1
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Shen Y, Li X, Wang H, Wang Y, Tao L, Wang P, Zhang H. Bisphenol A induced neuronal apoptosis and enhanced autophagy in vitro through Nrf2/HO-1 and Akt/mTOR pathways. Toxicology 2023; 500:153678. [PMID: 38006930 DOI: 10.1016/j.tox.2023.153678] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/10/2023] [Accepted: 11/18/2023] [Indexed: 11/27/2023]
Abstract
Bisphenol A (BPA) was traditionally used in epoxy resins and polycarbonate plastics, but it was found to be harmful to human health due to its endocrine-disrupting effects. It can affect various biological functions of human beings and interfere with brain development. However, the neurotoxic mechanisms of BPA on brain development and associated neurodegeneration remain poorly understood. Here, we reported that BPA (100, 250, 500 μM) inhibited cell viability of neural cells PC12, SH-SY5Y and caused dose-dependent cell death. In addition, BPA exposure increased intracellular reactive oxygen species (ROS) and mitochondrial ROS (mtROS) levels, decreased mitochondrial membrane potential, reduced the expression of cytochrome c oxidase IV (COX4), downregulated Bcl-2, and initiated apoptosis. Moreover, BPA treatment resulted in the accumulation of intracellular acidic vacuoles and increased the autophagy marker LC3 II to LC3 I ratio. Furthermore, BPA exposure inhibited Nrf2/ HO-1 and AKT/mTOR pathways and mediated cellular oxidative stress, apoptosis, and excessive autophagy, leading to neuronal degeneration. The interactions between oxidative stress, autophagy, and apoptosis during BPA-induced neurotoxicity remain unclear and require further in vivo confirmation.
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Affiliation(s)
- Yue Shen
- Neurodegeneration and Neuroregeneration Laboratory, Department of Basic Medicine, School of Medicine, Shaoxing University, Shaoxing, Zhejiang, China
| | - Xinying Li
- Neurodegeneration and Neuroregeneration Laboratory, Department of Basic Medicine, School of Medicine, Shaoxing University, Shaoxing, Zhejiang, China
| | - Hongyan Wang
- Neurodegeneration and Neuroregeneration Laboratory, Department of Basic Medicine, School of Medicine, Shaoxing University, Shaoxing, Zhejiang, China
| | - Yicheng Wang
- Neurodegeneration and Neuroregeneration Laboratory, Department of Basic Medicine, School of Medicine, Shaoxing University, Shaoxing, Zhejiang, China
| | - Liqing Tao
- Neurodegeneration and Neuroregeneration Laboratory, Department of Basic Medicine, School of Medicine, Shaoxing University, Shaoxing, Zhejiang, China; School of Life Sciences, Shaoxing University, Shaoxing, Zhejiang, China
| | - Pingping Wang
- Neurodegeneration and Neuroregeneration Laboratory, Department of Basic Medicine, School of Medicine, Shaoxing University, Shaoxing, Zhejiang, China
| | - Heng Zhang
- Neurodegeneration and Neuroregeneration Laboratory, Department of Basic Medicine, School of Medicine, Shaoxing University, Shaoxing, Zhejiang, China; School of Life Sciences, Shaoxing University, Shaoxing, Zhejiang, China.
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2
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Piol D, Robberechts T, Da Cruz S. Lost in local translation: TDP-43 and FUS in axonal/neuromuscular junction maintenance and dysregulation in amyotrophic lateral sclerosis. Neuron 2023; 111:1355-1380. [PMID: 36963381 DOI: 10.1016/j.neuron.2023.02.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 12/21/2022] [Accepted: 02/16/2023] [Indexed: 03/26/2023]
Abstract
Key early features of amyotrophic lateral sclerosis (ALS) are denervation of neuromuscular junctions and axonal degeneration. Motor neuron homeostasis relies on local translation through controlled regulation of axonal mRNA localization, transport, and stability. Yet the composition of the local transcriptome, translatome (mRNAs locally translated), and proteome during health and disease remains largely unexplored. This review covers recent discoveries on axonal translation as a critical mechanism for neuronal maintenance/survival. We focus on two RNA binding proteins, transactive response DNA binding protein-43 (TDP-43) and fused in sarcoma (FUS), whose mutations cause ALS and frontotemporal dementia (FTD). Emerging evidence points to their essential role in the maintenance of axons and synapses, including mRNA localization, transport, and local translation, and whose dysfunction may contribute to ALS. Finally, we describe recent advances in omics-based approaches mapping compartment-specific local RNA and protein compositions, which will be invaluable to elucidate fundamental local processes and identify key targets for therapy development.
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Affiliation(s)
- Diana Piol
- VIB-KU Leuven Center for Brain and Disease Research, Department of Neurosciences, KU Leuven, Leuven Brain Institute, Leuven, Belgium
| | - Tessa Robberechts
- VIB-KU Leuven Center for Brain and Disease Research, Department of Neurosciences, KU Leuven, Leuven Brain Institute, Leuven, Belgium
| | - Sandrine Da Cruz
- VIB-KU Leuven Center for Brain and Disease Research, Department of Neurosciences, KU Leuven, Leuven Brain Institute, Leuven, Belgium.
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3
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Hees JT, Harbauer AB. Metabolic Regulation of Mitochondrial Protein Biogenesis from a Neuronal Perspective. Biomolecules 2022; 12:1595. [PMID: 36358945 PMCID: PMC9687362 DOI: 10.3390/biom12111595] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 09/29/2023] Open
Abstract
Neurons critically depend on mitochondria for ATP production and Ca2+ buffering. They are highly compartmentalized cells and therefore a finely tuned mitochondrial network constantly adapting to the local requirements is necessary. For neuronal maintenance, old or damaged mitochondria need to be degraded, while the functional mitochondrial pool needs to be replenished with freshly synthesized components. Mitochondrial biogenesis is known to be primarily regulated via the PGC-1α-NRF1/2-TFAM pathway at the transcriptional level. However, while transcriptional regulation of mitochondrial genes can change the global mitochondrial content in neurons, it does not explain how a morphologically complex cell such as a neuron adapts to local differences in mitochondrial demand. In this review, we discuss regulatory mechanisms controlling mitochondrial biogenesis thereby making a case for differential regulation at the transcriptional and translational level. In neurons, additional regulation can occur due to the axonal localization of mRNAs encoding mitochondrial proteins. Hitchhiking of mRNAs on organelles including mitochondria as well as contact site formation between mitochondria and endolysosomes are required for local mitochondrial biogenesis in axons linking defects in any of these organelles to the mitochondrial dysfunction seen in various neurological disorders.
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Affiliation(s)
- Jara Tabitha Hees
- TUM Medical Graduate Center, Technical University of Munich, 81675 Munich, Germany
- Max Planck Institute for Biological Intelligence, in Foundation, 82152 Planegg-Martinsried, Germany
| | - Angelika Bettina Harbauer
- Max Planck Institute for Biological Intelligence, in Foundation, 82152 Planegg-Martinsried, Germany
- Institute of Neuronal Cell Biology, Technical University of Munich, 80802 Munich, Germany
- Munich Cluster for Systems Neurology, 81377 Munich, Germany
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4
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Cohen B, Altman T, Golani-Armon A, Savulescu AF, Ibraheem A, Mhlanga MM, Perlson E, Arava YS. The nuclear encoded Cox7c mRNA co-transport with mitochondria along axons via coding-region dependent mechanism. J Cell Sci 2022; 135:276008. [PMID: 35833493 PMCID: PMC9481926 DOI: 10.1242/jcs.259436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 07/07/2022] [Indexed: 11/20/2022] Open
Abstract
Nuclear-encoded mitochondrial protein mRNAs have been found to be localized and locally translated within neuronal processes. However, the mechanism of transport for those mRNAs to distal locations is not fully understood. Here, we describe axonal co-transport of Cox7c with mitochondria. Fractionation analysis and single-molecule fluorescence in situ hybridization (smFISH) assay revealed that endogenous mRNA encoding Cox7c was preferentially associated with mitochondria in a mouse neuronal cell line and within mouse primary motor neuron axons, whereas other mRNAs that do not encode mitochondrial protein were much less associated. Live-cell imaging of MS2-tagged Cox7c mRNA further confirmed the preferential colocalization and co-transport of Cox7c mRNA with mitochondria in motor neuron axons. Intriguingly, the coding region, rather than the 3′ untranslated region (UTR), was the key domain for the co-transport. Our results reveal that Cox7c mRNA can be transported with mitochondria along significant distances and that its coding region is a major recognition feature. This is consistent with the idea that mitochondria can play a vital role in spatial regulation of the axonal transcriptome at distant neuronal sites. Summary: Biochemical and live imaging analyses show that in mouse axons, Cox7c mRNA is associated and transported with mitochondria. Mutational analysis identifies mRNA domains essential for co-transport.
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Affiliation(s)
- Bar Cohen
- Faculty of Biology, Technion - Israel Institute of Technology, Israel
| | - Topaz Altman
- Sackler Faculty of Medicine, Tel Aviv University, Israel
| | - Adi Golani-Armon
- Faculty of Biology, Technion - Israel Institute of Technology, Israel.,Faculty of Nanosciences and Nanoengineering, Technion - Israel Institute of Technology, Israel
| | - Anca F Savulescu
- Division of Chemical, Systems & Synthetic Biology, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, Institute of Infectious Disease & Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Amjd Ibraheem
- Sackler Faculty of Medicine, Tel Aviv University, Israel
| | - Musa M Mhlanga
- Radboud Institute for Molecular Life Sciences (RIMLS), Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands.,Epigenomics & Single Cell Biophysics Group, Department of Cell Biology, FNWI, Radboud University, 6525 GA Nijmegen, the Netherlands.,Department of Human Genetics, Radboud University Medical Center, 6525 GA Nijmegen, the Netherlands
| | - Eran Perlson
- Sackler Faculty of Medicine, Tel Aviv University, Israel
| | - Yoav S Arava
- Faculty of Biology, Technion - Israel Institute of Technology, Israel
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5
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Heroin Addiction Induces Axonal Transport Dysfunction in the Brain Detected by In Vivo MRI. Neurotox Res 2022; 40:1070-1085. [PMID: 35759084 DOI: 10.1007/s12640-022-00533-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 06/13/2022] [Accepted: 06/13/2022] [Indexed: 10/17/2022]
Abstract
Heroin is a highly addictive drug that causes axonal damage. Here, manganese-enhanced magnetic resonance imaging (MEMRI) was used to dynamically monitor axonal transport at different stages of heroin addiction. Rat models of heroin addiction (HA) and prolonged heroin addiction (PHA) were established by injecting rats with heroin at different stages. Heroin-induced learning and memory deficits were evaluated in the Morris water maze (MWM), and MEMRI was used to dynamically evaluate axonal transport in the olfactory pathway. The expression of proteins related to axonal structure and function was also assessed by Western blotting. Transmission electron microscopy (TEM) was used to observe ultrastructural changes, and protein levels of neurofilament heavy chain (NF-H) were analyzed by immunofluorescence staining. HA rats, especially PHA rats, exhibited worse spatial learning and memory than control rats. Compared with HA rats and control rats, PHA rats exhibited significantly longer escape latencies, significantly fewer platform-location crossings, and significantly more time in the target quadrant during the MWM test. Mn2+ transport was accelerated in HA rats. PHA rats exhibited severely reduced Mn2+ transport, and the axonal transport rate (ATR) was significantly lower in these rats than in control rats (P < 0.001). The levels of cytoplasmic dynein and kinesin-1 were significantly decreased in the PHA group than in the control group (P < 0.001); additionally, the levels of energy-related proteins, including cytochrome c oxidase (COX) IV and ATP synthase subunit beta (ATPB), were lower in the PHA group (P < 0.001). The brains of heroin-exposed rats displayed an abnormal ultrastructure, with neuronal apoptosis and mitochondrial dysfunction. Heroin exposure decreased the expression of NF-H, as indicated by significantly reduced staining intensities in tissues from HA and PHA rats (P < 0.05). MEMRI detected axonal transport dysfunction caused by long-term repeated exposure to heroin. The main causes of axonal transport impairment may be decreases in the levels of motor proteins and mitochondrial dysfunction. This study shows that MEMRI is a potential tool for visualizing axonal transport in individuals with drug addictions, providing a new way to evaluate addictive encephalopathy.
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6
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mtIF3 is locally translated in axons and regulates mitochondrial translation for axonal growth. BMC Biol 2022; 20:12. [PMID: 34996455 PMCID: PMC8742369 DOI: 10.1186/s12915-021-01215-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 11/09/2021] [Indexed: 11/13/2022] Open
Abstract
Background The establishment and maintenance of functional neural connections relies on appropriate distribution and localization of mitochondria in neurites, as these organelles provide essential energy and metabolites. In particular, mitochondria are transported to axons and support local energy production to maintain energy-demanding neuronal processes including axon branching, growth, and regeneration. Additionally, local protein synthesis is required for structural and functional changes in axons, with nuclear-encoded mitochondrial mRNAs having been found localized in axons. However, it remains unclear whether these mRNAs are locally translated and whether the potential translated mitochondrial proteins are involved in the regulation of mitochondrial functions in axons. Here, we aim to further understand the purpose of such compartmentalization by focusing on the role of mitochondrial initiation factor 3 (mtIF3), whose nuclear-encoded transcripts have been shown to be present in axonal growth cones. Results We demonstrate that brain-derived neurotrophic factor (BDNF) induces local translation of mtIF3 mRNA in axonal growth cones. Subsequently, mtIF3 protein is translocated into axonal mitochondria and promotes mitochondrial translation as assessed by our newly developed bimolecular fluorescence complementation sensor for the assembly of mitochondrial ribosomes. We further show that BDNF-induced axonal growth requires mtIF3-dependent mitochondrial translation in distal axons. Conclusion We describe a previously unknown function of mitochondrial initiation factor 3 (mtIF3) in axonal protein synthesis and development. These findings provide insight into the way neurons adaptively control mitochondrial physiology and axonal development via local mtIF3 translation. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01215-w.
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7
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Perrone-Capano C, Volpicelli F, Penna E, Chun JT, Crispino M. Presynaptic protein synthesis and brain plasticity: From physiology to neuropathology. Prog Neurobiol 2021; 202:102051. [PMID: 33845165 DOI: 10.1016/j.pneurobio.2021.102051] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 03/14/2021] [Accepted: 04/07/2021] [Indexed: 12/12/2022]
Abstract
To form and maintain extremely intricate and functional neural circuitry, mammalian neurons are typically endowed with highly arborized dendrites and a long axon. The synapses that link neurons to neurons or to other cells are numerous and often too remote for the cell body to make and deliver new proteins to the right place in time. Moreover, synapses undergo continuous activity-dependent changes in their number and strength, establishing the basis of neural plasticity. The innate dilemma is then how a highly complex neuron provides new proteins for its cytoplasmic periphery and individual synapses to support synaptic plasticity. Here, we review a growing body of evidence that local protein synthesis in discrete sites of the axon and presynaptic terminals plays crucial roles in synaptic plasticity, and that deregulation of this local translation system is implicated in various pathologies of the nervous system.
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Affiliation(s)
- Carla Perrone-Capano
- Department of Pharmacy, University of Naples Federico II, Naples, Italy; Institute of Genetics and Biophysics "Adriano Buzzati Traverso", CNR, Naples, Italy.
| | | | - Eduardo Penna
- Department of Biology, University of Naples Federico II, Naples, Italy.
| | - Jong Tai Chun
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy.
| | - Marianna Crispino
- Department of Biology, University of Naples Federico II, Naples, Italy.
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8
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Dalla Costa I, Buchanan CN, Zdradzinski MD, Sahoo PK, Smith TP, Thames E, Kar AN, Twiss JL. The functional organization of axonal mRNA transport and translation. Nat Rev Neurosci 2021; 22:77-91. [PMID: 33288912 PMCID: PMC8161363 DOI: 10.1038/s41583-020-00407-7] [Citation(s) in RCA: 86] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2020] [Indexed: 12/13/2022]
Abstract
Axons extend for tremendously long distances from the neuronal soma and make use of localized mRNA translation to rapidly respond to different extracellular stimuli and physiological states. The locally synthesized proteins support many different functions in both developing and mature axons, raising questions about the mechanisms by which local translation is organized to ensure the appropriate responses to specific stimuli. Publications over the past few years have uncovered new mechanisms for regulating the axonal transport and localized translation of mRNAs, with several of these pathways converging on the regulation of cohorts of functionally related mRNAs - known as RNA regulons - that drive axon growth, axon guidance, injury responses, axon survival and even axonal mitochondrial function. Recent advances point to these different regulatory pathways as organizing platforms that allow the axon's proteome to be modulated to meet its physiological needs.
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Affiliation(s)
- Irene Dalla Costa
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Courtney N Buchanan
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | | | - Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Terika P Smith
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Elizabeth Thames
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA.
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9
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Turner-Bridger B, Caterino C, Cioni JM. Molecular mechanisms behind mRNA localization in axons. Open Biol 2020; 10:200177. [PMID: 32961072 PMCID: PMC7536069 DOI: 10.1098/rsob.200177] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/01/2020] [Indexed: 12/12/2022] Open
Abstract
Messenger RNA (mRNA) localization allows spatiotemporal regulation of the proteome at the subcellular level. This is observed in the axons of neurons, where mRNA localization is involved in regulating neuronal development and function by orchestrating rapid adaptive responses to extracellular cues and the maintenance of axonal homeostasis through local translation. Here, we provide an overview of the key findings that have broadened our knowledge regarding how specific mRNAs are trafficked and localize to axons. In particular, we review transcriptomic studies investigating mRNA content in axons and the molecular principles underpinning how these mRNAs arrived there, including cis-acting mRNA sequences and trans-acting proteins playing a role. Further, we discuss evidence that links defective axonal mRNA localization and pathological outcomes.
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Affiliation(s)
- Benita Turner-Bridger
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, UK
| | - Cinzia Caterino
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy
| | - Jean-Michel Cioni
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy
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10
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Gamarra M, Blanco-Urrejola M, Batista AFR, Imaz J, Baleriola J. Object-Based Analyses in FIJI/ImageJ to Measure Local RNA Translation Sites in Neurites in Response to Aβ1-42 Oligomers. Front Neurosci 2020; 14:547. [PMID: 32581689 PMCID: PMC7284234 DOI: 10.3389/fnins.2020.00547] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 05/04/2020] [Indexed: 12/19/2022] Open
Abstract
Subcellular protein delivery is especially important in signal transduction and cell behavior, and is typically achieved by localization signals within the protein. However, protein delivery can also rely on localization of mRNAs that are translated at target sites. Although once considered heretical, RNA localization has proven to be highly conserved in eukaryotes. RNA localization and localized translation are especially relevant in polarized cells like neurons where neurites extend dozens to hundreds of centimeters away from the soma. Local translation confers dendrites and axons the capacity to respond to their environment in an acute manner without fully relying on somatic signals. The relevance of local protein synthesis in neuron development, maintenance and disease has not been fully acknowledged until recent years, partly due to the limited amount of locally produced proteins. For instance, in hippocampal neurons levels of newly synthesized somatic proteins can be more than 20–30 times greater than translation levels of neuritic proteins. Thus local translation events can be easily overlooked under the microscope. Here we describe an object-based analysis used to visualize and quantify local RNA translation sites in neurites. Newly synthesized proteins are tagged with puromycin and endogenous RNAs labeled with SYTO. After imaging, signals corresponding to neuritic RNAs and proteins are filtered with a Laplacian operator to enhance the edges. Resulting pixels are converted into objects and selected by automatic masking followed by signal smoothing. Objects corresponding to RNA or protein and colocalized objects (RNA and protein) are quantified along individual neurites. Colocalization between RNA and protein in neurites correspond to newly synthesized proteins arising from localized RNAs and represent localized translation sites. To test the validity of our analyses we have compared control neurons to Aβ1–42-treated neurons. Aβ is involved in the pathology of Alzheimer’s disease and was previously reported to induce local translation in axons and dendrites which in turn contributes to the disease. We have observed that Aβ increases the synthesis of neuritic proteins as well as the fraction of translating RNAs in distal sites of the neurite, suggesting an induction of local protein synthesis. Our results thus confirm previous reports and validate our quantification method.
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Affiliation(s)
- María Gamarra
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country, Bilbao, Spain
| | - Maite Blanco-Urrejola
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country, Bilbao, Spain.,Department of Cell Biology and Histology, Faculty of Medicine and Nursing, University of the Basque Country, Leioa, Spain
| | - Andreia F R Batista
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Life and Health Sciences Research Institute, School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's, PT Associate Laboratory, Universidade do Minho, Guimarães, Portugal
| | - Josune Imaz
- Department of Neurosciences, Faculty of Medicine and Nursing, University of the Basque Country, Bilbao, Spain
| | - Jimena Baleriola
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Department of Cell Biology and Histology, Faculty of Medicine and Nursing, University of the Basque Country, Leioa, Spain.,IKERBASQUE Basque Foundation for Science, Bilbao, Spain
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11
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Kodavati M, Wang H, Hegde ML. Altered Mitochondrial Dynamics in Motor Neuron Disease: An Emerging Perspective. Cells 2020; 9:cells9041065. [PMID: 32344665 PMCID: PMC7226538 DOI: 10.3390/cells9041065] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 04/15/2020] [Accepted: 04/21/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondria plays privotal role in diverse pathways that regulate cellular function and survival, and have emerged as a prime focus in aging and age-associated motor neuron diseases (MNDs), such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Accumulating evidence suggests that many amyloidogenic proteins, including MND-associated RNA/DNA-binding proteins fused in sarcoma (FUS) and TAR DNA binding protein (TDP)-43, are strongly linked to mitochondrial dysfunction. Animal model and patient studies have highlighted changes in mitochondrial structure, plasticity, replication/copy number, mitochondrial DNA instability, and altered membrane potential in several subsets of MNDs, and these observations are consistent with the evidence of increased excitotoxicity, induction of reactive oxygen species, and activation of intrinsic apoptotic pathways. Studies in MND rodent models also indicate that mitochondrial abnormalities begin prior to the clinical and pathological onset of the disease, suggesting a causal role of mitochondrial dysfunction. Our recent studies, which demonstrated the involvement of specific defects in DNA break-ligation mediated by DNA ligase 3 (LIG3) in FUS-associated ALS, raised a key question of its potential implication in mitochondrial DNA transactions because LIG3 is essential for both mitochondrial DNA replication and repair. This question, as well as how wild-type and mutant MND-associated factors affect mitochondria, remain to be elucidated. These new investigation avenues into the mechanistic role of mitochondrial dysfunction in MNDs are critical to identify therapeutic targets to alleviate mitochondrial toxicity and its consequences. In this article, we critically review recent advances in our understanding of mitochondrial dysfunction in diverse subgroups of MNDs and discuss challenges and future directions.
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Affiliation(s)
- Manohar Kodavati
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX 77030, USA; (M.K.); (H.W.)
| | - Haibo Wang
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX 77030, USA; (M.K.); (H.W.)
| | - Muralidhar L. Hegde
- Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX 77030, USA; (M.K.); (H.W.)
- Department of Neurosurgery, Weill Medical College, New York, NY 10065, USA
- Correspondence:
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12
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Mechanisms Linking Mitochondrial Dysfunction and Proteostasis Failure. Trends Cell Biol 2020; 30:317-328. [PMID: 32200806 DOI: 10.1016/j.tcb.2020.01.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/16/2020] [Accepted: 01/17/2020] [Indexed: 12/19/2022]
Abstract
Maintaining cellular protein homeostasis (proteostasis) is an essential task for all eukaryotes. Proteostasis failure worsens with aging and is considered a cause of and a therapeutic target for age-related diseases including neurodegenerative disorders. The cellular networks regulating proteostasis and the pathogenic events driving proteostasis failure in disease remain poorly understood. Model organism studies in yeast and Drosophila reveal an intriguing link between mitochondrial function and proteostasis. In this review we examine recent findings on mitochondrial outer membrane (MOM)-associated mRNA translation, how this process is sensitive to mitochondrial dysfunction and constantly surveyed by ribosome-associated quality control (RQC), and how defects in this process generate aberrant proteins with unusual C-terminal extensions (CTEs) that promote aggregation and drive proteostasis failure. We also discuss the implications for human diseases.
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13
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Pushpalatha KV, Besse F. Local Translation in Axons: When Membraneless RNP Granules Meet Membrane-Bound Organelles. Front Mol Biosci 2019; 6:129. [PMID: 31824961 PMCID: PMC6882739 DOI: 10.3389/fmolb.2019.00129] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 11/06/2019] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic cell compartmentalization relies on long-known membrane-delimited organelles, as well as on more recently discovered membraneless macromolecular condensates. How these two types of organelles interact to regulate cellular functions is still largely unclear. In this review, we highlight how membraneless ribonucleoprotein (RNP) organelles, enriched in RNAs and associated regulatory proteins, cooperate with membrane-bound organelles for tight spatio-temporal control of gene expression in the axons of neuronal cells. Specifically, we present recent evidence that motile membrane-bound organelles are used as vehicles by RNP cargoes, promoting the long-range transport of mRNA molecules to distal axons. As demonstrated by recent work, membrane-bound organelles also promote local protein synthesis, by serving as platforms for the local translation of mRNAs recruited to their outer surface. Furthermore, dynamic and specific association between RNP cargoes and membrane-bound organelles is mediated by bi-partite adapter molecules that interact with both types of organelles selectively, in a regulated-manner. Maintaining such a dynamic interplay is critical, as alterations in this process are linked to neurodegenerative diseases. Together, emerging studies thus point to the coordination of membrane-bound and membraneless organelles as an organizing principle underlying local cellular responses.
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Affiliation(s)
| | - Florence Besse
- Université Côte d'Azur, CNRS, Inserm, Institut de Biology Valrose, Nice, France
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14
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Martínez JC, Randolph LK, Iascone DM, Pernice HF, Polleux F, Hengst U. Pum2 Shapes the Transcriptome in Developing Axons through Retention of Target mRNAs in the Cell Body. Neuron 2019; 104:931-946.e5. [PMID: 31606248 DOI: 10.1016/j.neuron.2019.08.035] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 05/31/2019] [Accepted: 08/21/2019] [Indexed: 02/07/2023]
Abstract
Localized protein synthesis is fundamental for neuronal development, maintenance, and function. Transcriptomes in axons and soma are distinct, but the mechanisms governing the composition of axonal transcriptomes and their developmental regulation are only partially understood. We found that the binding motif for the RNA-binding proteins Pumilio 1 and 2 (Pum1 and Pum2) is underrepresented in transcriptomes of developing axons. Introduction of Pumilio-binding elements (PBEs) into mRNAs containing a β-actin zipcode prevented axonal localization and translation. Pum2 is restricted to the soma of developing neurons, and Pum2 knockdown or blocking its binding to mRNA caused the appearance and translation of PBE-containing mRNAs in axons. Pum2-deficient neurons exhibited axonal growth and branching defects in vivo and impaired axon regeneration in vitro. These results reveal that Pum2 shapes axonal transcriptomes by preventing the transport of PBE-containing mRNAs into axons, and they identify somatic mRNAs retention as a mechanism for the temporal control of intra-axonal protein synthesis.
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Affiliation(s)
- José C Martínez
- Medical Scientist Training Program, Columbia University Irving Medical Center, New York, NY 10032, USA; The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Lisa K Randolph
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Doctoral Program in Neurobiology and Behavior, Columbia University, New York, NY 10027, USA
| | - Daniel Maxim Iascone
- Doctoral Program in Neurobiology and Behavior, Columbia University, New York, NY 10027, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Helena F Pernice
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Anatomy and Cell Biology, Biomedical Center, Medical Faculty, Ludwig Maximilians University, 82152 Planegg-Martinsried, Germany
| | - Franck Polleux
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Neuroscience, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10027, USA; Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Ulrich Hengst
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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15
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Aschrafi A, Berndt A, Kowalak JA, Gale JR, Gioio AE, Kaplan BB. Angiotensin II mediates the axonal trafficking of tyrosine hydroxylase and dopamine β-hydroxylase mRNAs and enhances norepinephrine synthesis in primary sympathetic neurons. J Neurochem 2019; 150:666-677. [PMID: 31306490 PMCID: PMC7164330 DOI: 10.1111/jnc.14821] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2019] [Revised: 06/22/2019] [Accepted: 07/02/2019] [Indexed: 12/13/2022]
Abstract
In the sympatho-adrenal system, angiotensin II (Ang II) acts as a key neuromodulatory component. At sympathetic nerve terminals, Ang II influences sympathetic transmission by enhancing norepinephrine (NE) synthesis, facilitating NE release and inhibiting NE uptake. Previously, it was demonstrated that tyrosine hydroxylase (TH) mRNA is trafficked to the distal axons of primary superior cervical ganglia (SCG) neurons, directed by a cis-acting regulatory element (i.e. zipcode) located in the 3'UTR of the transcript. Results of metabolic labeling studies established that the mRNA is locally translated. It was further shown that the axonal trafficking of the mRNA encoding the enzyme plays an important role in mediating dopamine (DA) and NE synthesis and may facilitate the maintenance of axonal catecholamine levels. In the present study, the hypothesis was tested that Ang II induces NE synthesis in rat primary SCG neurons via the modulation of the trafficking of the mRNAs encoding the catecholamine synthesizing enzymes TH and dopamine β-hydroxylase (DBH). Treatment of SCG neurons with the Ang II receptor type 1 (AT1R) agonist, L-162,313, increases the axonal levels of TH and DBH mRNA and protein and results in elevated NE levels. Conversely, treatment of rat SCG neurons with the AT1R antagonist, Eprosartan, abolished the L-162,313-mediated increase in axonal levels of TH and DBH mRNA and protein. In a first attempt to identify the proteins involved in the Ang II-mediated axonal transport of TH mRNA, we used a biotinylated 50-nucleotide TH RNA zipcode as bait in the affinity purification of TH zipcode-associated proteins. Mass spectrometric analysis of the TH zipcode ribonucleoprotein (RNP) complex immune-purified from SCG neurons led to the identification of 163 somal and 127 axonal proteins functionally involved in binding nucleic acids, the translational machinery or acting as subunits of cytoskeletal and motor proteins. Surprisingly, immune-purification of the TH axonal trafficking complex, results in the acquisition of DBH mRNA, suggesting that these mRNAs maybe transported to the axon together, possibly in the same RNP complex. Taken together, our results point to a novel mechanism by which Ang II participates in the regulation of axonal synthesis of NE by modulating the local trafficking and expression of TH and DBH, two key enzymes involved in the catecholamine biosynthetic pathway.
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Affiliation(s)
| | | | | | - Jenna R Gale
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anthony E Gioio
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Barry B Kaplan
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
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16
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Farias J, Sotelo JR, Sotelo‐Silveira J. Toward Axonal System Biology: Genome Wide Views of Local mRNA Translation. Proteomics 2019; 19:e1900054. [DOI: 10.1002/pmic.201900054] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/12/2019] [Indexed: 11/10/2022]
Affiliation(s)
- Joaquina Farias
- Departamento de Proteínas y Ácidos NucleicosInstituto de Investigaciones Biológicas Clemente Estable Montevideo CP 11600 Uruguay
- Departamento de GenómicaInstituto de Investigaciones Biológicas Clemente Estable Montevideo CP 11600 Uruguay
| | - José Roberto Sotelo
- Departamento de Proteínas y Ácidos NucleicosInstituto de Investigaciones Biológicas Clemente Estable Montevideo CP 11600 Uruguay
| | - José Sotelo‐Silveira
- Departamento de GenómicaInstituto de Investigaciones Biológicas Clemente Estable Montevideo CP 11600 Uruguay
- Sección Biología CelularFacultad de Ciencias, Universidad de la República Montevideo CP 11400 Uruguay
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17
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Harrison BJ, Park JW, Gomes C, Petruska JC, Sapio MR, Iadarola MJ, Chariker JH, Rouchka EC. Detection of Differentially Expressed Cleavage Site Intervals Within 3' Untranslated Regions Using CSI-UTR Reveals Regulated Interaction Motifs. Front Genet 2019; 10:182. [PMID: 30915105 PMCID: PMC6422928 DOI: 10.3389/fgene.2019.00182] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 02/19/2019] [Indexed: 01/08/2023] Open
Abstract
The length of untranslated regions at the 3' end of transcripts (3'UTRs) is regulated by alternate polyadenylation (APA). 3'UTRs contain regions that harbor binding motifs for regulatory molecules. However, the mechanisms that coordinate the 3'UTR length of specific groups of transcripts are not well-understood. We therefore developed a method, CSI-UTR, that models 3'UTR structure as tandem segments between functional alternative-polyadenylation sites (termed cleavage site intervals-CSIs). This approach facilitated (1) profiling of 3'UTR isoform expression changes and (2) statistical enrichment of putative regulatory motifs. CSI-UTR analysis is UTR-annotation independent and can interrogate legacy data generated from standard RNA-Seq libraries. CSI-UTR identified a set of CSIs in human and rodent transcriptomes. Analysis of RNA-Seq datasets from neural tissue identified differential expression events within 3'UTRs not detected by standard gene-based differential expression analyses. Further, in many instances 3'UTR and CDS from the same gene were regulated differently. This modulation of motifs for RNA-interacting molecules with potential condition-dependent and tissue-specific RNA binding partners near the polyA signal and CSI junction may play a mechanistic role in the specificity of alternative polyadenylation. Source code, CSI BED files and example datasets are available at: https://github.com/UofLBioinformatics/CSI-UTR.
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Affiliation(s)
- Benjamin J Harrison
- Department of Biomedical Sciences, Center for Excellence in the Neurosciences, College of Osteopathic Medicine, University of New England, Biddeford, ME, United States.,Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY, United States.,Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, Louisville, KY, United States
| | - Juw Won Park
- Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, Louisville, KY, United States.,Department of Computer Engineering and Computer Science, Speed School of Engineering, University of Louisville, Louisville, KY, United States
| | - Cynthia Gomes
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY, United States
| | - Jeffrey C Petruska
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY, United States.,Kentucky Spinal Cord Injury Research Center, University of Louisville, Louisville, KY, United States.,Department of Neurological Surgery, University of Louisville, Louisville, KY, United States
| | - Matthew R Sapio
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Michael J Iadarola
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, United States
| | - Julia H Chariker
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY, United States.,Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, Louisville, KY, United States
| | - Eric C Rouchka
- Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, Louisville, KY, United States.,Department of Computer Engineering and Computer Science, Speed School of Engineering, University of Louisville, Louisville, KY, United States
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18
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Aganzo M, Montojo MT, López de Las Hazas MC, Martínez-Descals A, Ricote-Vila M, Sanz R, González-Peralta I, Martín-Hernández R, de Dios O, Garcés C, Galdón A, Lorenzo Ó, Tomás-Zapico C, Dávalos A, Vázquez C, González N. Customized Dietary Intervention Avoids Unintentional Weight Loss and Modulates Circulating miRNAs Footprint in Huntington's Disease. Mol Nutr Food Res 2018; 62:e1800619. [PMID: 30359470 DOI: 10.1002/mnfr.201800619] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 10/02/2018] [Indexed: 12/25/2022]
Abstract
SCOPE Huntington's disease (HD) is a rare progressive neurodegenerative disorder of genetic origin, with no definitive treatment. Unintentional weight loss (UWL) is a clinical feature of symptomatic HD subjects. To prevent UWL, a customized HD diet is designed and its impact on plasma miRNA HD footprint and neurological parameters is examined. METHODS AND RESULTS Eleven participants are included, BMI ≤ 18 kg m-2 or UWL of 5% in 6 months or 10% in a year. Diet design is based on nutritional surveys and interviews of participants and caregivers and on published literature review. Twelve-month dietary intervention, with follow-up every 3 months, induces high diet adherence, which manages to curb UWL in all participants (73% gained weight). Noticeable increases in fat mass and leptin levels are obtained. The results also show significant decrease in the expression of 19 miRNAs, which are previously reported to be upregulated in HD-patients versus healthy controls: revealing hsa-miR-338-3p, hsa-miR-128-3p, hsa-miR-23a-3p, and hsa-miR-24-3p as potential HD-biomarkers. The diminished expression of hsa-miR-100-5p reflects the general maintenance of the functional status. Cognitive status is improved in six of 11 participants, while only three present better motor-score values. CONCLUSION A customized HD-diet prevents UWL and modified miRNAs HD-footprint. The normalization of miRNA values suggests its potentially use as HD-biomarkers.
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Affiliation(s)
- Miguel Aganzo
- Division of Endocrinology, Fundación Jiménez Díaz, 28040, Madrid, Spain
| | - María-Teresa Montojo
- Department of Neurology, Movement Disorders Unit, Fundación Jiménez Díaz, 28040, Madrid, Spain
| | - María-Carmen López de Las Hazas
- Laboratory of Epigenetics of Lipid Metabolism, Instituto Madrileño de Estudios Avanzados (IMDEA)-Alimentación, CEI UAM+CSIC, Madrid, Spain
| | | | - Marta Ricote-Vila
- Renal, Vascular and Diabetes Research Laboratory, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz (IIS-FJD), UAM, Madrid, Spain
| | - Raúl Sanz
- Centros de Estudios Genéticcos ATG Medical, Madrid, Spain
| | - Irene González-Peralta
- Centros de Estudios Genéticcos ATG Medical, Madrid, Spain.,Escuela Superior de Ciencias Experimentales y Tecnología. URJC, Madrid, Spain
| | - Roberto Martín-Hernández
- Laboratory of Epigenetics of Lipid Metabolism, Instituto Madrileño de Estudios Avanzados (IMDEA)-Alimentación, CEI UAM+CSIC, Madrid, Spain
| | | | | | - Alba Galdón
- Division of Endocrinology, Fundación Jiménez Díaz, 28040, Madrid, Spain
| | - Óscar Lorenzo
- Renal, Vascular and Diabetes Research Laboratory, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz (IIS-FJD), UAM, Madrid, Spain
| | - Cristina Tomás-Zapico
- Department of Functional Biology, Physiology Area, Faculty of Medicine, University of Oviedo, Oviedo, Spain
| | - Alberto Dávalos
- Laboratory of Epigenetics of Lipid Metabolism, Instituto Madrileño de Estudios Avanzados (IMDEA)-Alimentación, CEI UAM+CSIC, Madrid, Spain
| | - Clotilde Vázquez
- Division of Endocrinology, Fundación Jiménez Díaz, 28040, Madrid, Spain
| | - Nieves González
- Renal, Vascular and Diabetes Research Laboratory, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz (IIS-FJD), UAM, Madrid, Spain.,Centros de Estudios Genéticcos ATG Medical, Madrid, Spain.,Spanish Biomedical Research Network in Diabetes and Associated Metabolic Disorders (CIBERDEM), Madrid, Spain
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19
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Sahoo PK, Smith DS, Perrone-Bizzozero N, Twiss JL. Axonal mRNA transport and translation at a glance. J Cell Sci 2018; 131:jcs196808. [PMID: 29654160 PMCID: PMC6518334 DOI: 10.1242/jcs.196808] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Localization and translation of mRNAs within different subcellular domains provides an important mechanism to spatially and temporally introduce new proteins in polarized cells. Neurons make use of this localized protein synthesis during initial growth, regeneration and functional maintenance of their axons. Although the first evidence for protein synthesis in axons dates back to 1960s, improved methodologies, including the ability to isolate axons to purity, highly sensitive RNA detection methods and imaging approaches, have shed new light on the complexity of the transcriptome of the axon and how it is regulated. Moreover, these efforts are now uncovering new roles for locally synthesized proteins in neurological diseases and injury responses. In this Cell Science at a Glance article and the accompanying poster, we provide an overview of how axonal mRNA transport and translation are regulated, and discuss their emerging links to neurological disorders and neural repair.
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Affiliation(s)
- Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, 715 Sumter St., CLS 401, Columbia, SC 29208, USA
| | - Deanna S Smith
- Department of Biological Sciences, University of South Carolina, 715 Sumter St., CLS 401, Columbia, SC 29208, USA
| | - Nora Perrone-Bizzozero
- Department of Neurosciences, University of New Mexico School of Medicine, 1 University of New Mexico, MSC08 4740, Albuquerque, NM 87131, USA
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, 715 Sumter St., CLS 401, Columbia, SC 29208, USA
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20
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Tóth EN, Lohith A, Mondal M, Guo J, Fukamizu A, Pourmand N. Single-cell nanobiopsy reveals compartmentalization of mRNAs within neuronal cells. J Biol Chem 2018; 293:4940-4951. [PMID: 29378846 DOI: 10.1074/jbc.m117.800763] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 01/21/2018] [Indexed: 12/22/2022] Open
Abstract
In highly polarized cells such as neurons, compartmentalization of mRNA and of local protein synthesis enables remarkably fast, precise, and local responses to external stimuli. These responses are highly important for neuron growth cone guidance, synapse formation, and regeneration following injury. Because an altered spatial distribution of mRNA can result in mental retardation or neurodegenerative diseases, subcellular transcriptome analysis of neurons could be a useful tool for studying these conditions, but current techniques, such as in situ hybridization, bulk microarray, and RNA-Seq, impose tradeoffs between spatial resolution and multiplexing. To obtain a comprehensive analysis of the cell body versus neurite transcriptome from the same neuron, we have recently developed a label-free, single-cell nanobiopsy platform based on scanning ion conductance microscopy that uses electrowetting within a quartz nanopipette to extract cellular material from living cells with minimal disruption of the cellular membrane and milieu. In this study, we used this platform to collect samples from the cell bodies and neurites of human neurons and analyzed the mRNA pool with multiplex RNA sequencing. The minute volume of a nanobiopsy sample allowed us to extract samples from several locations in the same cell and to map the various mRNA species to specific subcellular locations. In addition to previously identified transcripts, we discovered new sets of mRNAs localizing to neurites, including nuclear genes such as Eomes and Hmgb3 In summary, our single-neuron nanobiopsy analysis provides opportunities to improve our understanding of intracellular mRNA transport and local protein composition in neuronal growth, connectivity, and function.
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Affiliation(s)
- Eszter N Tóth
- Ph.D. Program in Human Biology, School of Integrative and Global Majors, Ibaraki 305-8577, Japan; Life Science Center, Tsukuba Advanced Research Alliance, Department of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8577, Japan; Department of Biomolecular Engineering, Jack Baskin School of Engineering, University of California at Santa Cruz, Santa Cruz, California 95064
| | - Akshar Lohith
- Department of Biomolecular Engineering, Jack Baskin School of Engineering, University of California at Santa Cruz, Santa Cruz, California 95064
| | - Manas Mondal
- Department of Chemistry and Biochemistry & Biodesign Institute, Arizona State University, Tempe, Arizona 85287
| | - Jia Guo
- Department of Chemistry and Biochemistry & Biodesign Institute, Arizona State University, Tempe, Arizona 85287
| | - Akiyoshi Fukamizu
- Ph.D. Program in Human Biology, School of Integrative and Global Majors, Ibaraki 305-8577, Japan; Life Science Center, Tsukuba Advanced Research Alliance, Department of Life and Environmental Sciences, University of Tsukuba, Ibaraki 305-8577, Japan
| | - Nader Pourmand
- Department of Biomolecular Engineering, Jack Baskin School of Engineering, University of California at Santa Cruz, Santa Cruz, California 95064.
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21
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Van Driesche SJ, Martin KC. New frontiers in RNA transport and local translation in neurons. Dev Neurobiol 2018; 78:331-339. [DOI: 10.1002/dneu.22574] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 12/27/2017] [Accepted: 12/27/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Sarah J. Van Driesche
- Department of Biological Chemistry; University of California; Los Angeles California
| | - Kelsey C. Martin
- Department of Biological Chemistry; University of California; Los Angeles California
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22
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Costa CJ, Willis DE. To the end of the line: Axonal mRNA transport and local translation in health and neurodegenerative disease. Dev Neurobiol 2017; 78:209-220. [PMID: 29115051 DOI: 10.1002/dneu.22555] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/20/2017] [Accepted: 11/01/2017] [Indexed: 12/14/2022]
Abstract
Axons and growth cones, by their very nature far removed from the cell body, encounter unique environments and require distinct populations of proteins. It seems only natural, then, that they have developed mechanisms to locally synthesize a host of proteins required to perform their specialized functions. Acceptance of this ability has taken decades; however, there is now consensus that axons do indeed have the capacity for local translation, and that this capacity is even retained into adulthood. Accumulating evidence supports the role of locally synthesized proteins in the proper development, maintenance, and function of neurons, and newly emerging studies also suggest that disruption in this process has implications in a number of neurodevelopmental and neurodegenerative diseases. Here, we briefly review the long history of axonal mRNA localization and local translation, and the role that these locally synthesized proteins play in normal neuronal function. Additionally, we highlight the emerging evidence that dysregulation in these processes contributes to a wide range of pathophysiology, including neuropsychiatric disorders, Alzheimer's, and motor neuron diseases such as spinal muscular atrophy and Amyotrophic Lateral Sclerosis. © 2017 Wiley Periodicals, Inc. Develop. Neurobiol 78: 209-220, 2018.
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Affiliation(s)
| | - Dianna E Willis
- Burke Medical Research Institute, White Plains, New York, 10605.,Brain & Mind Research Institute, Weill Cornell Medicine, New York, New York
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23
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Kos A, Klein-Gunnewiek T, Meinhardt J, Loohuis NFMO, van Bokhoven H, Kaplan BB, Martens GJ, Kolk SM, Aschrafi A. MicroRNA-338 Attenuates Cortical Neuronal Outgrowth by Modulating the Expression of Axon Guidance Genes. Mol Neurobiol 2017; 54:3439-3452. [PMID: 27180071 PMCID: PMC5658782 DOI: 10.1007/s12035-016-9925-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/03/2016] [Indexed: 12/15/2022]
Abstract
MicroRNAs (miRs) are small non-coding RNAs that confer robustness to gene networks through post-transcriptional gene regulation. Previously, we identified miR-338 as a modulator of axonal outgrowth in sympathetic neurons. In the current study, we examined the role of miR-338 in the development of cortical neurons and uncovered its downstream mRNA targets. Long-term inhibition of miR-338 during neuronal differentiation resulted in reduced dendritic complexity and altered dendritic spine morphology. Furthermore, monitoring axon outgrowth in cortical cells revealed that miR-338 overexpression decreased, whereas inhibition of miR-338 increased axonal length. To identify gene targets mediating the observed phenotype, we inhibited miR-338 in cortical neurons and performed whole-transcriptome analysis. Pathway analysis revealed that miR-338 modulates a subset of transcripts involved in the axonal guidance machinery by means of direct and indirect gene targeting. Collectively, our results implicate miR-338 as a novel regulator of cortical neuronal maturation by fine-tuning the expression of gene networks governing cortical outgrowth.
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Affiliation(s)
- Aron Kos
- Department of Cognitive Neuroscience, Radboud university medical center, 6500 HB, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, 6525 AJ, Nijmegen, The Netherlands
| | - Teun Klein-Gunnewiek
- Department of Cognitive Neuroscience, Radboud university medical center, 6500 HB, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, 6525 AJ, Nijmegen, The Netherlands
| | - Julia Meinhardt
- Department of Cognitive Neuroscience, Radboud university medical center, 6500 HB, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, 6525 AJ, Nijmegen, The Netherlands
| | - Nikkie F M Olde Loohuis
- Department of Cognitive Neuroscience, Radboud university medical center, 6500 HB, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, 6525 AJ, Nijmegen, The Netherlands
| | - Hans van Bokhoven
- Department of Cognitive Neuroscience, Radboud university medical center, 6500 HB, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, 6525 AJ, Nijmegen, The Netherlands
- Department of Human Genetics, Radboud university medical center, 6500 HB, Nijmegen, The Netherlands
| | - Barry B Kaplan
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, 20892, USA
| | - Gerard J Martens
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, 6525 AJ, Nijmegen, The Netherlands
- Department of Molecular Animal Physiology, Radboud University, Nijmegen, The Netherlands
| | - Sharon M Kolk
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, 6525 AJ, Nijmegen, The Netherlands
- Department of Molecular Animal Physiology, Radboud University, Nijmegen, The Netherlands
| | - Armaz Aschrafi
- Donders Institute for Brain, Cognition, and Behaviour, Centre for Neuroscience, 6525 AJ, Nijmegen, The Netherlands.
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, 20892, USA.
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24
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Disruption of the Axonal Trafficking of Tyrosine Hydroxylase mRNA Impairs Catecholamine Biosynthesis in the Axons of Sympathetic Neurons. eNeuro 2017. [PMID: 28630892 PMCID: PMC5473686 DOI: 10.1523/eneuro.0385-16.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Tyrosine hydroxylase (TH) is the enzyme that catalyzes the rate-limiting step in the biosynthesis of the catecholamine neurotransmitters. In a previous communication, evidence was provided that TH mRNA is trafficked to the axon, where it is locally translated. In addition, a 50-bp sequence element in the 3'untranslated region (3'UTR) of TH mRNA was identified that directs TH mRNA to distal axons (i.e., zip-code). In the present study, the hypothesis was tested that local translation of TH plays an important role in the biosynthesis of the catecholamine neurotransmitters in the axon and/or presynaptic nerve terminal. Toward this end, a targeted deletion of the axonal transport sequence element was developed, using the lentiviral delivery of the CRISPR/Cas9 system, and two guide RNA (gRNA) sequences flanking the 50-bp cis-acting regulatory element in rat superior cervical ganglion (SCG) neurons. Deletion of the axonal transport element reduced TH mRNA levels in the distal axons and reduced the axonal protein levels of TH and TH activity as measured by phosphorylation of SER40 in SCG neurons. Moreover, deletion of the zip-code diminished the axonal levels of dopamine (DA) and norepinephrine (NE). Conversely, the local translation of exogenous TH mRNA in the distal axon enhanced TH levels and activity, and elevated axonal NE levels. Taken together, these results provide direct evidence to support the hypothesis that TH mRNA trafficking and local synthesis of TH play an important role in the synthesis of catecholamines in the axon and presynaptic terminal.
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25
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Hollis F, Kanellopoulos AK, Bagni C. Mitochondrial dysfunction in Autism Spectrum Disorder: clinical features and perspectives. Curr Opin Neurobiol 2017. [PMID: 28628841 DOI: 10.1016/j.conb.2017.05.018] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Autism Spectrum Disorder (ASD) is a prototypic pervasive developmental disorder characterized by social interaction, and communication deficits, repetitive, stereotypic patterns of behavior, and impairments in language and development. Clinical studies have identified mitochondrial disturbances at the levels of DNA, activity, complexes, oxidative stress, and metabolites in blood and urine of ASD patients. However, these observations from postmortem brains or peripheral tissues do not provide a direct link between autism and mitochondria. The synaptic abnormality of autistic patients has not been investigated yet. Here we review the findings of clinical studies investigating mitochondrial involvement in ASD patients, focusing particularly on the brain and the limitations and future directions needed in order to fully understand the role of mitochondria in ASD pathology.
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Affiliation(s)
- Fiona Hollis
- University of Lausanne, Department of Fundamental Neuroscience, Lausanne, Switzerland
| | | | - Claudia Bagni
- University of Lausanne, Department of Fundamental Neuroscience, Lausanne, Switzerland; University of Rome Tor Vergata, Department of Biomedicine and Prevention, Rome, Italy.
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Gale JR, Aschrafi A, Gioio AE, Kaplan BB. Nuclear-Encoded Mitochondrial mRNAs: A Powerful Force in Axonal Growth and Development. Neuroscientist 2017; 24:142-155. [PMID: 28614981 DOI: 10.1177/1073858417714225] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Axons, their growth cones, and synaptic nerve terminals are neuronal subcompartments that have high energetic needs. As such, they are enriched in mitochondria, which supply the ATP necessary to meet these demands. To date, a heterogeneous population of nuclear-encoded mitochondrial mRNAs has been identified in distal axons and growth cones. Accumulating evidence suggests that the local translation of these mRNAs is required for mitochondrial maintenance and axonal viability. Here, we review evidence that suggests a critical role for axonal translation of nuclear-encoded mitochondrial mRNAs in axonal growth and development. Additionally, we explore the role that site-specific translation at the mitochondria itself may play in this process. Finally, we briefly review the clinical implications of dysregulation of local translation of mitochondrial-related mRNAs in neurodevelopmental disorders.
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Affiliation(s)
- Jenna R Gale
- 1 Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Armaz Aschrafi
- 1 Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Anthony E Gioio
- 1 Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Barry B Kaplan
- 1 Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
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Kar AN, Lee SJ, Twiss JL. Expanding Axonal Transcriptome Brings New Functions for Axonally Synthesized Proteins in Health and Disease. Neuroscientist 2017; 24:111-129. [PMID: 28593814 DOI: 10.1177/1073858417712668] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intra-axonal protein synthesis has been shown to play critical roles in both development and repair of axons. Axons provide long-range connectivity in the nervous system, and disruption of their function and/or structure is seen in several neurological diseases and disorders. Axonally synthesized proteins or losses in axonally synthesized proteins contribute to neurodegenerative diseases, neuropathic pain, viral transport, and survival of axons. Increasing sensitivity of RNA detection and quantitation coupled with methods to isolate axons to purity has shown that a surprisingly complex transcriptome exists in axons. This extends across different species, neuronal populations, and physiological conditions. These studies have helped define the repertoire of neuronal mRNAs that can localize into axons and imply previously unrecognized functions for local translation in neurons. Here, we review the current state of transcriptomics studies of isolated axons, contrast axonal mRNA profiles between different neuronal types and growth states, and discuss how mRNA transport into and translation within axons contribute to neurological disorders.
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Affiliation(s)
- Amar N Kar
- 1 Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Seung Joon Lee
- 1 Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Jeffery L Twiss
- 1 Department of Biological Sciences, University of South Carolina, Columbia, SC, USA.,2 Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
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28
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Kar AN, Vargas JNS, Chen CY, Kowalak JA, Gioio AE, Kaplan BB. Molecular determinants of cytochrome C oxidase IV mRNA axonal trafficking. Mol Cell Neurosci 2017; 80:32-43. [PMID: 28161363 DOI: 10.1016/j.mcn.2017.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Revised: 01/10/2017] [Accepted: 01/29/2017] [Indexed: 01/17/2023] Open
Abstract
In previous studies, we identified a putative 38-nucleotide stem-loop structure (zipcode) in the 3' untranslated region of the cytochrome c oxidase subunit IV (COXIV) mRNA that was necessary and sufficient for the axonal localization of the message in primary superior cervical ganglion (SCG) neurons. However, little is known about the proteins that interact with the COXIV-zipcode and regulate the axonal trafficking and local translation of the COXIV message. To identify proteins involved in the axonal transport of the COXIV mRNA, we used the biotinylated 38-nucleotide COXIV RNA zipcode as bait in the affinity purification of COXIV zipcode binding proteins. Gel-shift assays of the biotinylated COXIV zipcode indicated that the putative stem-loop structure functions as a nucleation site for the formation of ribonucleoprotein complexes. Mass spectrometric analysis of the COXIV zipcode ribonucleoprotein complex led to the identification of a large number RNA binding proteins, including fused in sarcoma/translated in liposarcoma (FUS/TLS), and Y-box protein 1 (YB-1). Validation experiments, using western analyses, confirmed the presence of the candidate proteins in the COXIV zipcode affinity purified complexes obtained from SCG axons. Immunohistochemical studies show that FUS, and YB-1 are present in SCG axons. Importantly, RNA immunoprecipitation studies show that FUS, and YB-1 interact with endogenous axonal COXIV transcripts. siRNA-mediated downregulation of the candidate proteins FUS and YB-1 expression in the cell-bodies diminishes the levels of COXIV mRNA in the axon, suggesting functional roles for these proteins in the axonal trafficking of COXIV mRNA.
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Affiliation(s)
- Amar N Kar
- Section on Neurobiology, Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Jose Norberto S Vargas
- Section on Neurobiology, Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Cai-Yun Chen
- Section on Neurobiology, Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Jeffrey A Kowalak
- NIMH-NINDS Clinical Proteomics Unit, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Anthony E Gioio
- Section on Neurobiology, Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Barry B Kaplan
- Section on Neurobiology, Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA.
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Xing Z, Yu L, Li X, Su X. Anticancer bioactive peptide-3 inhibits human gastric cancer growth by targeting miR-338-5p. Cell Biosci 2016; 6:53. [PMID: 27688872 PMCID: PMC5034486 DOI: 10.1186/s13578-016-0112-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 06/30/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Cancer incidence and mortality have been increasing in China, making cancer the leading cause of death since 2010 and a major public health concern in the country. Cancer stem cells have been studied in relation to the treatment of different malignancies, including gastric cancer. Anticancer bioactive peptide-3 (ACBP-3) can induce the apoptosis of gastric cancer stem cells (GCSCs) and reduce their tumorigenicity. In the present study, for the first time, we used a miRNA microarray and bioinformatics analysis to identify differentially expressed miRNAs in ACBP-3-treated GCSCs and GCSC-derived tumors in a xenograft model and functionally verified the identified miRNAs. miR-338-5p was selected based on its significant upregulation by ACBP-3 both in cultured GCSCs and in tumor tissues. RESULTS miR-338-5p was downregulated in GCSCs compared with normal gastric epithelial cells, and the ectopic restoration of miR-338-5p expression in GCSCs inhibited cell proliferation and induced apoptosis, which correlated with the upregulation of the pro-apoptotic Bcl-2 proteins BAK and BIM. We also found that ACBP-3-treated GCSCs could respond to lower effective doses of cisplatin (DDP) or 5-fluorouracil (5-FU), possibly because ACBP-3 induced the expression of miR-338-5p and the BAK and BIM proteins and promoted GCSC apoptosis. CONCLUSIONS Our data indicate that miR-338-5p is part of an important pathway for the inhibition of human gastric cancer stem cell proliferation by ACBP-3 combined with chemotherapeutics. ACBP-3 could suppress GCSC proliferation and lower the required effective dose of cisplatin or 5-fluorouracil. Therefore, this study provides not only further evidence for the remarkable anti-tumor effect of ACBP-3 but also a possible new approach for the development of GCSC-targeting therapies.
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Affiliation(s)
- Zhiwei Xing
- Department of Cell Biology, Capital Medical University, Beijing, China
| | - Lan Yu
- The Inner Mongolia Autonomous Region People’s Hospital, Hohhot, Inner Mongolia China
| | - Xian Li
- Clinical Medical Research Center of the Affiliated Hospital, Inner Mongolia Medical University, Hohhot, Inner Mongolia China
| | - Xiulan Su
- Department of Cell Biology, Capital Medical University, Beijing, China
- Clinical Medical Research Center of the Affiliated Hospital, Inner Mongolia Medical University, Hohhot, Inner Mongolia China
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30
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Aschrafi A, Kar AN, Gale JR, Elkahloun AG, Vargas JNS, Sales N, Wilson G, Tompkins M, Gioio AE, Kaplan BB. A heterogeneous population of nuclear-encoded mitochondrial mRNAs is present in the axons of primary sympathetic neurons. Mitochondrion 2016; 30:18-23. [PMID: 27318271 DOI: 10.1016/j.mito.2016.06.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 05/18/2016] [Accepted: 06/14/2016] [Indexed: 10/21/2022]
Abstract
Mitochondria are enriched in subcellular regions of high energy consumption, such as axons and pre-synaptic nerve endings. Accumulating evidence suggests that mitochondrial maintenance in these distal structural/functional domains of the neuron depends on the "in-situ" translation of nuclear-encoded mitochondrial mRNAs. In support of this notion, we recently provided evidence for the axonal targeting of several nuclear-encoded mRNAs, such as cytochrome c oxidase, subunit 4 (COXIV) and ATP synthase, H+ transporting and mitochondrial Fo complex, subunit C1 (ATP5G1). Furthermore, we showed that axonal trafficking and local translation of these mRNAs plays a critical role in the generation of axonal ATP. Using a global gene expression analysis, this study identified a highly diverse population of nuclear-encoded mRNAs that were enriched in the axon and presynaptic nerve terminals. Among this population of mRNAs, fifty seven were found to be at least two-fold more abundant in distal axons, as compared with the parental cell bodies. Gene ontology analysis of the nuclear-encoded mitochondrial mRNAs suggested functions for these gene products in molecular and biological processes, including but not limited to oxidoreductase and electron carrier activity and proton transport. Based on these results, we postulate that local translation of nuclear-encoded mitochondrial mRNAs present in the axons may play an essential role in local energy production and maintenance of mitochondrial function.
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Affiliation(s)
- Armaz Aschrafi
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Amar N Kar
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jenna R Gale
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Abdel G Elkahloun
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jose Noberto S Vargas
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Naomi Sales
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gabriel Wilson
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Miranda Tompkins
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anthony E Gioio
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - Barry B Kaplan
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA.
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31
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Gervasi NM, Scott SS, Aschrafi A, Gale J, Vohra SN, MacGibeny MA, Kar AN, Gioio AE, Kaplan BB. The local expression and trafficking of tyrosine hydroxylase mRNA in the axons of sympathetic neurons. RNA (NEW YORK, N.Y.) 2016; 22:883-95. [PMID: 27095027 PMCID: PMC4878614 DOI: 10.1261/rna.053272.115] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 03/01/2016] [Indexed: 05/06/2023]
Abstract
Synthesis and regulation of catecholamine neurotransmitters in the central nervous system are implicated in the pathogenesis of a number of neuropsychiatric disorders. To identify factors that regulate the presynaptic synthesis of catecholamines, we tested the hypothesis that the rate-limiting enzyme of the catecholamine biosynthetic pathway, tyrosine hydroxylase (TH), is locally synthesized in axons and presynaptic nerve terminals of noradrenergic neurons. To isolate pure axonal mRNA and protein, rat superior cervical ganglion sympathetic neurons were cultured in compartmentalized Campenot chambers. qRT-PCR and RNA in situ hybridization analyses showed that TH mRNA is present in distal axons. Colocalization experiments with nerve terminal marker proteins suggested that both TH mRNA and protein localize in regions of the axon that resemble nerve terminals (i.e., synaptic boutons). Analysis of polysome-bound RNA showed that TH mRNA is present in polysomes isolated from distal axons. Metabolic labeling of axonally synthesized proteins labeled with the methionine analog, L-azidohomoalanine, showed that TH is locally synthesized in axons. Moreover, the local transfection and translation of exogenous TH mRNA into distal axons facilitated axonal dopamine synthesis. Finally, using chimeric td-Tomato-tagged constructs, we identified a sequence element within the TH 3'UTR that is required for the axonal localization of the reporter mRNA. Taken together, our results provide the first direct evidence that TH mRNA is trafficked to the axon and that the mRNA is locally translated. These findings raise the interesting possibility that the biosynthesis of the catecholamine neurotransmitters is locally regulated in the axon and/or presynaptic nerve terminal.
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Affiliation(s)
- Noreen M Gervasi
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Shane S Scott
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Armaz Aschrafi
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jenna Gale
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Sanah N Vohra
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Margaret A MacGibeny
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Amar N Kar
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Anthony E Gioio
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Barry B Kaplan
- Laboratory of Molecular Biology, Division of Intramural Research Programs, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20892, USA
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There and back again: coordinated transcription, translation and transport in axonal survival and regeneration. Curr Opin Neurobiol 2016; 39:62-8. [PMID: 27131422 DOI: 10.1016/j.conb.2016.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 04/07/2016] [Accepted: 04/13/2016] [Indexed: 11/23/2022]
Abstract
Neurons are highly polarized cells with axonal and dendritic projections that extend over long distances. Target-derived neurotrophins provide local axonal cues that function in developing neurons, while physical or chemical injuries to long axons initiate local environmental cues in mature neurons. In both instances initial responses at the location of stimulation or injury must be coordinated with changes in the transcriptional program and subsequent changes in axonal protein content. To achieve this coordination, intracellular signals move 'there and back again' between axons and the nucleus. Here, we review new findings on neuronal responses to growth factors and injury and highlight the coordination of transcription, translation and transport required to mediate communication between axons and cell bodies.
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Yasuda K, Mili S. Dysregulated axonal RNA translation in amyotrophic lateral sclerosis. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:589-603. [PMID: 27038103 PMCID: PMC5071740 DOI: 10.1002/wrna.1352] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 03/01/2016] [Accepted: 03/03/2016] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is an adult‐onset motor neuron disease that has been associated with a diverse array of genetic changes. Prominent among these are mutations in RNA‐binding proteins (RBPs) or repeat expansions that give rise to toxic RNA species. RBPs are additionally central components of pathologic aggregates that constitute a disease hallmark, suggesting that dysregulation of RNA metabolism underlies disease progression. In the context of neuronal physiology, transport of RNAs and localized RNA translation in axons are fundamental to neuronal survival and function. Several lines of evidence suggest that axonal RNA translation is a central process perturbed by various pathogenic events associated with ALS. Dysregulated translation of specific RNA groups could underlie feedback effects that connect and reinforce disease manifestations. Among such candidates are RNAs encoding proteins involved in the regulation of microtubule dynamics. Further understanding of axonally dysregulated RNA targets and of the feedback mechanisms they induce could provide useful therapeutic insights. WIREs RNA 2016, 7:589–603. doi: 10.1002/wrna.1352 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Kyota Yasuda
- Center for Cancer Research, National Institutes of Health, Bethesda, MD, USA
| | - Stavroula Mili
- Center for Cancer Research, National Institutes of Health, Bethesda, MD, USA
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34
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Intra-axonal protein synthesis in development and beyond. Int J Dev Neurosci 2016; 55:140-149. [PMID: 26970010 DOI: 10.1016/j.ijdevneu.2016.03.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/03/2016] [Accepted: 03/07/2016] [Indexed: 12/15/2022] Open
Abstract
Proteins can be locally produced in the periphery of a cell, allowing a rapid and spatially precise response to the changes in its environment. This process is especially relevant in highly polarized and morphologically complex cells such as neurons. The study of local translation in axons has evolved from being primarily focused on developing axons, to the notion that also mature axons can produce proteins. Axonal translation has been implied in several physiological and pathological conditions, and in all cases it shares common molecular actors and pathways as well as regulatory mechanisms. Here, we review the main findings in these fields, and attempt to highlight shared principles.
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35
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Barnhart EL. Mechanics of mitochondrial motility in neurons. Curr Opin Cell Biol 2016; 38:90-9. [DOI: 10.1016/j.ceb.2016.02.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 02/18/2016] [Accepted: 02/25/2016] [Indexed: 11/17/2022]
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36
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De Felice B, Annunziata A, Fiorentino G, Borra M, Biffali E, Coppola C, Cotrufo R, Brettschneider J, Giordana ML, Dalmay T, Wheeler G, D'Alessandro R. miR-338-3p is over-expressed in blood, CFS, serum and spinal cord from sporadic amyotrophic lateral sclerosis patients. Neurogenetics 2014; 15:243-53. [PMID: 25130371 DOI: 10.1007/s10048-014-0420-2] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 08/11/2014] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive and seriously disabling adult-onset neurological disease. Ninety percent of ALS patients are sporadic cases (sALS) with no clear genetic linkage. Accumulating evidence indicates that various microRNAs (miRNAs), expressed in a spatially and temporally controlled manner in the brain, play a key role in neuronal development. In addition, microRNA dysregulation contributes to some mental disorders and neurodegeneration diseases. In our research, the expression of one selected miRNA, miR-338-3p, which previously we have found over-expressed in blood leukocytes, was studied in several different tissues from sALS patients. For the first time, we detected a specific microRNA disease-related upregulation, miR-338-3p, in blood leukocytes as well in cerebrospinal fluid, serum, and spinal cord from sALS patients. Besides, staining of in situ hybridization showed that the signals of miR-338-3p were localized in the grey matter of spinal cord tissues from sALS autopsied patients. We propose that miRNA profiles found in tissue samples from sALS patients can be relevant to understand sALS pathogenesis and lead to set up effective biomarkers for sALS early diagnosis.
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Affiliation(s)
- Bruna De Felice
- DISTABIF-Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Naples II, Via Vivaldi 43, 81100, Caserta, Italy,
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37
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Axonal Transport Defects in Alzheimer’s Disease. Mol Neurobiol 2014; 51:1309-21. [DOI: 10.1007/s12035-014-8810-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2014] [Accepted: 07/10/2014] [Indexed: 10/25/2022]
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38
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Jung H, Gkogkas CG, Sonenberg N, Holt CE. Remote control of gene function by local translation. Cell 2014; 157:26-40. [PMID: 24679524 PMCID: PMC3988848 DOI: 10.1016/j.cell.2014.03.005] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Revised: 02/04/2014] [Accepted: 03/04/2014] [Indexed: 12/12/2022]
Abstract
The subcellular position of a protein is a key determinant of its function. Mounting evidence indicates that RNA localization, where specific mRNAs are transported subcellularly and subsequently translated in response to localized signals, is an evolutionarily conserved mechanism to control protein localization. On-site synthesis confers novel signaling properties to a protein and helps to maintain local proteome homeostasis. Local translation plays particularly important roles in distal neuronal compartments, and dysregulated RNA localization and translation cause defects in neuronal wiring and survival. Here, we discuss key findings in this area and possible implications of this adaptable and swift mechanism for spatial control of gene function.
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Affiliation(s)
- Hosung Jung
- Department of Anatomy, Brain Research Institute, and Brain Korea 21 PLUS Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, South Korea
| | - Christos G Gkogkas
- Patrick Wild Centre, Centre for Integrative Physiology, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Research Centre, McGill University, Montreal, QC H3A 1A3, Canada.
| | - Christine E Holt
- Department of Physiology Development and Neuroscience, Anatomy Building, Downing Street, University of Cambridge, Cambridge CB2 3DY, UK.
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Spillane M, Ketschek A, Merianda TT, Twiss JL, Gallo G. Mitochondria coordinate sites of axon branching through localized intra-axonal protein synthesis. Cell Rep 2013; 5:1564-75. [PMID: 24332852 DOI: 10.1016/j.celrep.2013.11.022] [Citation(s) in RCA: 201] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 09/30/2013] [Accepted: 11/12/2013] [Indexed: 11/16/2022] Open
Abstract
The branching of axons is a fundamental aspect of nervous system development and neuroplasticity. We report that branching of sensory axons in the presence of nerve growth factor (NGF) occurs at sites populated by stalled mitochondria. Translational machinery targets to presumptive branching sites, followed by recruitment of mitochondria to these sites. The mitochondria promote branching through ATP generation and the determination of localized hot spots of active axonal mRNA translation, which contribute to actin-dependent aspects of branching. In contrast, mitochondria do not have a role in the regulation of the microtubule cytoskeleton during NGF-induced branching. Collectively, these observations indicate that sensory axons exhibit multiple potential sites of translation, defined by presence of translational machinery, but active translation occurs following the stalling and respiration of mitochondria at these potential sites of translation. This study reveals a local role for axonal mitochondria in the regulation of the actin cytoskeleton and axonal mRNA translation underlying branching.
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Affiliation(s)
- Mirela Spillane
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - Andrea Ketschek
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA
| | - Tanuja T Merianda
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, 2900 Queen Lane, Philadelphia, PA 19210, USA
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, 715 Sumter Street, Columbia, SC 29208, USA
| | - Gianluca Gallo
- Department of Anatomy and Cell Biology, Shriners Hospitals Pediatric Research Center, Temple University, 3500 North Broad Street, Philadelphia, PA 19140, USA.
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40
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Kar AN, Sun CY, Reichard K, Gervasi NM, Pickel J, Nakazawa K, Gioio AE, Kaplan BB. Dysregulation of the axonal trafficking of nuclear-encoded mitochondrial mRNA alters neuronal mitochondrial activity and mouse behavior. Dev Neurobiol 2013; 74:333-50. [PMID: 24151253 DOI: 10.1002/dneu.22141] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 09/03/2013] [Accepted: 10/16/2013] [Indexed: 01/22/2023]
Abstract
Local translation of nuclear-encoded mitochondrial mRNAs is essential for mitochondrial activity, yet there is little insight into the role that axonal trafficking of these transcripts play in neuronal function and behavior. Previously, we identified a 38 nucleotide stem-loop structure (zipcode) in the 3' untranslated region of the Cytochrome C oxidase IV (COXIV) mRNA that directs the transport of a reporter mRNA to the axon of superior cervical ganglion neurons (SCG). Overexpression of a chimeric reporter mRNA with the COXIV zipcode competed with the axonal trafficking of endogenous COXIV mRNA, and led to attenuated axon growth in SCG neurons. Here, we show that exogenous expression of the COXIV zipcode in cultured SCG neurons also results in the reduction of local ATP levels and increases levels of reactive oxygen species (ROS) in the axon. We took advantage of this "competition" phenotype to investigate the in vivo significance of axonal transport of COXIV mRNA. Toward this end, we generated transgenic mice expressing a fluorescent reporter fused to COXIV zipcode under a forebrain-specific promoter. Immunohistological analyses and RT-PCR analyses of RNA from the transgenic mouse brain showed expression of the reporter in the deep layer neurons in the pre-frontal and frontal cortex. Consistent with the in vitro studies, we observed increased ROS levels in neurons of these transgenic animals. A battery of behavioral tests on transgenic mice expressing the COXIV zipcode revealed an "anxiety-like" behavioral phenotype, suggesting an important role for axonal trafficking of nuclear-encoded mitochondrial mRNAs in neuronal physiology and animal behavior.
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Affiliation(s)
- Amar N Kar
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland, 20892
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Minis A, Dahary D, Manor O, Leshkowitz D, Pilpel Y, Yaron A. Subcellular transcriptomics-Dissection of the mRNA composition in the axonal compartment of sensory neurons. Dev Neurobiol 2013; 74:365-81. [DOI: 10.1002/dneu.22140] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2013] [Revised: 09/06/2013] [Accepted: 10/03/2013] [Indexed: 12/19/2022]
Affiliation(s)
- Adi Minis
- Department of Biological Chemistry; Weizmann Institute of Science; Rehovot 76100 Israel
| | - Dvir Dahary
- Department of Molecular Genetics; Weizmann Institute of Science; Rehovot 76100 Israel
| | - Ohad Manor
- Department of Computer Science and Applied Mathematics; Weizmann Institute of Science; Rehovot 76100 Israel
| | - Dena Leshkowitz
- Biological Services Department; Bioinformatics Unit, Weizmann Institute of Science; Rehovot 76100 Israel
| | - Yitzhak Pilpel
- Department of Molecular Genetics; Weizmann Institute of Science; Rehovot 76100 Israel
| | - Avraham Yaron
- Department of Biological Chemistry; Weizmann Institute of Science; Rehovot 76100 Israel
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42
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Crispino M, Chun JT, Cefaliello C, Perrone Capano C, Giuditta A. Local gene expression in nerve endings. Dev Neurobiol 2013; 74:279-91. [PMID: 23853157 DOI: 10.1002/dneu.22109] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Revised: 06/28/2013] [Accepted: 07/05/2013] [Indexed: 12/11/2022]
Abstract
At the Nobel lecture for physiology in 1906, Ramón y Cajal famously stated that "the nerve elements possess reciprocal relationships in contiguity but not in continuity," summing up the neuron doctrine. Sixty years later, by the time the central dogma of molecular biology formulated the axis of genetic information flow from DNA to mRNA, and then to protein, it became obvious that neurons with extensive ramifications and long axons inevitably incur an innate problem: how can the effect of gene expression be extended from the nucleus to the remote and specific sites of the cell periphery? The most straightforward solution would be to deliver soma-produced proteins to the target sites. The influential discovery of axoplasmic flow has supported this scheme of protein supply. Alternatively, mRNAs can be dispatched instead of protein, and translated locally at the strategic target sites. Over the past decades, such a local system of protein synthesis has been demonstrated in dendrites, axons, and presynaptic terminals. Moreover, the local protein synthesis in neurons might even involve intercellular trafficking of molecules. The innovative concept of glia-neuron unit suggests that the local protein synthesis in the axonal and presynaptic domain of mature neurons is sustained by a local supply of RNAs synthesized in the surrounding glial cells and transferred to these domains. Here, we have reviewed some of the evidence indicating the presence of a local system of protein synthesis in axon terminals, and have examined its regulation in various model systems.
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Affiliation(s)
- Marianna Crispino
- Department of Biology, University of Naples Federico II, Naples, Italy
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43
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Deglincerti A, Jaffrey SR. Insights into the roles of local translation from the axonal transcriptome. Open Biol 2013; 2:120079. [PMID: 22773949 PMCID: PMC3390793 DOI: 10.1098/rsob.120079] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 05/22/2012] [Indexed: 11/12/2022] Open
Abstract
Much of our knowledge on the roles of intra-axonal translation derives from the characterization of a small number of individual mRNAs that were found to be localized in axons. However, two recent studies, using large-scale approaches to provide a more comprehensive characterization of the axonal transcriptome, have led to the discovery of thousands of axonal mRNAs. The apparent abundance of mRNAs in axons raises the possibility that local translation has many more functions than previously thought. Here, we review the recent studies that have profiled axonal mRNAs and discuss how the identification of axonal transcripts might point to unappreciated roles for local translation in axons.
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Affiliation(s)
- Alessia Deglincerti
- Graduate Program in Neuroscience, Weill Cornell Graduate School of Medical Sciences of Cornell University, 1300 York Avenue, New York, NY 10065, USA
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44
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Abstract
Neurons, perhaps more than any other cell type, depend on mitochondrial trafficking for their survival. Recent studies have elucidated a motor/adaptor complex on the mitochondrial surface that is shared between neurons and other animal cells. In addition to kinesin and dynein, this complex contains the proteins Miro (also called RhoT1/2) and milton (also called TRAK1/2) and is responsible for much, although not necessarily all, mitochondrial movement. Elucidation of the complex has permitted inroads for understanding how this movement is regulated by a variety of intracellular signals, although many mysteries remain. Regulating mitochondrial movement can match energy demand to energy supply throughout the extraordinary architecture of these cells and can control the clearance and replenishing of mitochondria in the periphery. Because the extended axons of neurons contain uniformly polarized microtubules, they have been useful for studying mitochondrial motility in conjunction with biochemical assays in many cell types.
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Affiliation(s)
- Thomas L Schwarz
- F.M. Kirby Neurobiology Center, Children's Hospital Boston, and Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA.
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45
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Aschrafi A, Kar AN, Natera-Naranjo O, MacGibeny MA, Gioio AE, Kaplan BB. MicroRNA-338 regulates the axonal expression of multiple nuclear-encoded mitochondrial mRNAs encoding subunits of the oxidative phosphorylation machinery. Cell Mol Life Sci 2012; 69:4017-27. [PMID: 22773120 PMCID: PMC11114659 DOI: 10.1007/s00018-012-1064-8] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Revised: 06/08/2012] [Accepted: 06/19/2012] [Indexed: 11/24/2022]
Abstract
MicroRNAs (miRNAs) constitute a novel class of small, non-coding RNAs that act as post-transcriptional regulators of gene expression. Remarkably, it has been shown that these small molecules can coordinately regulate multiple genes coding for proteins with related cellular functions. Previously, we reported that brain-specific miR-338 modulates the axonal expression of cytochrome c oxidase IV (COXIV), a nuclear-encoded mitochondrial protein that plays a key role in oxidative phosphorylation and axonal function. Here, we report that ATP synthase (ATP5G1), like COXIV mRNA, contains a putative miR-338 binding site, and that modulation of miR-338 levels in the axon results in alterations in both COXIV and ATP5G1 expression. Importantly, miR-338 modulation of local COXIV and ATP5G1 expression has a marked effect on axonal ROS levels, as well as axonal growth. These findings point to a mechanism by which miR-338 modulates local energy metabolism through the coordinate regulation of the expression of multiple nuclear-encoded mitochondrial mRNAs in the axon.
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Affiliation(s)
- Armaz Aschrafi
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1381 USA
| | - Amar N. Kar
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1381 USA
| | - Orlangie Natera-Naranjo
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1381 USA
| | - Margaret A. MacGibeny
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1381 USA
| | - Anthony E. Gioio
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1381 USA
| | - Barry B. Kaplan
- Laboratory of Molecular Biology, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1381 USA
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46
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Lou DD, Guan ZZ, Liu YJ, Liu YF, Zhang KL, Pan JG, Pei JJ. The influence of chronic fluorosis on mitochondrial dynamics morphology and distribution in cortical neurons of the rat brain. Arch Toxicol 2012; 87:449-57. [PMID: 23007560 DOI: 10.1007/s00204-012-0942-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 09/10/2012] [Indexed: 11/25/2022]
Abstract
The present study was designed to evaluate the effects of chronic fluorosis on the dynamics (including fusion and fission proteins), fragmentation, and distribution of mitochondria in the cortical neurons of the rat brain in an attempt to elucidate molecular mechanisms underlying the brain damage associated with excess accumulation of fluoride. Sixty Sprague-Dawley rats were divided randomly into three groups of 20 each, that is, the untreated control group (drinking water naturally containing <0.5 mg fluoride/l, NaF), the low-fluoride group (whose drinking water was supplemented with 10 mg fluoride/l) and the high-fluoride group (50 mg fluoride/l). After 6 months of exposure, the expression of mitofusin-1 (Mfn1), fission-1 (Fis1), and dynamin-related protein-1 (Drp1) at both the protein and mRNA levels were detected by Western blotting, immunohistochemistry, and real-time PCR, respectively. Moreover, mitochondrial morphology and distribution in neurons were observed by transmission electron or fluorescence microscopy. In the cortices of the brains of rats with chronic fluorosis, the level of Mfn1 protein was clearly reduced, whereas the levels of Fis1 and Drp1 were elevated. The alternations of expression of the mRNAs encoding all three of these proteins were almost the same as the corresponding changes at the protein levels. The mitochondria were fragmented and the redistributed away from the axons of the cortical neurons. These findings indicate that chronic fluorosis induces abnormal mitochondrial dynamics, which might in turn result in a high level of oxidative stress.
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Affiliation(s)
- Di-Dong Lou
- Department of Pathology, Guiyang Medical University, Guiyang, 550004, People's Republic of China
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47
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Jung H, Yoon BC, Holt CE. Axonal mRNA localization and local protein synthesis in nervous system assembly, maintenance and repair. Nat Rev Neurosci 2012; 13:308-24. [PMID: 22498899 PMCID: PMC3682205 DOI: 10.1038/nrn3210] [Citation(s) in RCA: 337] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
mRNAs can be targeted to specific neuronal subcellular domains, which enables rapid changes in the local proteome through local translation. This mRNA-based mechanism links extrinsic signals to spatially restricted cellular responses and can mediate stimulus-driven adaptive responses such as dendritic plasticity. Local mRNA translation also occurs in growing axons where it can mediate directional responses to guidance signals. Recent profiling studies have revealed that both growing and mature axons possess surprisingly complex and dynamic transcriptomes, thereby suggesting that axonal mRNA localization is highly regulated and has a role in a broad range of processes, a view that is increasingly being supported by new experimental evidence. Here, we review current knowledge on the roles and regulatory mechanisms of axonal mRNA translation and discuss emerging links to axon guidance, survival, regeneration and neurological disorders.
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Affiliation(s)
- Hosung Jung
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
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48
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A potential regulatory role for intronic microRNA-338-3p for its host gene encoding apoptosis-associated tyrosine kinase. PLoS One 2012; 7:e31022. [PMID: 22363537 PMCID: PMC3281898 DOI: 10.1371/journal.pone.0031022] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 12/31/2011] [Indexed: 12/13/2022] Open
Abstract
MicroRNAs (miRNAs) are important gene regulators that are abundantly expressed in both the developing and adult mammalian brain. These non-coding gene transcripts are involved in post-transcriptional regulatory processes by binding to specific target mRNAs. Approximately one third of known miRNA genes are located within intronic regions of protein coding and non-coding regions, and previous studies have suggested a role for intronic miRNAs as negative feedback regulators of their host genes. In the present study, we monitored the dynamic gene expression changes of the intronic miR-338-3p and miR-338-5p and their host gene Apoptosis-associated Tyrosine Kinase (AATK) during the maturation of rat hippocampal neurons. This revealed an uncorrelated expression pattern of mature miR-338 strands with their host gene. Sequence analysis of the 3′ untranslated region (UTR) of rat AATK mRNA revealed the presence of two putative binding sites for miR-338-3p. Thus, miR-338-3p may have the capacity to modulate AATK mRNA levels in neurons. Transfection of miR-338-3p mimics into rat B35 neuroblastoma cells resulted in a significant decrease of AATK mRNA levels, while the transfection of synthetic miR-338-5p mimics did not alter AATK levels. Our results point to a possible molecular mechanism by which miR-338-3p participates in the regulation of its host gene by modulating the levels of AATK mRNA, a kinase which plays a role during differentiation, apoptosis and possibly in neuronal degeneration.
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49
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Yoon B, Jung H, Dwivedy A, O'Hare C, Zivraj K, Holt C. Local translation of extranuclear lamin B promotes axon maintenance. Cell 2012; 148:752-64. [PMID: 22341447 PMCID: PMC3314965 DOI: 10.1016/j.cell.2011.11.064] [Citation(s) in RCA: 209] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 09/26/2011] [Accepted: 11/18/2011] [Indexed: 12/27/2022]
Abstract
Local protein synthesis plays a key role in regulating stimulus-induced responses in dendrites and axons. Recent genome-wide studies have revealed that thousands of different transcripts reside in these distal neuronal compartments, but identifying those with functionally significant roles presents a challenge. We performed an unbiased screen to look for stimulus-induced, protein synthesis-dependent changes in the proteome of Xenopus retinal ganglion cell (RGC) axons. The intermediate filament protein lamin B2 (LB2), normally associated with the nuclear membrane, was identified as an unexpected major target. Axonal ribosome immunoprecipitation confirmed translation of lb2 mRNA in vivo. Inhibition of lb2 mRNA translation in axons in vivo does not affect guidance but causes axonal degeneration. Axonal LB2 associates with mitochondria, and LB2-deficient axons exhibit mitochondrial dysfunction and defects in axonal transport. Our results thus suggest that axonally synthesized lamin B plays a crucial role in axon maintenance by promoting mitochondrial function.
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Affiliation(s)
- Byung C. Yoon
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Hosung Jung
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Asha Dwivedy
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Catherine M. O'Hare
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Krishna H. Zivraj
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
| | - Christine E. Holt
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK
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50
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Ye X, Tai W, Zhang D. The early events of Alzheimer's disease pathology: from mitochondrial dysfunction to BDNF axonal transport deficits. Neurobiol Aging 2011; 33:1122.e1-10. [PMID: 22212405 DOI: 10.1016/j.neurobiolaging.2011.11.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 11/01/2011] [Accepted: 11/04/2011] [Indexed: 01/05/2023]
Abstract
Although there are numerous studies regarding Alzheimer's disease (AD), the cause and progression of AD are still not well understood. The researches in the past decade implicated amyloid-beta (Aβ) overproduction as a causative event in disease pathogenesis, but still failed to clarify the mechanism of pathology from Aβ production to central neural system defects in AD. The present review raises the hypothesis that the onset of AD pathology is closely related with mitochondrial dysfunction induced by Aβ and brain-derived neurotrophic factor (BDNF) axonal transport deficits. It is well-known that axonal transport defect and attenuation of BDNF-neurotrophic tyrosine receptor kinase 2 (TrkB) signal are fatal to neuronal function and survival. We hypothesized that abnormal amyloid precursor protein (APP) processing and Aβ production in mitochondria disturb the axonal transport by impairing mitochondrial function and attenuate BDNF-neurotrophic tyrosine receptor kinase 2 signal subsequently. For this hypothesis, the factors related with the initiation of AD pathology are not only limited to the neurons per se but also expanded to the microenvironment around neurons, such as the secretion of BDNF from astrocytes. The modification of the origin in this pathway may contribute to slow down the disease progression of AD.
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Affiliation(s)
- Xuan Ye
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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