs also display decreased mitochondrial size, volume fraction, and motility. Thus, mitochondrial dynamics are linked to oligodendrocyte generation, dynamically modified by their local microenvironment, and altered in the aging brain.
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Affiliation(s)
- Xhoela Bame
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Robert A Hill
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA.
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7
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Jenkins JE, Fazli M, Evans CS. Mitochondrial motility modulators coordinate quality control dynamics to promote neuronal health. Curr Opin Cell Biol 2024; 89:102383. [PMID: 38908094 DOI: 10.1016/j.ceb.2024.102383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 05/24/2024] [Accepted: 05/28/2024] [Indexed: 06/24/2024]
Abstract
Dysfunction in mitochondrial maintenance and trafficking is commonly correlated with the development of neurodegenerative disorders such as Parkinson's disease and Alzheimer's disease. Thus, biomedical research has been dedicated to understanding how architecturally complex neurons maintain and transport their mitochondria. However, the systems that coordinate mitochondrial QC (quality control) dynamics and trafficking in response to neuronal activity and stress are less understood. Additionally, the degree of integration between the processes of mitochondrial trafficking and QC is unclear. Recent work indicates that mitochondrial motility modulators (i.e., anchors and tethers) help coordinate mitochondrial health by mediating distinct, stress-level-appropriate QC pathways following mitochondrial damage. This review summarizes current evidence supporting the role of two mitochondrial motility modulators, Syntaphilin and Mitofusin 2, in coordinating mitochondrial QC to promote neuronal health. Exploring motility modulators' intricate regulatory molecular landscape may reveal new therapeutic targets for delaying disease progression and enhancing neuronal survival post-insult.
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Affiliation(s)
- Jennifer E Jenkins
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Mohammad Fazli
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Chantell S Evans
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA; Howard Hughes Medical Institute, Duke University School of Medicine, Durham, NC 27710, USA.
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8
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Sayehmiri F, Motamedi F, Batool Z, Naderi N, Shaerzadeh F, Zoghi A, Rezaei O, Khodagholi F, Pourbadie HG. Mitochondrial plasticity and synaptic plasticity crosstalk; in health and Alzheimer's disease. CNS Neurosci Ther 2024; 30:e14897. [PMID: 39097920 PMCID: PMC11298206 DOI: 10.1111/cns.14897] [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: 01/05/2024] [Revised: 06/19/2024] [Accepted: 07/18/2024] [Indexed: 08/06/2024] Open
Abstract
Synaptic plasticity is believed to underlie the cellular and molecular basis of memory formation. Mitochondria are one of the main organelles involved in metabolism and energy maintenance as plastic organelles that change morphologically and functionally in response to cellular needs and regulate synaptic function and plasticity through multiple mechanisms, including ATP generation, calcium homeostasis, and biogenesis. An increased neuronal activity enhances synaptic efficiency, during which mitochondria's spatial distribution and morphology change significantly. These organelles build up in the pre-and postsynaptic zones to produce ATP, which is necessary for several synaptic processes like neurotransmitter release and recycling. Mitochondria also regulate calcium homeostasis by buffering intracellular calcium, which ensures proper synaptic activity. Furthermore, mitochondria in the presynaptic terminal have distinct morphological properties compared to dendritic or postsynaptic mitochondria. This specialization enables precise control of synaptic activity and plasticity. Mitochondrial dysfunction has been linked to synaptic failure in many neurodegenerative disorders, like Alzheimer's disease (AD). In AD, malfunctioning mitochondria cause delays in synaptic vesicle release and recycling, ionic gradient imbalances, and mostly synaptic failure. This review emphasizes mitochondrial plasticity's contribution to synaptic function. It also explores the profound effect of mitochondrial malfunction on neurodegenerative disorders, focusing on AD, and provides an overview of how they sustain cellular health under normal conditions and how their malfunction contributes to neurodegenerative diseases, highlighting their potential as a therapeutic target for such conditions.
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Affiliation(s)
- Fatemeh Sayehmiri
- Neuroscience Research Center, Faculty of MedicineShahid Beheshti University of Medical SciencesTehranIran
| | - Fereshteh Motamedi
- Neuroscience Research Center, Faculty of MedicineShahid Beheshti University of Medical SciencesTehranIran
- Faculty of MedicineShahid Beheshti University of Medical SciencesTehranIran
| | - Zehra Batool
- Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological SciencesUniversity of KarachiKarachiPakistan
| | - Nima Naderi
- Department of Pharmacology and Toxicology, Faculty of PharmacyShahid Beheshti University of Medical SciencesTehranIran
| | | | - Anahita Zoghi
- Department of Neurology, Loghman Hakim HospitalShahid Beheshti University of Medical SciencesTehranIran
| | - Omidvar Rezaei
- Skull Base Research CenterLoghman Hakim Hospital, Shahid Beheshti University of Medical SciencesTehranIran
| | - Fariba Khodagholi
- Neuroscience Research Center, Faculty of MedicineShahid Beheshti University of Medical SciencesTehranIran
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9
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Kuznetsov IA, Kuznetsov AV. Mitochondrial transport in symmetric and asymmetric axons with multiple branching junctions: a computational study. Comput Methods Biomech Biomed Engin 2024; 27:1071-1090. [PMID: 37424316 PMCID: PMC10776827 DOI: 10.1080/10255842.2023.2226787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/10/2023] [Accepted: 06/10/2023] [Indexed: 07/11/2023]
Abstract
Mitochondrial aging has been proposed to be involved in a variety of neurodegenerative disorders, such as Parkinson's disease. Here, we explore the impact of multiple branching junctions in axons on the mean age of mitochondria and their age density distributions in demand sites. The study examined mitochondrial concentration, mean age, and age density distribution in relation to the distance from the soma. We developed models for a symmetric axon containing 14 demand sites and an asymmetric axon containing 10 demand sites. We investigated how the concentration of mitochondria changes when an axon splits into two branches at the branching junction. Additionally, we studied whether mitochondrial concentrations in the branches are affected by what proportion of mitochondrial flux enters the upper branch versus the lower branch. Furthermore, we explored whether the distributions of mitochondrial mean age and age density in branching axons are affected by how the mitochondrial flux splits at the branching junction. When the mitochondrial flux is unevenly split at the branching junction of an asymmetric axon, with a greater proportion of the flux entering the longer branch, the average age of mitochondria (system age) in the axon increases. Our findings elucidate the effects of axonal branching on the mitochondrial age.
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Affiliation(s)
- Ivan A Kuznetsov
- Perelman School of Medicine, University of PA, Philadelphia, PA, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Andrey V Kuznetsov
- Department of Mechanical and Aerospace Engineering, NC State University, Raleigh, NC, USA
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10
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Myeong J, Stunault MI, Klyachko VA, Ashrafi G. Metabolic regulation of single synaptic vesicle exo- and endocytosis in hippocampal synapses. Cell Rep 2024; 43:114218. [PMID: 38758651 PMCID: PMC11221188 DOI: 10.1016/j.celrep.2024.114218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 02/26/2024] [Accepted: 04/25/2024] [Indexed: 05/19/2024] Open
Abstract
Glucose has long been considered a primary energy source for synaptic function. However, it remains unclear to what extent alternative fuels, such as lactate/pyruvate, contribute to powering synaptic transmission. By detecting individual release events in hippocampal synapses, we find that mitochondrial ATP production regulates basal vesicle release probability and release location within the active zone (AZ), evoked by single action potentials. Mitochondrial inhibition shifts vesicle release closer to the AZ center and alters the efficiency of vesicle retrieval by increasing the occurrence of ultrafast endocytosis. Furthermore, we uncover that terminals can use oxidative fuels to maintain the vesicle cycle during trains of activity. Mitochondria are sparsely distributed along hippocampal axons, and we find that terminals containing mitochondria display enhanced vesicle release and reuptake during high-frequency trains. Our findings suggest that mitochondria not only regulate several fundamental features of synaptic transmission but may also contribute to modulation of short-term synaptic plasticity.
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Affiliation(s)
- Jongyun Myeong
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Marion I Stunault
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Vitaly A Klyachko
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Ghazaleh Ashrafi
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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11
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Donovan EJ, Agrawal A, Liberman N, Kalai JI, Adler AJ, Lamper AM, Wang HQ, Chua NJ, Koslover EF, Barnhart EL. Dendrite architecture determines mitochondrial distribution patterns in vivo. Cell Rep 2024; 43:114190. [PMID: 38717903 DOI: 10.1016/j.celrep.2024.114190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 01/08/2024] [Accepted: 04/17/2024] [Indexed: 06/01/2024] Open
Abstract
Neuronal morphology influences synaptic connectivity and neuronal signal processing. However, it remains unclear how neuronal shape affects steady-state distributions of organelles like mitochondria. In this work, we investigated the link between mitochondrial transport and dendrite branching patterns by combining mathematical modeling with in vivo measurements of dendrite architecture, mitochondrial motility, and mitochondrial localization patterns in Drosophila HS (horizontal system) neurons. In our model, different forms of morphological and transport scaling rules-which set the relative thicknesses of parent and daughter branches at each junction in the dendritic arbor and link mitochondrial motility to branch thickness-predict dramatically different global mitochondrial localization patterns. We show that HS dendrites obey the specific subset of scaling rules that, in our model, lead to realistic mitochondrial distributions. Moreover, we demonstrate that neuronal activity does not affect mitochondrial transport or localization, indicating that steady-state mitochondrial distributions are hard-wired by the architecture of the neuron.
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Affiliation(s)
- Eavan J Donovan
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Anamika Agrawal
- Department of Physics, University of California, San Diego, La Jolla, CA 92092, USA
| | - Nicole Liberman
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Jordan I Kalai
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Avi J Adler
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Adam M Lamper
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Hailey Q Wang
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Nicholas J Chua
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA
| | - Elena F Koslover
- Department of Physics, University of California, San Diego, La Jolla, CA 92092, USA
| | - Erin L Barnhart
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
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12
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Wu Y, Ding C, Sharif B, Weinreb A, Swaim G, Hao H, Yogev S, Watanabe S, Hammarlund M. Polarized localization of kinesin-1 and RIC-7 drives axonal mitochondria anterograde transport. J Cell Biol 2024; 223:e202305105. [PMID: 38470363 PMCID: PMC10932739 DOI: 10.1083/jcb.202305105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 12/17/2023] [Accepted: 02/26/2024] [Indexed: 03/13/2024] Open
Abstract
Mitochondria transport is crucial for axonal mitochondria distribution and is mediated by kinesin-1-based anterograde and dynein-based retrograde motor complexes. While Miro and Milton/TRAK were identified as key adaptors between mitochondria and kinesin-1, recent studies suggest the presence of additional mechanisms. In C. elegans, ric-7 is the only single gene described so far, other than kinesin-1, that is absolutely required for axonal mitochondria localization. Using CRISPR engineering in C. elegans, we find that Miro is important but is not essential for anterograde traffic, whereas it is required for retrograde traffic. Both the endogenous RIC-7 and kinesin-1 act at the leading end to transport mitochondria anterogradely. RIC-7 binding to mitochondria requires its N-terminal domain and partially relies on MIRO-1, whereas RIC-7 accumulation at the leading end depends on its disordered region, kinesin-1, and metaxin2. We conclude that transport complexes containing kinesin-1 and RIC-7 polarize at the leading edge of mitochondria and are required for anterograde axonal transport in C. elegans.
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Affiliation(s)
- Youjun Wu
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Chen Ding
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Behrang Sharif
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Alexis Weinreb
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Grace Swaim
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Hongyan Hao
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Shaul Yogev
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
| | - Shigeki Watanabe
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marc Hammarlund
- Department of Genetics, Yale University School of Medicine, New Haven, CT, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA
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13
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Valderhaug VD, Ramstad OH, van de Wijdeven R, Heiney K, Nichele S, Sandvig A, Sandvig I. Micro-and mesoscale aspects of neurodegeneration in engineered human neural networks carrying the LRRK2 G2019S mutation. Front Cell Neurosci 2024; 18:1366098. [PMID: 38644975 PMCID: PMC11026646 DOI: 10.3389/fncel.2024.1366098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 03/11/2024] [Indexed: 04/23/2024] Open
Abstract
Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene have been widely linked to Parkinson's disease, where the G2019S variant has been shown to contribute uniquely to both familial and sporadic forms of the disease. LRRK2-related mutations have been extensively studied, yet the wide variety of cellular and network events related to these mutations remain poorly understood. The advancement and availability of tools for neural engineering now enable modeling of selected pathological aspects of neurodegenerative disease in human neural networks in vitro. Our study revealed distinct pathology associated dynamics in engineered human cortical neural networks carrying the LRRK2 G2019S mutation compared to healthy isogenic control neural networks. The neurons carrying the LRRK2 G2019S mutation self-organized into networks with aberrant morphology and mitochondrial dynamics, affecting emerging structure-function relationships both at the micro-and mesoscale. Taken together, the findings of our study points toward an overall heightened metabolic demand in networks carrying the LRRK2 G2019S mutation, as well as a resilience to change in response to perturbation, compared to healthy isogenic controls.
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Affiliation(s)
- Vibeke Devold Valderhaug
- Department of Research and Innovation, Møre and Romsdal Hospital Trust, Ålesund, Norway
- Department of Neuromedicine and Movement Science, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Ola Huse Ramstad
- Department of Neuromedicine and Movement Science, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Rosanne van de Wijdeven
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, NTNU, Trondheim, Norway
| | - Kristine Heiney
- Department of Computer Science, Faculty of Technology, Art and Design, Oslo Metropolitan University (OsloMet), Oslo, Norway
- Department of Computer Science, Faculty of Information Technology and Electrical Engineering, NTNU, Trondheim, Norway
| | - Stefano Nichele
- Department of Computer Science, Faculty of Technology, Art and Design, Oslo Metropolitan University (OsloMet), Oslo, Norway
- Department of Computer Science and Communication, Østfold University College, Halden, Norway
| | - Axel Sandvig
- Department of Neuromedicine and Movement Science, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Department of Clinical Neuroscience, Division of Neuro, Head and Neck, Umeå University Hospital, Umeå, Sweden
- Department of Community Medicine and Rehabilitation, Umeå University, Umeå, Sweden
- Department of Neurology and Clinical Neurophysiology, St Olav’s Hospital, Trondheim, Norway
| | - Ioanna Sandvig
- Department of Neuromedicine and Movement Science, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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14
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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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15
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Virga DM, Hamilton S, Osei B, Morgan A, Kneis P, Zamponi E, Park NJ, Hewitt VL, Zhang D, Gonzalez KC, Russell FM, Grahame Hardie D, Prudent J, Bloss E, Losonczy A, Polleux F, Lewis TL. Activity-dependent compartmentalization of dendritic mitochondria morphology through local regulation of fusion-fission balance in neurons in vivo. Nat Commun 2024; 15:2142. [PMID: 38459070 PMCID: PMC10923867 DOI: 10.1038/s41467-024-46463-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 02/27/2024] [Indexed: 03/10/2024] Open
Abstract
Neuronal mitochondria play important roles beyond ATP generation, including Ca2+ uptake, and therefore have instructive roles in synaptic function and neuronal response properties. Mitochondrial morphology differs significantly between the axon and dendrites of a given neuronal subtype, but in CA1 pyramidal neurons (PNs) of the hippocampus, mitochondria within the dendritic arbor also display a remarkable degree of subcellular, layer-specific compartmentalization. In the dendrites of these neurons, mitochondria morphology ranges from highly fused and elongated in the apical tuft, to more fragmented in the apical oblique and basal dendritic compartments, and thus occupy a smaller fraction of dendritic volume than in the apical tuft. However, the molecular mechanisms underlying this striking degree of subcellular compartmentalization of mitochondria morphology are unknown, precluding the assessment of its impact on neuronal function. Here, we demonstrate that this compartment-specific morphology of dendritic mitochondria requires activity-dependent, Ca2+ and Camkk2-dependent activation of AMPK and its ability to phosphorylate two direct effectors: the pro-fission Drp1 receptor Mff and the recently identified anti-fusion, Opa1-inhibiting protein, Mtfr1l. Our study uncovers a signaling pathway underlying the subcellular compartmentalization of mitochondrial morphology in dendrites of neurons in vivo through spatially precise and activity-dependent regulation of mitochondria fission/fusion balance.
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Affiliation(s)
- Daniel M Virga
- Department of Neuroscience, Columbia University, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Stevie Hamilton
- Department of Neuroscience, Columbia University, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Bertha Osei
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Abigail Morgan
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Neuroscience, Biochemistry & Molecular Biology, Oklahoma University Health Science Campus, Oklahoma City, OK, USA
| | - Parker Kneis
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Neuroscience, Biochemistry & Molecular Biology, Oklahoma University Health Science Campus, Oklahoma City, OK, USA
| | - Emiliano Zamponi
- Department of Neuroscience, Columbia University, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Natalie J Park
- Department of Neuroscience, Columbia University, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Victoria L Hewitt
- Department of Neuroscience, Columbia University, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - David Zhang
- Department of Neuroscience, Columbia University, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Kevin C Gonzalez
- Department of Neuroscience, Columbia University, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Fiona M Russell
- Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK
| | - D Grahame Hardie
- Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK
| | - Julien Prudent
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, CB2 0XY, Cambridge, UK
| | - Erik Bloss
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME, 04609, USA
| | - Attila Losonczy
- Department of Neuroscience, Columbia University, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA
| | - Franck Polleux
- Department of Neuroscience, Columbia University, New York, NY, USA.
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY, USA.
| | - Tommy L Lewis
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA.
- Neuroscience, Biochemistry & Molecular Biology, Oklahoma University Health Science Campus, Oklahoma City, OK, USA.
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16
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Hirabayashi Y, Lewis TL, Du Y, Virga DM, Decker AM, Coceano G, Alvelid J, Paul MA, Hamilton S, Kneis P, Takahashi Y, Gaublomme JT, Testa I, Polleux F. Most axonal mitochondria in cortical pyramidal neurons lack mitochondrial DNA and consume ATP. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.12.579972. [PMID: 38405915 PMCID: PMC10888904 DOI: 10.1101/2024.02.12.579972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
In neurons of the mammalian central nervous system (CNS), axonal mitochondria are thought to be indispensable for supplying ATP during energy-consuming processes such as neurotransmitter release. Here, we demonstrate using multiple, independent, in vitro and in vivo approaches that the majority (~80-90%) of axonal mitochondria in cortical pyramidal neurons (CPNs), lack mitochondrial DNA (mtDNA). Using dynamic, optical imaging analysis of genetically encoded sensors for mitochondrial matrix ATP and pH, we demonstrate that in axons of CPNs, but not in their dendrites, mitochondrial complex V (ATP synthase) functions in a reverse way, consuming ATP and protruding H+ out of the matrix to maintain mitochondrial membrane potential. Our results demonstrate that in mammalian CPNs, axonal mitochondria do not play a major role in ATP supply, despite playing other functions critical to regulating neurotransmission such as Ca2+ buffering.
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Affiliation(s)
- Yusuke Hirabayashi
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo; Tokyo, 113-8656, Japan
| | - Tommy L. Lewis
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Yudan Du
- Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo; Tokyo, 113-8656, Japan
| | - Daniel M. Virga
- Department of Biological Sciences, Columbia University; New York, NY, 10027, USA
- Department of Neuroscience, Columbia University; New York, NY, 10027, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, USA
| | - Aubrianna M. Decker
- Department of Biological Sciences, Columbia University; New York, NY, 10027, USA
| | - Giovanna Coceano
- Department of Applied Physics and SciLifeLab, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Jonatan Alvelid
- Department of Applied Physics and SciLifeLab, KTH Royal Institute of Technology, Stockholm, Sweden
- Department of Biophysical Imaging, Leibniz Institute of Photonic Technology, Jena, Germany
| | - Maëla A. Paul
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, USA
- Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS, INSERM, Université PSL; Paris, France
| | - Stevie Hamilton
- Department of Neuroscience, Columbia University; New York, NY, 10027, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, USA
| | - Parker Kneis
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Yasufumi Takahashi
- Department of Electronics, Graduate School of Engineering, Nagoya University, 464-8603, Nagoya, Japan
- Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, 920–1192 Japan
| | - Jellert T. Gaublomme
- Department of Biological Sciences, Columbia University; New York, NY, 10027, USA
| | - Ilaria Testa
- Department of Applied Physics and SciLifeLab, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Franck Polleux
- Department of Neuroscience, Columbia University; New York, NY, 10027, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University; New York, NY, 10027, USA
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17
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Yang S, Niou ZX, Enriquez A, LaMar J, Huang JY, Ling K, Jafar-Nejad P, Gilley J, Coleman MP, Tennessen JM, Rangaraju V, Lu HC. NMNAT2 supports vesicular glycolysis via NAD homeostasis to fuel fast axonal transport. Mol Neurodegener 2024; 19:13. [PMID: 38282024 PMCID: PMC10823734 DOI: 10.1186/s13024-023-00690-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 11/28/2023] [Indexed: 01/30/2024] Open
Abstract
BACKGROUND Bioenergetic maladaptations and axonopathy are often found in the early stages of neurodegeneration. Nicotinamide adenine dinucleotide (NAD), an essential cofactor for energy metabolism, is mainly synthesized by Nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2) in CNS neurons. NMNAT2 mRNA levels are reduced in the brains of Alzheimer's, Parkinson's, and Huntington's disease. Here we addressed whether NMNAT2 is required for axonal health of cortical glutamatergic neurons, whose long-projecting axons are often vulnerable in neurodegenerative conditions. We also tested if NMNAT2 maintains axonal health by ensuring axonal ATP levels for axonal transport, critical for axonal function. METHODS We generated mouse and cultured neuron models to determine the impact of NMNAT2 loss from cortical glutamatergic neurons on axonal transport, energetic metabolism, and morphological integrity. In addition, we determined if exogenous NAD supplementation or inhibiting a NAD hydrolase, sterile alpha and TIR motif-containing protein 1 (SARM1), prevented axonal deficits caused by NMNAT2 loss. This study used a combination of techniques, including genetics, molecular biology, immunohistochemistry, biochemistry, fluorescent time-lapse imaging, live imaging with optical sensors, and anti-sense oligos. RESULTS We provide in vivo evidence that NMNAT2 in glutamatergic neurons is required for axonal survival. Using in vivo and in vitro studies, we demonstrate that NMNAT2 maintains the NAD-redox potential to provide "on-board" ATP via glycolysis to vesicular cargos in distal axons. Exogenous NAD+ supplementation to NMNAT2 KO neurons restores glycolysis and resumes fast axonal transport. Finally, we demonstrate both in vitro and in vivo that reducing the activity of SARM1, an NAD degradation enzyme, can reduce axonal transport deficits and suppress axon degeneration in NMNAT2 KO neurons. CONCLUSION NMNAT2 ensures axonal health by maintaining NAD redox potential in distal axons to ensure efficient vesicular glycolysis required for fast axonal transport.
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Affiliation(s)
- Sen Yang
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Zhen-Xian Niou
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Andrea Enriquez
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Jacob LaMar
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- Present address: Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Jui-Yen Huang
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Karen Ling
- Neuroscience Drug Discovery, Ionis Pharmaceuticals, Inc., 2855, Gazelle Court, Carlsbad, CA, 92010, USA
| | - Paymaan Jafar-Nejad
- Neuroscience Drug Discovery, Ionis Pharmaceuticals, Inc., 2855, Gazelle Court, Carlsbad, CA, 92010, USA
| | - Jonathan Gilley
- Department of Clinical Neuroscience, Cambridge University, Cambridge, UK
| | - Michael P Coleman
- Department of Clinical Neuroscience, Cambridge University, Cambridge, UK
| | - Jason M Tennessen
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Vidhya Rangaraju
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Hui-Chen Lu
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA.
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18
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Bapat O, Purimetla T, Kruessel S, Shah M, Fan R, Thum C, Rupprecht F, Langer JD, Rangaraju V. VAP spatially stabilizes dendritic mitochondria to locally support synaptic plasticity. Nat Commun 2024; 15:205. [PMID: 38177103 PMCID: PMC10766606 DOI: 10.1038/s41467-023-44233-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 12/05/2023] [Indexed: 01/06/2024] Open
Abstract
Synapses are pivotal sites of plasticity and memory formation. Consequently, synapses are energy consumption hotspots susceptible to dysfunction when their energy supplies are perturbed. Mitochondria are stabilized near synapses via the cytoskeleton and provide the local energy required for synaptic plasticity. However, the mechanisms that tether and stabilize mitochondria to support synaptic plasticity are unknown. We identified proteins exclusively tethering mitochondria to actin near postsynaptic spines. We find that VAP, the vesicle-associated membrane protein-associated protein implicated in amyotrophic lateral sclerosis, stabilizes mitochondria via actin near the spines. To test if the VAP-dependent stable mitochondrial compartments can locally support synaptic plasticity, we used two-photon glutamate uncaging for spine plasticity induction and investigated the induced and adjacent uninduced spines. We find VAP functions as a spatial stabilizer of mitochondrial compartments for up to ~60 min and as a spatial ruler determining the ~30 μm dendritic segment supported during synaptic plasticity.
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Affiliation(s)
- Ojasee Bapat
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- International Max Planck Research School for Synapses and Circuits, Jupiter, FL, 33458, USA
| | - Tejas Purimetla
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- Geisel School of Medicine at Dartmouth, Hanover, NH, 03755-1404, USA
| | - Sarah Kruessel
- Max Planck Institute for Brain Research, Frankfurt, 60438, Germany
- Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Monil Shah
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- International Max Planck Research School for Synapses and Circuits, Jupiter, FL, 33458, USA
| | - Ruolin Fan
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Christina Thum
- Max Planck Institute for Brain Research, Frankfurt, 60438, Germany
| | - Fiona Rupprecht
- Max Planck Institute for Brain Research, Frankfurt, 60438, Germany
- Max Planck Institute of Biophysics, Frankfurt, 60438, Germany
- Thermo Fisher Diagnostics GmbH, Henningsdorf, 16761, Germany
| | - Julian D Langer
- Max Planck Institute for Brain Research, Frankfurt, 60438, Germany
- Max Planck Institute of Biophysics, Frankfurt, 60438, Germany
| | - Vidhya Rangaraju
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA.
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19
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Bame X, Hill RA. Mitochondrial network reorganization and transient expansion during oligodendrocyte generation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570104. [PMID: 38106204 PMCID: PMC10723275 DOI: 10.1101/2023.12.05.570104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Oligodendrocyte precursor cells (OPCs) give rise to myelinating oligodendrocytes of the central nervous system. This process persists throughout life and is essential for recovery from neurodegeneration. To better understand the cellular checkpoints that occur during oligodendrogenesis, we determined the mitochondrial distribution and morphometrics across the oligodendrocyte lineage in mouse and human cerebral cortex. During oligodendrocyte generation, mitochondrial content expanded concurrently with a change in subcellular partitioning towards the distal processes. These changes were followed by an abrupt loss of mitochondria in the oligodendrocyte processes and myelin, coinciding with sheath compaction. This reorganization and extensive expansion and depletion took 3 days. Oligodendrocyte mitochondria were stationary over days while OPC mitochondrial motility was modulated by animal arousal state within minutes. Aged OPCs also displayed decreased mitochondrial size, content, and motility. Thus, mitochondrial dynamics are linked to oligodendrocyte generation, dynamically modified by their local microenvironment, and altered in the aging brain.
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Affiliation(s)
- Xhoela Bame
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
| | - Robert A Hill
- Department of Biological Sciences, Dartmouth College, Hanover, NH, USA
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20
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Kuznetsov IA, Kuznetsov AV. Effect of mitochondrial circulation on mitochondrial age density distribution. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023; 39:e3770. [PMID: 37688421 PMCID: PMC10841163 DOI: 10.1002/cnm.3770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 08/02/2023] [Accepted: 08/18/2023] [Indexed: 09/10/2023]
Abstract
Recent publications report that although the mitochondria population in an axon can be quickly replaced by a combination of retrograde and anterograde axonal transport (often within less than 24 hours), the axon contains much older mitochondria. This suggests that not all mitochondria that reach the soma are degraded and that some are recirculating back into the axon. To explain this, we developed a model that simulates mitochondria distribution when a portion of mitochondria that return to the soma are redirected back to the axon rather than being destroyed in somatic lysosomes. Utilizing the developed model, we studied how the percentage of returning mitochondria affects the mean age and age density distributions of mitochondria at different distances from the soma. We also investigated whether turning off the mitochondrial anchoring switch can reduce the mean age of mitochondria. For this purpose, we studied the effect of reducing the value of a parameter that characterizes the probability of mitochondria transition to the stationary (anchored) state. The reduction in mitochondria mean age observed when the anchoring probability is reduced suggests that some injured neurons may be saved if the percentage of stationary mitochondria is decreased. The replacement of possibly damaged stationary mitochondria with newly synthesized ones may restore the energy supply in an injured axon. We also performed a sensitivity study of the mean age of stationary mitochondria to the parameter that determines what portion of mitochondria re-enter the axon and the parameter that determines the probability of mitochondria transition to the stationary state. The sensitivity of the mean age of stationary mitochondria to the mitochondria stopping probability increases linearly with the number of compartments in the axon. High stopping probability in long axons can significantly increase mitochondrial age.
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Affiliation(s)
- Ivan A Kuznetsov
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Andrey V Kuznetsov
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, USA
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21
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Nusir A, Sinclair P, Kabbani N. Mitochondrial Proteomes in Neural Cells: A Systematic Review. Biomolecules 2023; 13:1638. [PMID: 38002320 PMCID: PMC10669788 DOI: 10.3390/biom13111638] [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: 10/10/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
Mitochondria are ancient endosymbiotic double membrane organelles that support a wide range of eukaryotic cell functions through energy, metabolism, and cellular control. There are over 1000 known proteins that either reside within the mitochondria or are transiently associated with it. These mitochondrial proteins represent a functional subcellular protein network (mtProteome) that is encoded by mitochondrial and nuclear genomes and significantly varies between cell types and conditions. In neurons, the high metabolic demand and differential energy requirements at the synapses are met by specific modifications to the mtProteome, resulting in alterations in the expression and functional properties of the proteins involved in energy production and quality control, including fission and fusion. The composition of mtProteomes also impacts the localization of mitochondria in axons and dendrites with a growing number of neurodegenerative diseases associated with changes in mitochondrial proteins. This review summarizes the findings on the composition and properties of mtProteomes important for mitochondrial energy production, calcium and lipid signaling, and quality control in neural cells. We highlight strategies in mass spectrometry (MS) proteomic analysis of mtProteomes from cultured cells and tissue. The research into mtProteome composition and function provides opportunities in biomarker discovery and drug development for the treatment of metabolic and neurodegenerative disease.
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Affiliation(s)
- Aya Nusir
- Interdisciplinary Program in Neuroscience, School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
| | - Patricia Sinclair
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
| | - Nadine Kabbani
- Interdisciplinary Program in Neuroscience, School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
- School of Systems Biology, George Mason University, Fairfax, VA 22030, USA;
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22
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Myeong J, Stunault MI, Klyachko VA, Ashrafi G. Metabolic Regulation of Single Synaptic Vesicle Exo- and Endocytosis in Hippocampal Synapses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.566236. [PMID: 37986894 PMCID: PMC10659320 DOI: 10.1101/2023.11.08.566236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Glucose has long been considered a primary source of energy for synaptic function. However, it remains unclear under what conditions alternative fuels, such as lactate/pyruvate, contribute to powering synaptic transmission. By detecting individual release events in cultured hippocampal synapses, we found that mitochondrial ATP production from oxidation of lactate/pyruvate regulates basal vesicle release probability and release location within the active zone (AZ) evoked by single action potentials (APs). Mitochondrial inhibition shifted vesicle release closer to the AZ center, suggesting that the energetic barrier for vesicle release is lower in the AZ center that the periphery. Mitochondrial inhibition also altered the efficiency of single AP evoked vesicle retrieval by increasing occurrence of ultrafast endocytosis, while inhibition of glycolysis had no effect. Mitochondria are sparsely distributed along hippocampal axons and we found that nerve terminals containing mitochondria displayed enhanced vesicle release and reuptake during high-frequency trains, irrespective of whether neurons were supplied with glucose or lactate. Thus, synaptic terminals can entirely bypass glycolysis to robustly maintain the vesicle cycle using oxidative fuels in the absence of glucose. These observations further suggest that mitochondrial metabolic function not only regulates several fundamental features of synaptic transmission but may also contribute to modulation of short-term synaptic plasticity.
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Affiliation(s)
- Jongyun Myeong
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, 63132, United States
| | - Marion I Stunault
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, 63132, United States
| | - Vitaly A Klyachko
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, 63132, United States
| | - Ghazaleh Ashrafi
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO, 63132, United States
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, 63132, United States
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23
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Zuniga G, Frost B. Selective neuronal vulnerability to deficits in RNA processing. Prog Neurobiol 2023; 229:102500. [PMID: 37454791 DOI: 10.1016/j.pneurobio.2023.102500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 06/30/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Emerging evidence indicates that errors in RNA processing can causally drive neurodegeneration. Given that RNA produced from expressed genes of all cell types undergoes processing (splicing, polyadenylation, 5' capping, etc.), the particular vulnerability of neurons to deficits in RNA processing calls for careful consideration. The activity-dependent transcriptome remodeling associated with synaptic plasticity in neurons requires rapid, multilevel post-transcriptional RNA processing events that provide additional opportunities for dysregulation and consequent introduction or persistence of errors in RNA transcripts. Here we review the accumulating evidence that neurons have an enhanced propensity for errors in RNA processing alongside grossly insufficient defenses to clear misprocessed RNA compared to other cell types. Additionally, we explore how tau, a microtubule-associated protein implicated in Alzheimer's disease and related tauopathies, contributes to deficits in RNA processing and clearance.
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Affiliation(s)
- Gabrielle Zuniga
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, TX, USA; Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, TX, USA; Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Bess Frost
- Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, TX, USA; Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, University of Texas Health San Antonio, San Antonio, TX, USA; Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA.
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24
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Minckley TF, Salvagio LA, Fudge DH, Verhey K, Markus SM, Qin Y. Zn2+ decoration of microtubules arrests axonal transport and displaces tau, doublecortin, and MAP2C. J Cell Biol 2023; 222:e202208121. [PMID: 37326602 PMCID: PMC10276529 DOI: 10.1083/jcb.202208121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 03/31/2023] [Accepted: 05/11/2023] [Indexed: 06/17/2023] Open
Abstract
Intracellular Zn2+ concentrations increase via depolarization-mediated influx or intracellular release, but the immediate effects of Zn2+ signals on neuron function are not fully understood. By simultaneous recording of cytosolic Zn2+ and organelle motility, we find that elevated Zn2+ (IC50 ≈ 5-10 nM) reduces both lysosomal and mitochondrial motility in primary rat hippocampal neurons and HeLa cells. Using live-cell confocal microscopy and in vitro single-molecule TIRF imaging, we reveal that Zn2+ inhibits activity of motor proteins (kinesin and dynein) without disrupting their microtubule binding. Instead, Zn2+ directly binds to microtubules and selectively promotes detachment of tau, DCX, and MAP2C, but not MAP1B, MAP4, MAP7, MAP9, or p150glued. Bioinformatic predictions and structural modeling show that the Zn2+ binding sites on microtubules partially overlap with the microtubule binding sites of tau, DCX, dynein, and kinesin. Our results reveal that intraneuronal Zn2+ regulates axonal transport and microtubule-based processes by interacting with microtubules.
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Affiliation(s)
- Taylor F. Minckley
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | | | - Dylan H. Fudge
- Department of Biological Sciences, University of Denver, Denver, CO, USA
| | - Kristen Verhey
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Steven M. Markus
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Yan Qin
- Department of Biological Sciences, University of Denver, Denver, CO, USA
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25
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Yang S, Park JH, Lu HC. Axonal energy metabolism, and the effects in aging and neurodegenerative diseases. Mol Neurodegener 2023; 18:49. [PMID: 37475056 PMCID: PMC10357692 DOI: 10.1186/s13024-023-00634-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 06/08/2023] [Indexed: 07/22/2023] Open
Abstract
Human studies consistently identify bioenergetic maladaptations in brains upon aging and neurodegenerative disorders of aging (NDAs), such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and Amyotrophic lateral sclerosis. Glucose is the major brain fuel and glucose hypometabolism has been observed in brain regions vulnerable to aging and NDAs. Many neurodegenerative susceptible regions are in the topological central hub of the brain connectome, linked by densely interconnected long-range axons. Axons, key components of the connectome, have high metabolic needs to support neurotransmission and other essential activities. Long-range axons are particularly vulnerable to injury, neurotoxin exposure, protein stress, lysosomal dysfunction, etc. Axonopathy is often an early sign of neurodegeneration. Recent studies ascribe axonal maintenance failures to local bioenergetic dysregulation. With this review, we aim to stimulate research in exploring metabolically oriented neuroprotection strategies to enhance or normalize bioenergetics in NDA models. Here we start by summarizing evidence from human patients and animal models to reveal the correlation between glucose hypometabolism and connectomic disintegration upon aging/NDAs. To encourage mechanistic investigations on how axonal bioenergetic dysregulation occurs during aging/NDAs, we first review the current literature on axonal bioenergetics in distinct axonal subdomains: axon initial segments, myelinated axonal segments, and axonal arbors harboring pre-synaptic boutons. In each subdomain, we focus on the organization, activity-dependent regulation of the bioenergetic system, and external glial support. Second, we review the mechanisms regulating axonal nicotinamide adenine dinucleotide (NAD+) homeostasis, an essential molecule for energy metabolism processes, including NAD+ biosynthetic, recycling, and consuming pathways. Third, we highlight the innate metabolic vulnerability of the brain connectome and discuss its perturbation during aging and NDAs. As axonal bioenergetic deficits are developing into NDAs, especially in asymptomatic phase, they are likely exaggerated further by impaired NAD+ homeostasis, the high energetic cost of neural network hyperactivity, and glial pathology. Future research in interrogating the causal relationship between metabolic vulnerability, axonopathy, amyloid/tau pathology, and cognitive decline will provide fundamental knowledge for developing therapeutic interventions.
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Affiliation(s)
- Sen Yang
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Jung Hyun Park
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Hui-Chen Lu
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA.
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26
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Xu X, Li H, Lu S, Shen Y. Roles of syntaphilin and armadillo repeat-containing X-linked protein 1 in brain injury after experimental intracerebral hemorrhage. Neurosci Lett 2023; 809:137300. [PMID: 37187340 DOI: 10.1016/j.neulet.2023.137300] [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: 01/27/2023] [Revised: 04/15/2023] [Accepted: 05/12/2023] [Indexed: 05/17/2023]
Abstract
Studies have indicated that neuronal mitochondrial injury may be involved in the brain injury caused by intracerebral hemorrhage (ICH). Syntaphilin (SNPH) is associated with mitochondrial anchoring and Armadillo repeat-containing X-linked protein 1 (Armcx1) is linked to mitochondrial transport. This study aimed to analyze the contribution of SNPH and Armcx1 to the neuronal damage resulting from ICH. Primary cultured neuron cells were exposed to oxygenated hemoglobin to replicate the effects of ICH stimulation, while a mouse model of ICH was established by injecting autoblood into the basal ganglia. Specific SNPH knockout or Armcx1 overexpression in neurons is achieved by stereolocalization injection of adeno-associated virus vectors carrying hsyn specific promoters. First, it was confirmed that there is a correlation between SNPH/Armcx1 and ICH pathology, as evidenced by the rise of SNPH and the decrease of Armcx1 in neurons exposed to ICH both in vitro and in vivo. Second, our research revealed the protective effects of SNPH knockdown and Armcx1 overexpression on brain cell death around the hematoma in mice. In addition, the efficacy of SNPH knockdown and Armcx1 overexpression in improving neurobehavioral deficits was also demonstrated in mouse ICH model. Thus, moderate adjusting the levels of SNPH and Armcx1 may be an effective way to improve the outcome of ICH.
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Affiliation(s)
- Xiaowen Xu
- Department of Intensive Care Unit, The First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China
| | - Haiying Li
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou 215100, Jiangsu Province, China
| | - Shiqi Lu
- Department of Intensive Care Unit, The First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China.
| | - Yi Shen
- Department of Intensive Care Unit, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Suzhou 215002, Jiangsu Province, China.
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Wu Y, Ding C, Weinreb A, Manning L, Swaim G, Yogev S, Colón-Ramos DA, Hammarlund M. Polarized localization of kinesin-1 and RIC-7 drives axonal mitochondria anterograde transport. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.12.548706. [PMID: 37502914 PMCID: PMC10369933 DOI: 10.1101/2023.07.12.548706] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Mitochondria transport is crucial for mitochondria distribution in axons and is mediated by kinesin-1-based anterograde and dynein-based retrograde motor complexes. While Miro and Milton/TRAK were identified as key adaptors between mitochondria and kinesin-1, recent studies suggest the presence of additional mechanisms. In C. elegans, ric-7 is the only single gene described so far, other than kinesin-1, that is absolutely required for axonal mitochondria localization. Using CRISPR engineering in C. elegans, we find that Miro is important but is not essential for anterograde traffic, whereas it is required for retrograde traffic. Both the endogenous RIC-7 and kinesin-1 act at the leading end to transport mitochondria anterogradely. RIC-7 recruitment to mitochondria requires its N-terminal domain and partially relies on MIRO-1, whereas RIC-7 accumulation at the leading end depends on its disordered region, kinesin-1 and metaxin2. We conclude that polarized transport complexes containing kinesin-1 and RIC-7 form at the leading edge of mitochondria, and that these complexes are required for anterograde axonal transport.
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Affiliation(s)
- Youjun Wu
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06536, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Chen Ding
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Alexis Weinreb
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06536, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Laura Manning
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Grace Swaim
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Shaul Yogev
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Daniel A Colón-Ramos
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06536, USA
| | - Marc Hammarlund
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06536, USA
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06536, USA
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28
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Yang S, Niou ZX, Enriquez A, LaMar J, Huang JY, Ling K, Jafar-Nejad P, Gilley J, Coleman MP, Tennessen JM, Rangaraju V, Lu HC. NMNAT2 supports vesicular glycolysis via NAD homeostasis to fuel fast axonal transport. RESEARCH SQUARE 2023:rs.3.rs-2859584. [PMID: 37292715 PMCID: PMC10246254 DOI: 10.21203/rs.3.rs-2859584/v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Background Bioenergetic maladaptations and axonopathy are often found in the early stages of neurodegeneration. Nicotinamide adenine dinucleotide (NAD), an essential cofactor for energy metabolism, is mainly synthesized by Nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2) in CNS neurons. NMNAT2 mRNA levels are reduced in the brains of Alzheimer's, Parkinson's, and Huntington's disease. Here we addressed whether NMNAT2 is required for axonal health of cortical glutamatergic neurons, whose long-projecting axons are often vulnerable in neurodegenerative conditions. We also tested if NMNAT2 maintains axonal health by ensuring axonal ATP levels for axonal transport, critical for axonal function. Methods We generated mouse and cultured neuron models to determine the impact of NMNAT2 loss from cortical glutamatergic neurons on axonal transport, energetic metabolism, and morphological integrity. In addition, we determined if exogenous NAD supplementation or inhibiting a NAD hydrolase, sterile alpha and TIR motif-containing protein 1 (SARM1), prevented axonal deficits caused by NMNAT2 loss. This study used a combination of genetics, molecular biology, immunohistochemistry, biochemistry, fluorescent time-lapse imaging, live imaging with optical sensors, and anti-sense oligos. Results We provide in vivo evidence that NMNAT2 in glutamatergic neurons is required for axonal survival. Using in vivo and in vitro studies, we demonstrate that NMNAT2 maintains the NAD-redox potential to provide "on-board" ATP via glycolysis to vesicular cargos in distal axons. Exogenous NAD+ supplementation to NMNAT2 KO neurons restores glycolysis and resumes fast axonal transport. Finally, we demonstrate both in vitro and in vivo that reducing the activity of SARM1, an NAD degradation enzyme, can reduce axonal transport deficits and suppress axon degeneration in NMNAT2 KO neurons. Conclusion NMNAT2 ensures axonal health by maintaining NAD redox potential in distal axons to ensure efficient vesicular glycolysis required for fast axonal transport.
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Kuznetsov IA, Kuznetsov AV. Mitochondrial Transport in Symmetric and Asymmetric Axons with Multiple Branching Junctions: A Computational Study. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.22.529604. [PMID: 36865162 PMCID: PMC9980112 DOI: 10.1101/2023.02.22.529604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
We explore the impact of multiple branching junctions in axons on the mean age of mitochondria and their age density distributions in demand sites. The study looked at mitochondrial concentration, mean age, and age density distribution in relation to the distance from the soma. We developed models for a symmetric axon containing 14 demand sites and an asymmetric axon containing 10 demand sites. We examined how the concentration of mitochondria changes when an axon splits into two branches at the branching junction. We also studied whether mitochondria concentrations in the branches are affected by what proportion of mitochondrial flux enters the upper branch and what proportion of flux enters the lower branch. Additionally, we explored whether the distributions of mitochondria mean age and age density in branching axons are affected by how the mitochondrial flux splits at the branching junction. When the mitochondrial flux is split unevenly at the branching junction of an asymmetric axon, with a greater proportion of the flux entering the longer branch, the average age of mitochondria (system age) in the axon increases. Our findings elucidate the effects of axonal branching on mitochondria age. Mitochondria aging is the focus of this study as recent research suggests it may be involved in neurodegenerative disorders, such as Parkinson's disease.
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30
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Kuznetsov IA, Kuznetsov AV. ATP diffusional gradients are sufficient to maintain bioenergetic homeostasis in synaptic boutons lacking mitochondria. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2023; 39:e3696. [PMID: 36872253 DOI: 10.1002/cnm.3696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 05/13/2023]
Abstract
Previous work on mitochondrial distribution in axons has shown that approximately half of the presynaptic release sites do not contain mitochondria, raising the question of how the boutons that do not contain mitochondria are supplied with ATP. Here, we develop and apply a mathematical model to study this question. Specifically, we investigate whether diffusive transport of ATP is sufficient to support the exocytic functionality in synaptic boutons which lack mitochondria. Our results demonstrate that the difference in ATP concentration between a bouton containing a mitochondrion and a neighboring bouton lacking a mitochondrion is only approximately 0.4%, which is still 3.75 times larger than the ATP concentration minimally required to support synaptic vesicle release. This work therefore suggests that passive diffusion of ATP is sufficient to maintain the functionality of boutons which do not contain mitochondria.
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Affiliation(s)
- Ivan A Kuznetsov
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Andrey V Kuznetsov
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina, USA
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31
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Virga DM, Hamilton S, Osei B, Morgan A, Zamponi E, Park NJ, Hewitt VL, Zhang D, Gonzalez KC, Bloss E, Polleux F, Lewis TL. Activity-dependent subcellular compartmentalization of dendritic mitochondria structure in CA1 pyramidal neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.25.534233. [PMID: 36993655 PMCID: PMC10055421 DOI: 10.1101/2023.03.25.534233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Neuronal mitochondria play important roles beyond ATP generation, including Ca2+ uptake, and therefore have instructive roles in synaptic function and neuronal response properties. Mitochondrial morphology differs significantly in the axon and dendrites of a given neuronal subtype, but in CA1 pyramidal neurons (PNs) of the hippocampus, mitochondria within the dendritic arbor also display a remarkable degree of subcellular, layer-specific compartmentalization. In the dendrites of these neurons, mitochondria morphology ranges from highly fused and elongated in the apical tuft, to more fragmented in the apical oblique and basal dendritic compartments, and thus occupy a smaller fraction of dendritic volume than in the apical tuft. However, the molecular mechanisms underlying this striking degree of subcellular compartmentalization of mitochondria morphology are unknown, precluding the assessment of its impact on neuronal function. Here, we demonstrate that this compartment-specific morphology of dendritic mitochondria requires activity-dependent, Camkk2-dependent activation of AMPK and its ability to phosphorylate two direct effectors: the pro-fission Drp1 receptor Mff and the recently identified anti-fusion, Opa1-inhibiting protein, Mtfr1l. Our study uncovers a new activity-dependent molecular mechanism underlying the extreme subcellular compartmentalization of mitochondrial morphology in dendrites of neurons in vivo through spatially precise regulation of mitochondria fission/fusion balance.
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Affiliation(s)
- Daniel M. Virga
- Department of Neuroscience, Columbia Medical School, New York, NY- USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY- USA
| | - Stevie Hamilton
- Department of Neuroscience, Columbia Medical School, New York, NY- USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY- USA
| | - Bertha Osei
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - Abigail Morgan
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Neuroscience, Oklahoma University Health Science Campus, Oklahoma City, OK, USA
| | - Emiliano Zamponi
- Department of Neuroscience, Columbia Medical School, New York, NY- USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY- USA
| | - Natalie J. Park
- Department of Neuroscience, Columbia Medical School, New York, NY- USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY- USA
| | - Victoria L. Hewitt
- Department of Neuroscience, Columbia Medical School, New York, NY- USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY- USA
| | - David Zhang
- Department of Neuroscience, Columbia Medical School, New York, NY- USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY- USA
| | - Kevin C. Gonzalez
- Department of Neuroscience, Columbia Medical School, New York, NY- USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY- USA
| | - Erik Bloss
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Franck Polleux
- Department of Neuroscience, Columbia Medical School, New York, NY- USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY- USA
| | - Tommy L. Lewis
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
- Neuroscience, Oklahoma University Health Science Campus, Oklahoma City, OK, USA
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Optic Nerve Injury Enhanced Mitochondrial Fission and Increased Mitochondrial Density without Altering the Uniform Mitochondrial Distribution in the Unmyelinated Axons of Retinal Ganglion Cells in a Mouse Model. Int J Mol Sci 2023; 24:ijms24054356. [PMID: 36901786 PMCID: PMC10002508 DOI: 10.3390/ijms24054356] [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: 01/27/2023] [Revised: 02/17/2023] [Accepted: 02/20/2023] [Indexed: 02/25/2023] Open
Abstract
Glaucomatous optic neuropathy (GON), a major cause of blindness, is characterized by the loss of retinal ganglion cells (RGCs) and the degeneration of their axons. Mitochondria are deeply involved in maintaining the health of RGCs and their axons. Therefore, lots of attempts have been made to develop diagnostic tools and therapies targeting mitochondria. Recently, we reported that mitochondria are uniformly distributed in the unmyelinated axons of RGCs, possibly owing to the ATP gradient. Thus, using transgenic mice expressing yellow fluorescent protein targeting mitochondria exclusively in RGCs within the retina, we assessed the alteration of mitochondrial distributions induced by optic nerve crush (ONC) via in vitro flat-mount retinal sections and in vivo fundus images captured with a confocal scanning ophthalmoscope. We observed that the mitochondrial distribution in the unmyelinated axons of survived RGCs after ONC remained uniform, although their density increased. Furthermore, via in vitro analysis, we discovered that the mitochondrial size is attenuated following ONC. These results suggest that ONC induces mitochondrial fission without disrupting the uniform mitochondrial distribution, possibly preventing axonal degeneration and apoptosis. The in vivo visualization system of axonal mitochondria in RGCs may be applicable in the detection of the progression of GON in animal studies and potentially in humans.
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Dick F, Tysnes OB, Alves GW, Nido GS, Tzoulis C. Altered transcriptome-proteome coupling indicates aberrant proteostasis in Parkinson's disease. iScience 2023; 26:105925. [PMID: 36711240 PMCID: PMC9874017 DOI: 10.1016/j.isci.2023.105925] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/02/2022] [Accepted: 01/03/2023] [Indexed: 01/06/2023] Open
Abstract
Aberrant proteostasis is thought to be implicated in Parkinson's disease (PD), but patient-derived evidence is scant. We hypothesized that impaired proteostasis is reflected as altered transcriptome-proteome correlation in the PD brain. We integrated transcriptomic and proteomic data from prefrontal cortex of PD patients and young and aged controls to assess RNA-protein correlations across samples. The aged brain showed a genome-wide decrease in mRNA-protein correlation. Genes encoding synaptic vesicle proteins showed negative correlations, likely reflecting spatial separation of mRNA and protein into soma and synapses. PD showed a broader transcriptome-proteome decoupling, consistent with a proteome-wide decline in proteostasis. Genes showing negative correlation in PD were enriched for proteasome subunits, indicating accentuated spatial separation of transcript and protein in PD neurons. In addition, PD showed positive correlations for mitochondrial respiratory chain genes, suggesting a tighter regulation in the face of mitochondrial dysfunction. Our results support the hypothesis that aberrant proteasomal function is implicated in PD pathogenesis.
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Affiliation(s)
- Fiona Dick
- Neuro-SysMed Center of Excellence for Clinical Research in Neurological Diseases Department of Neurology, Haukeland University Hospital Department of Clinical Medicine, University of Bergen, 5021 Bergen, Norway
- K.G Jebsen Center for Translational Research in Parkinson’s disease, University of Bergen, Bergen, Norway
| | - Ole-Bjørn Tysnes
- Neuro-SysMed Center of Excellence for Clinical Research in Neurological Diseases Department of Neurology, Haukeland University Hospital Department of Clinical Medicine, University of Bergen, 5021 Bergen, Norway
| | - Guido W. Alves
- The Norwegian Center for Movement Disorders and Department of Neurology, Stavanger University Hospital, Stavanger, Norway
- Department of Mathematics and Natural Sciences, University of Stavanger, Stavanger, Norway
| | - Gonzalo S. Nido
- Neuro-SysMed Center of Excellence for Clinical Research in Neurological Diseases Department of Neurology, Haukeland University Hospital Department of Clinical Medicine, University of Bergen, 5021 Bergen, Norway
- K.G Jebsen Center for Translational Research in Parkinson’s disease, University of Bergen, Bergen, Norway
| | - Charalampos Tzoulis
- Neuro-SysMed Center of Excellence for Clinical Research in Neurological Diseases Department of Neurology, Haukeland University Hospital Department of Clinical Medicine, University of Bergen, 5021 Bergen, Norway
- K.G Jebsen Center for Translational Research in Parkinson’s disease, University of Bergen, Bergen, Norway
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O’Reilly CL, Miller BF, Lewis TL. Exercise and mitochondrial remodeling to prevent age-related neurodegeneration. J Appl Physiol (1985) 2023; 134:181-189. [PMID: 36519568 PMCID: PMC9829476 DOI: 10.1152/japplphysiol.00611.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Healthy brain activity requires precise ion and energy management creating a strong reliance on mitochondrial function. Age-related neurodegeneration leads to a decline in mitochondrial function and increased oxidative stress, with associated declines in mitochondrial mass, respiration capacity, and respiration efficiency. The interdependent processes of mitochondrial protein turnover and mitochondrial dynamics, known together as mitochondrial remodeling, play essential roles in mitochondrial health and therefore brain function. This mini-review describes the role of mitochondria in neurodegeneration and brain health, current practices for assessing both aspects of mitochondrial remodeling, and how exercise mitigates the adverse effects of aging in the brain. Exercise training elicits functional adaptations to improve brain health, and current literature strongly suggests that mitochondrial remodeling plays a vital role in these positive adaptations. Despite substantial implications that the two aspects of mitochondrial remodeling are interdependent, very few investigations have simultaneously measured mitochondrial dynamics and protein synthesis. An improved understanding of the partnership between mitochondrial protein turnover and mitochondrial dynamics will provide a better understanding of their role in both brain health and disease, as well as how they induce protection following exercise.
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Affiliation(s)
- Colleen L. O’Reilly
- 1Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
| | - Benjamin F. Miller
- 1Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma,2Oklahoma City Veterans Association, Oklahoma City, Oklahoma
| | - Tommy L. Lewis
- 1Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma
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35
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Tilokani L, Russell FM, Hamilton S, Virga DM, Segawa M, Paupe V, Gruszczyk AV, Protasoni M, Tabara LC, Johnson M, Anand H, Murphy MP, Hardie DG, Polleux F, Prudent J. AMPK-dependent phosphorylation of MTFR1L regulates mitochondrial morphology. SCIENCE ADVANCES 2022; 8:eabo7956. [PMID: 36367943 PMCID: PMC9651865 DOI: 10.1126/sciadv.abo7956] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Mitochondria are dynamic organelles that undergo membrane remodeling events in response to metabolic alterations to generate an adequate mitochondrial network. Here, we investigated the function of mitochondrial fission regulator 1-like protein (MTFR1L), an uncharacterized protein that has been identified in phosphoproteomic screens as a potential AMP-activated protein kinase (AMPK) substrate. We showed that MTFR1L is an outer mitochondrial membrane-localized protein modulating mitochondrial morphology. Loss of MTFR1L led to mitochondrial elongation associated with increased mitochondrial fusion events and levels of the mitochondrial fusion protein, optic atrophy 1. Mechanistically, we show that MTFR1L is phosphorylated by AMPK, which thereby controls the function of MTFR1L in regulating mitochondrial morphology both in mammalian cell lines and in murine cortical neurons in vivo. Furthermore, we demonstrate that MTFR1L is required for stress-induced AMPK-dependent mitochondrial fragmentation. Together, these findings identify MTFR1L as a critical mitochondrial protein transducing AMPK-dependent metabolic changes through regulation of mitochondrial dynamics.
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Affiliation(s)
- Lisa Tilokani
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, CB2 0XY Cambridge, UK
| | - Fiona M. Russell
- Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | - Stevie Hamilton
- Department of Neuroscience, Columbia University, New York, NY 10032, USA
| | - Daniel M. Virga
- Department of Neuroscience, Columbia University, New York, NY 10032, USA
| | - Mayuko Segawa
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, CB2 0XY Cambridge, UK
| | - Vincent Paupe
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, CB2 0XY Cambridge, UK
| | - Anja V. Gruszczyk
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, CB2 0XY Cambridge, UK
| | - Margherita Protasoni
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, CB2 0XY Cambridge, UK
| | - Luis-Carlos Tabara
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, CB2 0XY Cambridge, UK
| | - Mark Johnson
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, CB2 0XY Cambridge, UK
| | - Hanish Anand
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, CB2 0XY Cambridge, UK
| | - Michael P. Murphy
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, CB2 0XY Cambridge, UK
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - D. Grahame Hardie
- Division of Cell Signalling & Immunology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | - Franck Polleux
- Department of Neuroscience, Columbia University, New York, NY 10032, USA
| | - Julien Prudent
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Hills Road, CB2 0XY Cambridge, UK
- Corresponding author.
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36
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Kim SY, Strucinska K, Osei B, Han K, Kwon SK, Lewis TL. Neuronal mitochondrial morphology is significantly affected by both fixative and oxygen level during perfusion. Front Mol Neurosci 2022; 15:1042616. [PMID: 36407767 PMCID: PMC9667081 DOI: 10.3389/fnmol.2022.1042616] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/17/2022] [Indexed: 03/31/2023] Open
Abstract
Neurons in the brain have a uniquely polarized structure consisting of multiple dendrites and a single axon generated from a cell body. Interestingly, intracellular mitochondria also show strikingly polarized morphologies along the dendrites and axons: in cortical pyramidal neurons (PNs), dendritic mitochondria have a long and tubular shape, while axonal mitochondria are small and circular. Mitochondria play important roles in each compartment of the neuron by generating adenosine triphosphate (ATP) and buffering calcium, thereby affecting synaptic transmission and neuronal development. In addition, mitochondrial shape, and thereby function, is dynamically altered by environmental stressors such as oxidative stress or in various neurodegenerative diseases including Alzheimer's disease and Parkinson's disease. Although the importance of altered mitochondrial shape has been claimed by multiple studies, methods for studying this stress-sensitive organelle have not been standardized. Here we address pertinent steps that influence mitochondrial morphology during experimental processes. We demonstrate that fixative solutions containing only paraformaldehyde (PFA), or that introduce hypoxic conditions during the procedure, induce dramatic fragmentation of mitochondria both in vitro and in vivo. This disruption was not observed following the use of glutaraldehyde (GA) addition or oxygen supplementation, respectively. Finally, using pre-formed fibril α-synuclein treated neurons, we show fixative choice can alter experimental outcomes. Specifically, α-synuclein-induced mitochondrial remodeling could not be observed with PFA only fixation as fixation itself caused mitochondrial fragmentation. Our study provides optimized methods for examining mitochondrial morphology in neurons and demonstrates that fixation conditions are critical when investigating the underlying cellular mechanisms involving mitochondria in physiological and neurodegenerative disease models.
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Affiliation(s)
- Su Yeon Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea
- Department of Neuroscience, College of Medicine, Korea University, Seoul, South Korea
| | - Klaudia Strucinska
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Bertha Osei
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
| | - Kihoon Han
- Department of Neuroscience, College of Medicine, Korea University, Seoul, South Korea
| | - Seok-Kyu Kwon
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, South Korea
- Division of Bio-Medical Science and Technology, KIST School, Korea University of Science and Technology (UST), Daejeon, South Korea
| | - Tommy L. Lewis
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, United States
- Departments of Biochemistry & Molecular Biology, Neuroscience and Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
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37
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Kuznetsov IA, Kuznetsov AV. Effects of axon branching and asymmetry between the branches on transport, mean age, and age density distributions of mitochondria in neurons: A computational study. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3648. [PMID: 36125402 PMCID: PMC9643662 DOI: 10.1002/cnm.3648] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 08/17/2022] [Accepted: 09/04/2022] [Indexed: 06/15/2023]
Abstract
We report a computational study of mitochondria transport in a branched axon with two branches of different sizes. For comparison, we also investigate mitochondria transport in an axon with symmetric branches and in a straight (unbranched) axon. The interest in understanding mitochondria transport in branched axons is motivated by the large size of arbors of dopaminergic neurons, which die in Parkinson's disease. Since the failure of energy supply of multiple demand sites located in various axonal branches may be a possible reason for the death of these neurons, we were interested in investigating how branching affects mitochondria transport. Besides investigating mitochondria fluxes between the demand sites and mitochondria concentrations, we also studied how the mean age of mitochondria and mitochondria age densities depend on the distance from the soma. We established that if the axon splits into two branches of unequal length, the mean ages of mitochondria and age density distributions in the demand sites are affected by how the mitochondria flux splits at the branching junction (what portion of mitochondria enter the shorter branch and what portion enter the longer branch). However, if the axon splits into two branches of equal length, the mean ages and age densities of mitochondria are independent of how the mitochondria flux splits at the branching junction. This even holds for the case when all mitochondria enter one branch, which is equivalent to a straight axon. Because the mitochondrial membrane potential (which many researchers view as a proxy for mitochondrial health) decreases with mitochondria age, the independence of mitochondria age on whether the axon is symmetrically branched or straight (providing the two axons are of the same length), and on how the mitochondria flux splits at the branching junction, may explain how dopaminergic neurons can sustain very large arbors and still maintain mitochondrial health across branch extremities.
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Affiliation(s)
- Ivan A. Kuznetsov
- Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Andrey V. Kuznetsov
- Department of Mechanical and Aerospace EngineeringNorth Carolina State UniversityRaleighNorth CarolinaUSA
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38
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Abstract
The analogy of mitochondria as powerhouses has expired. Mitochondria are living, dynamic, maternally inherited, energy-transforming, biosynthetic, and signaling organelles that actively transduce biological information. We argue that mitochondria are the processor of the cell, and together with the nucleus and other organelles they constitute the mitochondrial information processing system (MIPS). In a three-step process, mitochondria (1) sense and respond to both endogenous and environmental inputs through morphological and functional remodeling; (2) integrate information through dynamic, network-based physical interactions and diffusion mechanisms; and (3) produce output signals that tune the functions of other organelles and systemically regulate physiology. This input-to-output transformation allows mitochondria to transduce metabolic, biochemical, neuroendocrine, and other local or systemic signals that enhance organismal adaptation. An explicit focus on mitochondrial signal transduction emphasizes the role of communication in mitochondrial biology. This framework also opens new avenues to understand how mitochondria mediate inter-organ processes underlying human health.
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Affiliation(s)
- Martin Picard
- Department of Psychiatry, Division of Behavioral Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Neurology, H. Houston Merritt Center, Columbia Translational Neuroscience Initiative, Columbia University Irving Medical Center, New York, NY 10032, USA; New York State Psychiatric Institute, New York, NY 10032, USA.
| | - Orian S Shirihai
- Department of Medicine, Endocrinology, and Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA; Metabolism Theme, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095, USA
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39
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A small molecule M1 promotes optic nerve regeneration to restore target-specific neural activity and visual function. Proc Natl Acad Sci U S A 2022; 119:e2121273119. [PMID: 36306327 PMCID: PMC9636930 DOI: 10.1073/pnas.2121273119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Axon regeneration is an energy-demanding process that requires active mitochondrial transport. In contrast to the central nervous system (CNS), axonal mitochondrial transport in regenerating axons of the peripheral nervous system (PNS) increases within hours and sustains for weeks after injury. Yet, little is known about targeting mitochondria in nervous system repair. Here, we report the induction of sustained axon regeneration, neural activities in the superior colliculus (SC), and visual function recovery after optic nerve crush (ONC) by M1, a small molecule that promotes mitochondrial fusion and transport. We demonstrated that M1 enhanced mitochondrial dynamics in cultured neurons and accelerated in vivo axon regeneration in the PNS. Ex vivo time-lapse imaging and kymograph analysis showed that M1 greatly increased mitochondrial length, axonal mitochondrial motility, and transport velocity in peripheral axons of the sciatic nerves. Following ONC, M1 increased the number of axons regenerating through the optic chiasm into multiple subcortical areas and promoted the recovery of local field potentials in the SC after optogenetic stimulation of retinal ganglion cells, resulting in complete recovery of the pupillary light reflex, and restoration of the response to looming visual stimuli was detected. M1 increased the gene expression of mitochondrial fusion proteins and major axonal transport machinery in both the PNS and CNS neurons without inducing inflammatory responses. The knockdown of two key mitochondrial genes,
Opa1
or
Mfn2
, abolished the growth-promoting effects of M1 after ONC, suggesting that maintaining a highly dynamic mitochondrial population in axons is required for successful CNS axon regeneration.
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40
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The compartmentalised nature of neuronal mitophagy: molecular insights and implications. Expert Rev Mol Med 2022; 24:e38. [PMID: 36172898 PMCID: PMC9884780 DOI: 10.1017/erm.2022.31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The maintenance of a healthy mitochondrial network and the ability to adjust organelle population in response to internal or external stimuli are essential for the function and the survival of eukaryotic cells. Over the last two decades several studies have demonstrated the paramount importance of mitophagy, a selective form of autophagy that removes damaged and/or superfluous organelles, in organismal physiology. Post-mitotic neuronal cells are particularly vulnerable to mitochondrial damage, and mitophagy impairment has emerged as a causative factor in multiple neurodegenerative pathologies, including Alzheimer's disease and Parkinson's disease among others. Although mitochondrial turnover is a multifaceted process, neurons have to tackle additional complications, arising from their pronounced bioenergetic demands and their unique architecture and cellular polarisation that render the degradation of distal organelles challenging. Mounting evidence indicates that despite the functional conservation of mitophagy pathways, the unique features of neuronal physiology have led to the adaptation of compartmentalised solutions, which serve to ensure seamless mitochondrial removal in every part of the cell. In this review, we summarise the current knowledge concerning the molecular mechanisms that mediate mitophagy compartmentalisation and discuss their implications in various human pathologies.
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41
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Kiryu-Seo S, Matsushita R, Tashiro Y, Yoshimura T, Iguchi Y, Katsuno M, Takahashi R, Kiyama H. Impaired disassembly of the axon initial segment restricts mitochondrial entry into damaged axons. EMBO J 2022; 41:e110486. [PMID: 36004759 PMCID: PMC9574747 DOI: 10.15252/embj.2021110486] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 07/15/2022] [Accepted: 07/20/2022] [Indexed: 11/09/2022] Open
Abstract
The proteasome is essential for cellular responses to various physiological stressors. However, how proteasome function impacts the stress resilience of regenerative damaged motor neurons remains unclear. Here, we develop a unique mouse model using a regulatory element of the activating transcription factor (Atf3) gene to label mitochondria in a damage‐induced manner while simultaneously genetically disrupting the proteasome. Using this model, we observed that in injury‐induced proteasome‐deficient mouse motor neurons, the increase of mitochondrial influx from soma into axons is inhibited because neurons fail to disassemble ankyrin G, an organizer of the axon initial segment (AIS), in a proteasome‐dependent manner. Further, these motor neurons exhibit amyotrophic lateral sclerosis (ALS)‐like degeneration despite having regenerative potential. Selectively vulnerable motor neurons in SOD1G93A ALS mice, which induce ATF3 in response to pathological damage, also fail to disrupt the AIS, limiting the number of axonal mitochondria at a pre‐symptomatic stage. Thus, damage‐induced proteasome‐sensitive AIS disassembly could be a critical post‐translational response for damaged motor neurons to temporarily transit to an immature state and meet energy demands for axon regeneration or preservation.
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Affiliation(s)
- Sumiko Kiryu-Seo
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Reika Matsushita
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yoshitaka Tashiro
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Takeshi Yoshimura
- Department of Child Development and Molecular Brain Science, United Graduate School of Child Development, Osaka University, Osaka, Japan.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Yohei Iguchi
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Masahisa Katsuno
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Ryosuke Takahashi
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hiroshi Kiyama
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
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42
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Pozo Devoto VM, Onyango IG, Stokin GB. Mitochondrial behavior when things go wrong in the axon. Front Cell Neurosci 2022; 16:959598. [PMID: 35990893 PMCID: PMC9389222 DOI: 10.3389/fncel.2022.959598] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Axonal homeostasis is maintained by processes that include cytoskeletal regulation, cargo transport, synaptic activity, ionic balance, and energy supply. Several of these processes involve mitochondria to varying degrees. As a transportable powerplant, the mitochondria deliver ATP and Ca2+-buffering capabilities and require fusion/fission to maintain proper functioning. Taking into consideration the long distances that need to be covered by mitochondria in the axons, their transport, distribution, fusion/fission, and health are of cardinal importance. However, axonal homeostasis is disrupted in several disorders of the nervous system, or by traumatic brain injury (TBI), where the external insult is translated into physical forces that damage nervous tissue including axons. The degree of damage varies and can disconnect the axon into two segments and/or generate axonal swellings in addition to cytoskeletal changes, membrane leakage, and changes in ionic composition. Cytoskeletal changes and increased intra-axonal Ca2+ levels are the main factors that challenge mitochondrial homeostasis. On the other hand, a proper function and distribution of mitochondria can determine the recovery or regeneration of the axonal physiological state. Here, we discuss the current knowledge regarding mitochondrial transport, fusion/fission, and Ca2+ regulation under axonal physiological or pathological conditions.
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Affiliation(s)
- Victorio M. Pozo Devoto
- Translational Neuroscience and Ageing Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czechia
| | - Isaac G. Onyango
- Translational Neuroscience and Ageing Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czechia
| | - Gorazd B. Stokin
- Translational Neuroscience and Ageing Program, Centre for Translational Medicine, International Clinical Research Centre, St. Anne's University Hospital, Brno, Czechia
- Division of Neurology, University Medical Centre, Ljubljana, Slovenia
- Department of Neurosciences, Mayo Clinic, Rochester, MN, United States
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43
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Lee A, Kondapalli C, Virga DM, Lewis TL, Koo SY, Ashok A, Mairet-Coello G, Herzig S, Foretz M, Viollet B, Shaw R, Sproul A, Polleux F. Aβ42 oligomers trigger synaptic loss through CAMKK2-AMPK-dependent effectors coordinating mitochondrial fission and mitophagy. Nat Commun 2022; 13:4444. [PMID: 35915085 PMCID: PMC9343354 DOI: 10.1038/s41467-022-32130-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 07/18/2022] [Indexed: 12/23/2022] Open
Abstract
During the early stages of Alzheimer's disease (AD) in both mouse models and human patients, soluble forms of Amyloid-β 1-42 oligomers (Aβ42o) trigger loss of excitatory synapses (synaptotoxicity) in cortical and hippocampal pyramidal neurons (PNs) prior to the formation of insoluble amyloid plaques. In a transgenic AD mouse model, we observed a spatially restricted structural remodeling of mitochondria in the apical tufts of CA1 PNs dendrites corresponding to the dendritic domain where the earliest synaptic loss is detected in vivo. We also observed AMPK over-activation as well as increased fragmentation and loss of mitochondrial biomass in Ngn2-induced neurons derived from a new APPSwe/Swe knockin human ES cell line. We demonstrate that Aβ42o-dependent over-activation of the CAMKK2-AMPK kinase dyad mediates synaptic loss through coordinated phosphorylation of MFF-dependent mitochondrial fission and ULK2-dependent mitophagy. Our results uncover a unifying stress-response pathway causally linking Aβ42o-dependent structural remodeling of dendritic mitochondria to synaptic loss.
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Affiliation(s)
- Annie Lee
- Department of Neuroscience, Columbia University Medical Center New York, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, New York, NY, USA
- The Integrated Graduate Program in Cellular, Molecular, and Biomedical Studies, Columbia University Medical Center, New York, NY, USA
| | - Chandana Kondapalli
- Department of Neuroscience, Columbia University Medical Center New York, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, New York, NY, USA
| | - Daniel M Virga
- Department of Neuroscience, Columbia University Medical Center New York, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, New York, NY, USA
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Tommy L Lewis
- Department of Neuroscience, Columbia University Medical Center New York, New York, NY, USA
- Mortimer B. Zuckerman Mind Brain Behavior Institute, New York, NY, USA
- Aging & Metabolism Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, USA
| | - So Yeon Koo
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
| | - Archana Ashok
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
| | | | - Sebastien Herzig
- Molecular & Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Marc Foretz
- Institut Cochin, Université de Paris, CNRS, INSERM, Paris, France
| | - Benoit Viollet
- Institut Cochin, Université de Paris, CNRS, INSERM, Paris, France
| | - Reuben Shaw
- Molecular & Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Andrew Sproul
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, NY, USA
- Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY, USA
| | - Franck Polleux
- Department of Neuroscience, Columbia University Medical Center New York, New York, NY, USA.
- Mortimer B. Zuckerman Mind Brain Behavior Institute, New York, NY, USA.
- Kavli Institute for Brain Sciences, Columbia University Medical Center, New York, NY, USA.
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44
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Pekkurnaz G, Wang X. Mitochondrial heterogeneity and homeostasis through the lens of a neuron. Nat Metab 2022; 4:802-812. [PMID: 35817853 PMCID: PMC11151822 DOI: 10.1038/s42255-022-00594-w] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 05/23/2022] [Indexed: 12/12/2022]
Abstract
Mitochondria are vital organelles with distinct morphological features and functional properties. The dynamic network of mitochondria undergoes structural and functional adaptations in response to cell-type-specific metabolic demands. Even within the same cell, mitochondria can display wide diversity and separate into functionally distinct subpopulations. Mitochondrial heterogeneity supports unique subcellular functions and is crucial to polarized cells, such as neurons. The spatiotemporal metabolic burden within the complex shape of a neuron requires precisely localized mitochondria. By travelling great lengths throughout neurons and experiencing bouts of immobility, mitochondria meet distant local fuel demands. Understanding mitochondrial heterogeneity and homeostasis mechanisms in neurons provides a framework to probe their significance to many other cell types. Here, we put forth an outline of the multifaceted role of mitochondria in regulating neuronal physiology and cellular functions more broadly.
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Affiliation(s)
- Gulcin Pekkurnaz
- Neurobiology Department, School of Biological Sciences, University of California San Diego, La Jolla, CA, USA.
| | - Xinnan Wang
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, USA.
- Wu Tsai Neurosciences Institute, Stanford University School of Medicine, Stanford, CA, USA.
- Maternal & Child Health Research Institute, Stanford University School of Medicine, Stanford, CA, USA.
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45
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Single-dose ethanol intoxication causes acute and lasting neuronal changes in the brain. Proc Natl Acad Sci U S A 2022; 119:e2122477119. [PMID: 35700362 DOI: 10.1073/pnas.2122477119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Alcohol intoxication at early ages is a risk factor for the development of addictive behavior. To uncover neuronal molecular correlates of acute ethanol intoxication, we used stable-isotope-labeled mice combined with quantitative mass spectrometry to screen more than 2,000 hippocampal proteins, of which 72 changed synaptic abundance up to twofold after ethanol exposure. Among those were mitochondrial proteins and proteins important for neuronal morphology, including MAP6 and ankyrin-G. Based on these candidate proteins, we found acute and lasting molecular, cellular, and behavioral changes following a single intoxication in alcohol-naïve mice. Immunofluorescence analysis revealed a shortening of axon initial segments. Longitudinal two-photon in vivo imaging showed increased synaptic dynamics and mitochondrial trafficking in axons. Knockdown of mitochondrial trafficking in dopaminergic neurons abolished conditioned alcohol preference in Drosophila flies. This study introduces mitochondrial trafficking as a process implicated in reward learning and highlights the potential of high-resolution proteomics to identify cellular mechanisms relevant for addictive behavior.
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46
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Cheng XT, Huang N, Sheng ZH. Programming axonal mitochondrial maintenance and bioenergetics in neurodegeneration and regeneration. Neuron 2022; 110:1899-1923. [PMID: 35429433 PMCID: PMC9233091 DOI: 10.1016/j.neuron.2022.03.015] [Citation(s) in RCA: 73] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/04/2022] [Accepted: 03/10/2022] [Indexed: 12/11/2022]
Abstract
Mitochondria generate ATP essential for neuronal growth, function, and regeneration. Due to their polarized structures, neurons face exceptional challenges to deliver mitochondria to and maintain energy homeostasis throughout long axons and terminal branches where energy is in high demand. Chronic mitochondrial dysfunction accompanied by bioenergetic failure is a pathological hallmark of major neurodegenerative diseases. Brain injury triggers acute mitochondrial damage and a local energy crisis that accelerates neuron death. Thus, mitochondrial maintenance defects and axonal energy deficits emerge as central problems in neurodegenerative disorders and brain injury. Recent studies have started to uncover the intrinsic mechanisms that neurons adopt to maintain (or reprogram) axonal mitochondrial density and integrity, and their bioenergetic capacity, upon sensing energy stress. In this review, we discuss recent advances in how neurons maintain a healthy pool of axonal mitochondria, as well as potential therapeutic strategies that target bioenergetic restoration to power neuronal survival, function, and regeneration.
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Affiliation(s)
- Xiu-Tang Cheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA
| | - Ning Huang
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA
| | - Zu-Hang Sheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, MD 20892-3706, USA.
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47
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Ketschek A, Holland SM, Gallo G. SARM1 Suppresses Axon Branching Through Attenuation of Axonal Cytoskeletal Dynamics. Front Mol Neurosci 2022; 15:726962. [PMID: 35264929 PMCID: PMC8899016 DOI: 10.3389/fnmol.2022.726962] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 01/20/2022] [Indexed: 12/18/2022] Open
Abstract
Axon branching is a fundamental aspect of neuronal morphogenesis, neuronal circuit formation, and response of the nervous system to injury. Sterile alpha and TIR motif containing 1 (SARM1) was initially identified as promoting Wallerian degeneration of axons. We now report a novel function of SARM1 in postnatal sensory neurons; the suppression of axon branching. Axon collateral branches develop from axonal filopodia precursors through the coordination of the actin and microtubule cytoskeleton. In vitro analysis revealed that cultured P0-2 dorsal root ganglion sensory neurons from a SARM1 knockout (KO) mouse exhibit increased numbers of collateral branches and axonal filopodia relative to wild-type neurons. In SARM1 KO mice, cutaneous sensory endings exhibit increased branching in the skin in vivo with normal density of innervation. Transient axonal actin patches serve as cytoskeletal platforms from which axonal filopodia emerge. Live imaging analysis of axonal actin dynamics showed that SARM1 KO neurons exhibit increased rates of axonal actin patch formation and increased probability that individual patches will give rise to a filopodium before dissipating. SARM1 KO axons contain elevated levels of drebrin and cortactin, two actin regulatory proteins that are positive regulators of actin patches, filopodia formation, and branching. Live imaging of microtubule plus tip dynamics revealed an increase in the rate of formation and velocity of polymerizing tips along the axons of SARM1 KO neurons. Stationary mitochondria define sites along the axon where branches may arise, and the axons of SARM1 KO sensory neurons exhibit an increase in stationary mitochondria. These data reveal SARM1 to be a negative regulator of axonal cytoskeletal dynamics and collateral branching.
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Affiliation(s)
- Andrea Ketschek
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Sabrina M. Holland
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
| | - Gianluca Gallo
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
- Department of Neural Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, United States
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Matsumoto N, Hori I, Kajita MK, Murase T, Nakamura W, Tsuji T, Miyake S, Inatani M, Konishi Y. Intermitochondrial signaling regulates the uniform distribution of stationary mitochondria in axons. Mol Cell Neurosci 2022; 119:103704. [DOI: 10.1016/j.mcn.2022.103704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 12/27/2021] [Accepted: 01/31/2022] [Indexed: 10/19/2022] Open
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Abstract
Visualization and analysis of axonal organelle transport has been mostly conducted in vitro, using primary neuronal cell cultures, although more recently, intravital organelle imaging has been established in model organisms such as drosophila, zebrafish, and mouse. In this chapter, we describe a method to visualize axonal transport of cellular organelles such as dense core vesicles or mitochondria in the living mouse brain in order to study organelle transport in its native environment. We achieve this goal by injecting adeno-associated viruses expressing fluorescently tagged marker proteins into thalamic nuclei of mice, thereby transducing neurons that project to the surface of the brain. Axonal projections and trafficking of organelles can be imaged with a 2-photon microscope through a chronically implanted window in the mouse skull in anesthetized as well as awake mice.
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Affiliation(s)
- Johannes Knabbe
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany.
- Center for Psychosocial Medicine, Department of General Psychiatry, Heidelberg University Hospital, Heidelberg, Germany.
| | - Jil Protzmann
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
- Karolinska Institutet, Department of Medical Biochemistry and Biophysics, Stockholm, Sweden
| | - Thomas Kuner
- Department of Functional Neuroanatomy, Institute for Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
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50
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Mitochondrial Biogenesis in Neurons: How and Where. Int J Mol Sci 2021; 22:ijms222313059. [PMID: 34884861 PMCID: PMC8657637 DOI: 10.3390/ijms222313059] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 11/27/2021] [Accepted: 11/29/2021] [Indexed: 11/27/2022] Open
Abstract
Neurons rely mostly on mitochondria for the production of ATP and Ca2+ homeostasis. As sub-compartmentalized cells, they have different pools of mitochondria in each compartment that are maintained by a constant mitochondrial turnover. It is assumed that most mitochondria are generated in the cell body and then travel to the synapse to exert their functions. Once damaged, mitochondria have to travel back to the cell body for degradation. However, in long cells, like motor neurons, this constant travel back and forth is not an energetically favourable process, thus mitochondrial biogenesis must also occur at the periphery. Ca2+ and ATP levels are the main triggers for mitochondrial biogenesis in the cell body, in a mechanism dependent on the Peroxisome-proliferator-activated γ co-activator-1α-nuclear respiration factors 1 and 2-mitochondrial transcription factor A (PGC-1α-NRF-1/2-TFAM) pathway. However, even though of extreme importance, very little is known about the mechanisms promoting mitochondrial biogenesis away from the cell body. In this review, we bring forward the evoked mechanisms that are at play for mitochondrial biogenesis in the cell body and periphery. Moreover, we postulate that mitochondrial biogenesis may vary locally within the same neuron, and we build upon the hypotheses that, in the periphery, local protein synthesis is responsible for giving all the machinery required for mitochondria to replicate themselves.
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