1
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Koppers M, Özkan N, Nguyen HH, Jurriens D, McCaughey J, Nguyen DTM, Li CH, Stucchi R, Altelaar M, MacGillavry HD, Kapitein LC, Hoogenraad CC, Farías GG. Axonal endoplasmic reticulum tubules control local translation via P180/RRBP1-mediated ribosome interactions. Dev Cell 2024:S1534-5807(24)00322-8. [PMID: 38815583 DOI: 10.1016/j.devcel.2024.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/31/2024] [Accepted: 05/09/2024] [Indexed: 06/01/2024]
Abstract
Local mRNA translation in axons is critical for the spatiotemporal regulation of the axonal proteome. A wide variety of mRNAs are localized and translated in axons; however, how protein synthesis is regulated at specific subcellular sites in axons remains unclear. Here, we establish that the axonal endoplasmic reticulum (ER) supports axonal translation in developing rat hippocampal cultured neurons. Axonal ER tubule disruption impairs local translation and ribosome distribution. Using nanoscale resolution imaging, we find that ribosomes make frequent contacts with axonal ER tubules in a translation-dependent manner and are influenced by specific extrinsic cues. We identify P180/RRBP1 as an axonally distributed ribosome receptor that regulates local translation and binds to mRNAs enriched for axonal membrane proteins. Importantly, the impairment of axonal ER-ribosome interactions causes defects in axon morphology. Our results establish a role for the axonal ER in dynamically localizing mRNA translation, which is important for proper neuron development.
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Affiliation(s)
- Max Koppers
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands.
| | - Nazmiye Özkan
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Ha H Nguyen
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Daphne Jurriens
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Janine McCaughey
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Dan T M Nguyen
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Chun Hei Li
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Riccardo Stucchi
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands; Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Harold D MacGillavry
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Lukas C Kapitein
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands; Department of Neuroscience, Genentech, Inc., South San Francisco, CA 94080, USA
| | - Ginny G Farías
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands.
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2
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Cagnetta R, Flanagan JG, Sonenberg N. Control of Selective mRNA Translation in Neuronal Subcellular Compartments in Health and Disease. J Neurosci 2023; 43:7247-7263. [PMID: 37914402 PMCID: PMC10621772 DOI: 10.1523/jneurosci.2240-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 11/03/2023] Open
Abstract
In multiple cell types, mRNAs are transported to subcellular compartments, where local translation enables rapid, spatially localized, and specific responses to external stimuli. Mounting evidence has uncovered important roles played by local translation in vivo in axon survival, axon regeneration, and neural wiring, as well as strong links between dysregulation of local translation and neurologic disorders. Omic studies have revealed that >1000 mRNAs are present and can be selectively locally translated in the presynaptic and postsynaptic compartments from development to adulthood in vivo A large proportion of the locally translated mRNAs is specifically upregulated or downregulated in response to distinct extracellular signals. Given that the local translatome is large, selectively translated, and cue-specifically remodeled, a fundamental question concerns how selective translation is achieved locally. Here, we review the emerging regulatory mechanisms of local selective translation in neuronal subcellular compartments, their mRNA targets, and their orchestration. We discuss mechanisms of local selective translation that remain unexplored. Finally, we describe clinical implications and potential therapeutic strategies in light of the latest advances in gene therapy.
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Affiliation(s)
- Roberta Cagnetta
- Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal, Quebec H3A 1A3, Canada
| | - John G Flanagan
- Department of Cell Biology and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02115
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal, Quebec H3A 1A3, Canada
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3
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Patel P, Buchanan CN, Zdradzinski MD, Sahoo PK, Kar A, Lee S, Vaughn L, Urisman A, Oses-Prieto J, Dell’Orco M, Cassidy D, Costa I, Miller S, Thames E, Smith T, Burlingame A, Perrone-Bizzozero N, Twiss J. Intra-axonal translation of Khsrp mRNA slows axon regeneration by destabilizing localized mRNAs. Nucleic Acids Res 2022; 50:5772-5792. [PMID: 35556128 PMCID: PMC9177972 DOI: 10.1093/nar/gkac337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 04/21/2022] [Accepted: 05/09/2022] [Indexed: 11/28/2022] Open
Abstract
Axonally synthesized proteins support nerve regeneration through retrograde signaling and local growth mechanisms. RNA binding proteins (RBP) are needed for this and other aspects of post-transcriptional regulation of neuronal mRNAs, but only a limited number of axonal RBPs are known. We used targeted proteomics to profile RBPs in peripheral nerve axons. We detected 76 proteins with reported RNA binding activity in axoplasm, and levels of several change with axon injury and regeneration. RBPs with altered levels include KHSRP that decreases neurite outgrowth in developing CNS neurons. Axonal KHSRP levels rapidly increase after injury remaining elevated up to 28 days post axotomy. Khsrp mRNA localizes into axons and the rapid increase in axonal KHSRP is through local translation of Khsrp mRNA in axons. KHSRP can bind to mRNAs with 3'UTR AU-rich elements and targets those transcripts to the cytoplasmic exosome for degradation. KHSRP knockout mice show increased axonal levels of KHSRP target mRNAs, Gap43, Snap25, and Fubp1, following sciatic nerve injury and these mice show accelerated nerve regeneration in vivo. Together, our data indicate that axonal translation of the RNA binding protein Khsrp mRNA following nerve injury serves to promote decay of other axonal mRNAs and slow axon regeneration.
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Affiliation(s)
- Priyanka Patel
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Courtney N Buchanan
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Matthew D Zdradzinski
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Lauren S Vaughn
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Anatoly Urisman
- Department of Pharmaceutical Sciences, University of California, San Francisco, CA 94143, USA
| | - Juan Oses-Prieto
- Department of Pharmaceutical Sciences, University of California, San Francisco, CA 94143, USA
| | - Michela Dell’Orco
- Department of Neurosciences, University of New Mexico School of Health Sciences, Albuquerque, NM 87131, USA
| | - Devon E Cassidy
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Irene Dalla Costa
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Sharmina Miller
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Elizabeth Thames
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Terika P Smith
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Alma L Burlingame
- Department of Pharmaceutical Sciences, University of California, San Francisco, CA 94143, USA
| | - Nora Perrone-Bizzozero
- Department of Neurosciences, University of New Mexico School of Health Sciences, Albuquerque, NM 87131, USA
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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Li L, Yu J, Ji SJ. Axonal mRNA localization and translation: local events with broad roles. Cell Mol Life Sci 2021; 78:7379-7395. [PMID: 34698881 PMCID: PMC11072051 DOI: 10.1007/s00018-021-03995-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 09/17/2021] [Accepted: 10/14/2021] [Indexed: 12/19/2022]
Abstract
Messenger RNA (mRNA) can be transported and targeted to different subcellular compartments and locally translated. Local translation is an evolutionally conserved mechanism that in mammals, provides an important tool to exquisitely regulate the subcellular proteome in different cell types, including neurons. Local translation in axons is involved in processes such as neuronal development, function, plasticity, and diseases. Here, we summarize the current progress on axonal mRNA transport and translation. We focus on the regulatory mechanisms governing how mRNAs are transported to axons and how they are locally translated in axons. We discuss the roles of axonally synthesized proteins, which either function locally in axons, or are retrogradely trafficked back to soma to achieve neuron-wide gene regulation. We also examine local translation in neurological diseases. Finally, we give a critical perspective on the remaining questions that could be answered to uncover the fundamental rules governing local translation, and discuss how this could lead to new therapeutic targets for neurological diseases.
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Affiliation(s)
- Lichao Li
- School of Life Sciences, Department of Biology, Shenzhen Key Laboratory of Gene Regulation and Systems Biology, Brain Research Center, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, China
| | - Jun Yu
- School of Life Sciences, Department of Biology, Shenzhen Key Laboratory of Gene Regulation and Systems Biology, Brain Research Center, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, China
| | - Sheng-Jian Ji
- School of Life Sciences, Department of Biology, Shenzhen Key Laboratory of Gene Regulation and Systems Biology, Brain Research Center, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, China.
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5
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MicroRNAs 21 and 199a-3p Regulate Axon Growth Potential through Modulation of Pten and mTor mRNAs. eNeuro 2021; 8:ENEURO.0155-21.2021. [PMID: 34326064 PMCID: PMC8362682 DOI: 10.1523/eneuro.0155-21.2021] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 07/11/2021] [Accepted: 07/15/2021] [Indexed: 12/14/2022] Open
Abstract
Increased mTOR activity has been shown to enhance regeneration of injured axons by increasing neuronal protein synthesis, while PTEN signaling can block mTOR activity to attenuate protein synthesis. MicroRNAs (miRs) have been implicated in regulation of PTEN and mTOR expression, and previous work in spinal cord showed an increase in miR-199a-3p after spinal cord injury (SCI) and increase in miR-21 in SCI animals that had undergone exercise. Pten mRNA is a target for miR-21 and miR-199a-3p is predicted to target mTor mRNA. Here, we show that miR-21 and miR-199a-3p are expressed in adult dorsal root ganglion (DRG) neurons, and we used culture preparations to test functions of the rat miRs in adult DRG and embryonic cortical neurons. miR-21 increases and miR-199a-3p decreases in DRG neurons after in vivo axotomy. In both the adult DRG and embryonic cortical neurons, miR-21 promotes and miR-199a-3p attenuates neurite growth. miR-21 directly bound to Pten mRNA and miR-21 overexpression decreased Pten mRNA levels. Conversely, miR-199a-3p directly bound to mTor mRNA and miR-199a-3p overexpression decreased mTor mRNA levels. Overexpressing miR-21 increased both overall and intra-axonal protein synthesis in cultured DRGs, while miR-199a-3p overexpression decreased this protein synthesis. The axon growth phenotypes seen with miR-21 and miR-199a-3p overexpression were reversed by co-transfecting PTEN and mTOR cDNA expression constructs with the predicted 3′ untranslated region (UTR) miR target sequences deleted. Taken together, these studies indicate that injury-induced alterations in miR-21 and miR-199a-3p expression can alter axon growth capacity by changing overall and intra-axonal protein synthesis through regulation of the PTEN/mTOR pathway.
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6
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Axonal Organelles as Molecular Platforms for Axon Growth and Regeneration after Injury. Int J Mol Sci 2021; 22:ijms22041798. [PMID: 33670312 PMCID: PMC7918155 DOI: 10.3390/ijms22041798] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023] Open
Abstract
Investigating the molecular mechanisms governing developmental axon growth has been a useful approach for identifying new strategies for boosting axon regeneration after injury, with the goal of treating debilitating conditions such as spinal cord injury and vision loss. The picture emerging is that various axonal organelles are important centers for organizing the molecular mechanisms and machinery required for growth cone development and axon extension, and these have recently been targeted to stimulate robust regeneration in the injured adult central nervous system (CNS). This review summarizes recent literature highlighting a central role for organelles such as recycling endosomes, the endoplasmic reticulum, mitochondria, lysosomes, autophagosomes and the proteasome in developmental axon growth, and describes how these organelles can be targeted to promote axon regeneration after injury to the adult CNS. This review also examines the connections between these organelles in developing and regenerating axons, and finally discusses the molecular mechanisms within the axon that are required for successful axon growth.
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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: 77] [Impact Index Per Article: 25.7] [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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Sahoo PK, Kar AN, Samra N, Terenzio M, Patel P, Lee SJ, Miller S, Thames E, Jones B, Kawaguchi R, Coppola G, Fainzilber M, Twiss JL. A Ca 2+-Dependent Switch Activates Axonal Casein Kinase 2α Translation and Drives G3BP1 Granule Disassembly for Axon Regeneration. Curr Biol 2020; 30:4882-4895.e6. [PMID: 33065005 DOI: 10.1016/j.cub.2020.09.043] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 07/15/2020] [Accepted: 09/14/2020] [Indexed: 12/20/2022]
Abstract
The main limitation on axon regeneration in the peripheral nervous system (PNS) is the slow rate of regrowth. We recently reported that nerve regeneration can be accelerated by axonal G3BP1 granule disassembly, releasing axonal mRNAs for local translation to support axon growth. Here, we show that G3BP1 phosphorylation by casein kinase 2α (CK2α) triggers G3BP1 granule disassembly in injured axons. CK2α activity is temporally and spatially regulated by local translation of Csnk2a1 mRNA in axons after injury, but this requires local translation of mTor mRNA and buffering of the elevated axonal Ca2+ that occurs after axotomy. CK2α's appearance in axons after PNS nerve injury correlates with disassembly of axonal G3BP1 granules as well as increased phospho-G3BP1 and axon growth, although depletion of Csnk2a1 mRNA from PNS axons decreases regeneration and increases G3BP1 granules. Phosphomimetic G3BP1 shows remarkably decreased RNA binding in dorsal root ganglion (DRG) neurons compared with wild-type and non-phosphorylatable G3BP1; combined with other studies, this suggests that CK2α-dependent G3BP1 phosphorylation on Ser 149 after axotomy releases axonal mRNAs for translation. Translation of axonal mRNAs encoding some injury-associated proteins is known to be increased with Ca2+ elevations, and using a dual fluorescence recovery after photobleaching (FRAP) reporter assay for axonal translation, we see that translational specificity switches from injury-associated protein mRNA translation to CK2α translation with endoplasmic reticulum (ER) Ca2+ release versus cytoplasmic Ca2+ chelation. Our results point to axoplasmic Ca2+ concentrations as a determinant for the temporal specificity of sequential translational activation of different axonal mRNAs as severed axons transition from injury to regenerative growth.
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Affiliation(s)
- Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Nitzan Samra
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovat, Israel
| | - Marco Terenzio
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovat, Israel; Molecular Neuroscience Unit, Okinawa Institute of Science and Technology, Kunigami, Okinawa 904-0412, Japan
| | - Priyanka Patel
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Sharmina Miller
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Elizabeth Thames
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Blake Jones
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Riki Kawaguchi
- Department of Neurology, Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA 90095-1761, USA
| | - Giovanni Coppola
- Department of Neurology, Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA 90095-1761, USA
| | - Mike Fainzilber
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovat, Israel
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.
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9
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Smith TP, Sahoo PK, Kar AN, Twiss JL. Intra-axonal mechanisms driving axon regeneration. Brain Res 2020; 1740:146864. [PMID: 32360100 DOI: 10.1016/j.brainres.2020.146864] [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: 01/05/2020] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 12/27/2022]
Abstract
Traumatic injury to the peripheral and central nervous systems very often causes axotomy, where an axon loses connections with its target resulting in loss of function. The axon segments distal to the injury site lose connection with the cell body and degenerate. Axotomized neurons in the periphery can spontaneously mount a regenerative response and reconnect to their denervated target tissues, though this is rarely complete in humans. In contrast, spontaneous regeneration rarely occurs after axotomy in the spinal cord and brain. Here, we concentrate on the mechanisms underlying this spontaneous regeneration in the peripheral nervous system, focusing on events initiated from the axon that support regenerative growth. We contrast this with what is known for axonal injury responses in the central nervous system. Considering the neuropathy focus of this special issue, we further draw parallels and distinctions between the injury-response mechanisms that initiate regenerative gene expression programs and those that are known to trigger axon degeneration.
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Affiliation(s)
- Terika P Smith
- 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
| | - 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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10
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Pacheco A, Merianda TT, Twiss JL, Gallo G. Mechanism and role of the intra-axonal Calreticulin translation in response to axonal injury. Exp Neurol 2019; 323:113072. [PMID: 31669485 DOI: 10.1016/j.expneurol.2019.113072] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/17/2019] [Accepted: 09/27/2019] [Indexed: 12/12/2022]
Abstract
Following injury, sensory axons locally translate mRNAs that encode proteins needed for the response to injury, locally and through retrograde signaling, and for regeneration. In this study, we addressed the mechanism and role of axotomy-induced intra-axonal translation of the ER chaperone Calreticulin. In vivo peripheral nerve injury increased Calreticulin levels in sensory axons. Using an in vitro model system of sensory neurons amenable to mechanistic dissection we provide evidence that axotomy induces local translation of Calreticulin through PERK (protein kinase RNA-like endoplasmic reticulum kinase) mediated phosphorylation of eIF2α by a mechanism that requires both 5' and 3'UTRs (untranslated regions) elements in Calreticulin mRNA. ShRNA mediated depletion of Calreticulin or inhibition of PERK signaling increased axon retraction following axotomy. In contrast, expression of axonally targeted, but not somatically restricted, Calreticulin mRNA decreased retraction and promoted axon regeneration following axotomy in vitro. Collectively, these data indicate that the intra-axonal translation of Calreticulin in response to axotomy serves to minimize the ensuing retraction, and overexpression of axonally targeted Calreticulin mRNA promotes axon regeneration.
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Affiliation(s)
- Almudena Pacheco
- Temple University School of Medicine, Shriners Pediatric Research Center, Department of Anatomy and Cell Biology, 3500 North Broad St, Philadelphia, PA 19140, United States of America.
| | - Tanuja T Merianda
- Drexel University, Department of Biology, Philadelphia, PA 19104, United States of America
| | - Jeffery L Twiss
- University of South Carolina, Department of Biological Sciences, Columbia 29208, SC, United States of America.
| | - Gianluca Gallo
- Temple University School of Medicine, Shriners Pediatric Research Center, Department of Anatomy and Cell Biology, 3500 North Broad St, Philadelphia, PA 19140, United States of America.
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11
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Cagnetta R, Wong HHW, Frese CK, Mallucci GR, Krijgsveld J, Holt CE. Noncanonical Modulation of the eIF2 Pathway Controls an Increase in Local Translation during Neural Wiring. Mol Cell 2018; 73:474-489.e5. [PMID: 30595434 PMCID: PMC6375727 DOI: 10.1016/j.molcel.2018.11.013] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 09/18/2018] [Accepted: 11/13/2018] [Indexed: 12/22/2022]
Abstract
Local translation is rapidly regulated by extrinsic signals during neural wiring, but its control mechanisms remain elusive. Here we show that the extracellular cue Sema3A induces an initial burst in local translation that precisely controls phosphorylation of the translation initiation factor eIF2α via the unfolded protein response (UPR) kinase PERK. Strikingly, in contrast to canonical UPR signaling, Sema3A-induced eIF2α phosphorylation bypasses global translational repression and underlies an increase in local translation through differential activity of eIF2B mediated by protein phosphatase 1. Ultrasensitive proteomics analysis of axons reveals 75 proteins translationally controlled via the Sema3A-p-eIF2α pathway. These include proteostasis- and actin cytoskeleton-related proteins but not canonical stress markers. Finally, we show that PERK signaling is needed for directional axon migration and visual pathway development in vivo. Thus, our findings reveal a noncanonical eIF2 signaling pathway that controls selective changes in axon translation and is required for neural wiring. eIF2α phosphorylation underlies Sema3A-induced upregulation of global translation pSILAC-SP3 reveals 75 nascent proteins regulated by the Sema3A-p-eIF2α pathway eIF2B modulation is the key node between Sema3A and canonical stress responses PERK signaling is required for axon guidance and neural connectivity
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Affiliation(s)
- Roberta Cagnetta
- Department of Physiology, Development and Neuroscience, Anatomy Building, University of Cambridge, Cambridge CB2 3DY, UK
| | - Hovy Ho-Wai Wong
- Department of Physiology, Development and Neuroscience, Anatomy Building, University of Cambridge, Cambridge CB2 3DY, UK
| | - Christian K Frese
- European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany; German Cancer Research Center (DKFZ), 69121 Heidelberg, Germany; CECAD Research Center, University of Cologne, 50931 Cologne, Germany
| | - Giovanna R Mallucci
- UK Dementia Research Institute and Department of Clinical Neurosciences, Island Research Building, Cambridge Biomedical Campus, University of Cambridge, Cambridge CB2 0SL, UK
| | - Jeroen Krijgsveld
- European Molecular Biology Laboratory (EMBL), 69117 Heidelberg, Germany; German Cancer Research Center (DKFZ), 69121 Heidelberg, Germany
| | - Christine E Holt
- Department of Physiology, Development and Neuroscience, Anatomy Building, University of Cambridge, Cambridge CB2 3DY, UK.
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12
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Sahoo PK, Lee SJ, Jaiswal PB, Alber S, Kar AN, Miller-Randolph S, Taylor EE, Smith T, Singh B, Ho TSY, Urisman A, Chand S, Pena EA, Burlingame AL, Woolf CJ, Fainzilber M, English AW, Twiss JL. Axonal G3BP1 stress granule protein limits axonal mRNA translation and nerve regeneration. Nat Commun 2018; 9:3358. [PMID: 30135423 PMCID: PMC6105716 DOI: 10.1038/s41467-018-05647-x] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 07/12/2018] [Indexed: 12/17/2022] Open
Abstract
Critical functions of intra-axonally synthesized proteins are thought to depend on regulated recruitment of mRNA from storage depots in axons. Here we show that axotomy of mammalian neurons induces translation of stored axonal mRNAs via regulation of the stress granule protein G3BP1, to support regeneration of peripheral nerves. G3BP1 aggregates within peripheral nerve axons in stress granule-like structures that decrease during regeneration, with a commensurate increase in phosphorylated G3BP1. Colocalization of G3BP1 with axonal mRNAs is also correlated with the growth state of the neuron. Disrupting G3BP functions by overexpressing a dominant-negative protein activates intra-axonal mRNA translation, increases axon growth in cultured neurons, disassembles axonal stress granule-like structures, and accelerates rat nerve regeneration in vivo. G3BP1 is RasGAP SH3 domain binding protein 1 that interacts with 48S pre-initiation complex when translation is stalled. Here, Twiss and colleagues show that neuronal G3BP1 can negatively regulate axonal mRNA translation, and inhibit axonal regeneration after injury.
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Affiliation(s)
- Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, 29208, SC, USA
| | - Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, 29208, SC, USA
| | - Poonam B Jaiswal
- Department of Cell Biology, Emory University College of Medicine, Atlanta, 30322, GA, USA
| | - Stefanie Alber
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, 29208, SC, USA
| | | | - Elizabeth E Taylor
- Department of Biological Sciences, University of South Carolina, Columbia, 29208, SC, USA
| | - Terika Smith
- Department of Biological Sciences, University of South Carolina, Columbia, 29208, SC, USA
| | - Bhagat Singh
- FM Kirby Neurobiology Center and Boston Children's Hospital and Harvard Medical School, Boston, 02115, MA, USA
| | - Tammy Szu-Yu Ho
- FM Kirby Neurobiology Center and Boston Children's Hospital and Harvard Medical School, Boston, 02115, MA, USA
| | - Anatoly Urisman
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, 94158, CA, USA
| | - Shreya Chand
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, 94158, CA, USA
| | - Edsel A Pena
- Department of Statistics, University of South Carolina, Columbia, 29208, SC, USA
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, 94158, CA, USA
| | - Clifford J Woolf
- FM Kirby Neurobiology Center and Boston Children's Hospital and Harvard Medical School, Boston, 02115, MA, USA
| | - Mike Fainzilber
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Arthur W English
- Department of Cell Biology, Emory University College of Medicine, Atlanta, 30322, GA, USA
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, 29208, SC, USA.
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13
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Lin YC, Chen CC, Chen WM, Lu KY, Shen TL, Jou YC, Shen CH, Ohbayashi N, Kanaho Y, Huang YL, Lee H. LPA 1/3 signaling mediates tumor lymphangiogenesis through promoting CRT expression in prostate cancer. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:1305-1315. [PMID: 30053596 DOI: 10.1016/j.bbalip.2018.07.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 07/13/2018] [Accepted: 07/20/2018] [Indexed: 12/15/2022]
Abstract
Lysophosphatidic acid (LPA) is a bioactive lipid growth factor which is present in high levels in serum and platelets. LPA binds to its specific G-protein-coupled receptors, including LPA1 to LPA6, thereby regulating various physiological functions, including cancer growth, angiogenesis, and lymphangiogenesis. Our previous study showed that LPA promotes the expression of the lymphangiogenic factor vascular endothelial growth factor (VEGF)-C in prostate cancer (PCa) cells. Interestingly, LPA has been shown to regulate the expression of calreticulin (CRT), a multifunctional chaperone protein, but the roles of CRT in PCa progression remain unclear. Here we investigated the involvement of CRT in LPA-mediated VEGF-C expression and lymphangiogenesis in PCa. Knockdown of CRT significantly reduced LPA-induced VEGF-C expression in PC-3 cells. Moreover, LPA promoted CRT expression through LPA receptors LPA1 and LPA3, reactive oxygen species (ROS) production, and phosphorylation of eukaryotic translation initiation factor 2α (eIF2α). Tumor-xenografted mouse experiments further showed that CRT knockdown suppressed tumor growth and lymphangiogenesis. Notably, clinical evidence indicated that the LPA-producing enzyme autotaxin (ATX) is related to CRT and that CRT level is highly associated with lymphatic vessel density and VEGF-C expression. Interestingly, the pharmacological antagonist of LPA receptors significantly reduced the lymphatic vessel density in tumor and lymph node metastasis in tumor-bearing nude mice. Together, our results demonstrated that CRT is critical in PCa progression through the mediation of LPA-induced VEGF-C expression, implying that targeting the LPA signaling axis is a potential therapeutic strategy for PCa.
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Affiliation(s)
- Yueh-Chien Lin
- Department of Life Sciences, National Taiwan University, Taipei 10617, Taiwan; Department of Physiological Chemistry, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Chien-Chin Chen
- Department of Pathology, Chia-Yi Christian Hospital, Chiayi 600, Taiwan; Department of Cosmetic Science, Chia Nan University of Pharmacy and Science, Tainan 71710, Taiwan
| | - Wei-Min Chen
- Department of Life Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Kuan-Ying Lu
- Department of Life Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Tang-Long Shen
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei 10617, Taiwan
| | - Yeong-Chin Jou
- Department of Urology, Chia-Yi Christian Hospital, Chiayi 600, Taiwan
| | - Cheng-Huang Shen
- Department of Urology, Chia-Yi Christian Hospital, Chiayi 600, Taiwan
| | - Norihiko Ohbayashi
- Department of Physiological Chemistry, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Yasunori Kanaho
- Department of Physiological Chemistry, Faculty of Medicine and Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8575, Japan
| | - Yuan-Li Huang
- Department of Biotechnology, Asia University, Taichung 41354, Taiwan; Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 40402, Taiwan.
| | - Hsinyu Lee
- Department of Life Sciences, National Taiwan University, Taipei 10617, Taiwan; Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan; Institute of Biomedical Electronic and Bioinformatics, National Taiwan University, Taipei 10617, Taiwan; Center for Biotechnology, National Taiwan University, Taipei 10617, Taiwan.
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14
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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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15
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Phay M, Kim HH, Yoo S. Analysis of piRNA-Like Small Non-coding RNAs Present in Axons of Adult Sensory Neurons. Mol Neurobiol 2016; 55:483-494. [PMID: 27966078 DOI: 10.1007/s12035-016-0340-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 12/02/2016] [Indexed: 10/20/2022]
Abstract
Small non-coding RNAs (sncRNAs) have been shown to play pivotal roles in spatiotemporal-specific gene regulation that is linked to many different biological functions. PIWI-interacting RNAs (piRNAs), typically 25-34-nucleotide long, are originally identified and thought to be restricted in germline cells. However, recent studies suggest that piRNAs associate with neuronal PIWI proteins, contributing to neuronal development and function. Here, we identify a cohort of piRNA-like sncRNAs (piLRNAs) in rat sciatic nerve axoplasm and directly contrast temporal changes of piLRNA levels in the nerve following injury, as compared with those in an uninjured nerve using deep sequencing. We find that 32 of a total of 53 annotated piLRNAs show significant changes in their levels in the regenerating nerve, suggesting that individual axonal piLRNAs may play important regulatory roles in local messenger RNA (mRNA) translation during regeneration. Bioinformatics and biochemical analyses show that these piLRNAs carry characteristic features of mammalian piRNAs, including sizes, a sequence bias for uracil at the 5'-end and a 2'-O-methylation at the 3'-end. Their axonal expression is directly visualized by fluorescence in situ hybridization in cultured dorsal root ganglion neurons as well as immunoprecipitation with MIWI. Further, depletion of MIWI protein using RNAi from cultured sensory neurons increases axon growth rates, decreases axon retraction after injury, and increases axon regrowth after injury. All these data suggest more general roles for MIWI/piLRNA pathway that could confer a unique advantage for coordinately altering the population of proteins generated in growth cones and axons of neurons by targeting mRNA cohorts.
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Affiliation(s)
- Monichan Phay
- Nemours Biomedical Research, Alfred I duPont Hospital for Children, Wilmington, DE, 19803, USA.,Department of Biological Sciences, University of Delaware, Newark, DE, 19716, USA
| | - Hak Hee Kim
- Nemours Biomedical Research, Alfred I duPont Hospital for Children, Wilmington, DE, 19803, USA
| | - Soonmoon Yoo
- Nemours Biomedical Research, Alfred I duPont Hospital for Children, Wilmington, DE, 19803, USA. .,Department of Biological Sciences, University of Delaware, Newark, DE, 19716, USA.
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16
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Dynamic Changes in Local Protein Synthetic Machinery in Regenerating Central Nervous System Axons after Spinal Cord Injury. Neural Plast 2016; 2016:4087254. [PMID: 27375904 PMCID: PMC4914735 DOI: 10.1155/2016/4087254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 04/19/2016] [Accepted: 05/10/2016] [Indexed: 01/23/2023] Open
Abstract
Intra-axonal localization of mRNAs and protein synthesis machinery (PSM) endows neurons with the capacity to generate proteins locally, allowing precise spatiotemporal regulation of the axonal response to extracellular stimuli. A number of studies suggest that this local translation is a promising target to enhance the regenerative capacity of damaged axons. Using a model of central nervous system (CNS) axons regenerating into intraspinal peripheral nerve grafts (PNGs) we established that adult regenerating CNS axons contain several different mRNAs and protein synthetic machinery (PSM) components in vivo. After lower thoracic level spinal cord transection, ascending sensory axons regenerate into intraspinal PNGs but axon growth is stalled when they reach the distal end of the PNG (3 versus 7 weeks after grafting, resp.). By immunofluorescence with optical sectioning of axons by confocal microscopy, the total and phosphorylated forms of PSMs are significantly lower in stalled compared with actively regenerating axons. Reinjury of these stalled axons increased axonal localization of the PSM proteins, indicative of possible priming for a subcellular response to axotomy. These results suggest that axons downregulate protein synthetic capacity as they cease growing, yet they retain the ability to upregulate PSM after a second injury.
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17
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The Unfolded Protein Response and Cholesterol Biosynthesis Link Luman/CREB3 to Regenerative Axon Growth in Sensory Neurons. J Neurosci 2016; 35:14557-70. [PMID: 26511246 DOI: 10.1523/jneurosci.0012-15.2015] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
We recently revealed that the axon endoplasmic reticulum resident transcription factor Luman/CREB3 (herein called Luman) serves as a unique retrograde injury signal in regulation of the intrinsic elongating form of sensory axon regeneration. Here, evidence supports that Luman contributes to axonal regeneration through regulation of the unfolded protein response (UPR) and cholesterol biosynthesis in adult rat sensory neurons. One day sciatic nerve crush injury triggered a robust increase in UPR-associated mRNA and protein expression in both neuronal cell bodies and the injured axons. Knockdown of Luman expression in 1 d injury-conditioned neurons by siRNA attenuated axonal outgrowth to 48% of control injured neurons and was concomitant with reduced UPR- and cholesterol biosynthesis-associated gene expression. UPR PCR-array analysis coupled with qRT-PCR identified and confirmed that four transcripts involved in cholesterol regulation were downregulated >2-fold by the Luman siRNA treatment of the injury-conditioned neurons. Further, the Luman siRNA-attenuated outgrowth could be significantly rescued by either cholesterol supplementation or 2 ng/ml of the UPR inducer tunicamycin, an amount determined to elevate the depressed UPR gene expression to a level equivalent of that observed with crush injury. Using these approaches, outgrowth increased significantly to 74% or 69% that of injury-conditioned controls, respectively. The identification of Luman as a regulator of the injury-induced UPR and cholesterol at levels that benefit the intrinsic ability of axotomized adult rat sensory neurons to undergo axonal regeneration reveals new therapeutic targets to bolster nerve repair.
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18
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Hsu WL, Chung HW, Wu CY, Wu HI, Lee YT, Chen EC, Fang W, Chang YC. Glutamate Stimulates Local Protein Synthesis in the Axons of Rat Cortical Neurons by Activating α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptors and Metabotropic Glutamate Receptors. J Biol Chem 2015; 290:20748-20760. [PMID: 26134564 DOI: 10.1074/jbc.m115.638023] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Indexed: 12/20/2022] Open
Abstract
Glutamate is the principal excitatory neurotransmitter in the mammalian CNS. By analyzing the metabolic incorporation of azidohomoalanine, a methionine analogue, in newly synthesized proteins, we find that glutamate treatments up-regulate protein translation not only in intact rat cortical neurons in culture but also in the axons emitting from cortical neurons before making synapses with target cells. The process by which glutamate stimulates local translation in axons begins with the binding of glutamate to the ionotropic AMPA receptors and metabotropic glutamate receptor 1 and members of group 2 metabotropic glutamate receptors on the plasma membrane. Subsequently, the activated mammalian target of rapamycin (mTOR) signaling pathway and the rise in Ca(2+), resulting from Ca(2+) influxes through calcium-permeable AMPA receptors, voltage-gated Ca(2+) channels, and transient receptor potential canonical channels, in axons stimulate the local translation machinery. For comparison, the enhancement effects of brain-derived neurotrophic factor (BDNF) on the local protein synthesis in cortical axons were also studied. The results indicate that Ca(2+) influxes via transient receptor potential canonical channels and activated the mTOR pathway in axons also mediate BDNF stimulation to local protein synthesis. However, glutamate- and BDNF-induced enhancements of translation in axons exhibit different kinetics. Moreover, Ca(2+) and mTOR signaling appear to play roles carrying different weights, respectively, in transducing glutamate- and BDNF-induced enhancements of axonal translation. Thus, our results indicate that exposure to transient increases of glutamate and more lasting increases of BDNF would stimulate local protein synthesis in migrating axons en route to their targets in the developing brain.
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Affiliation(s)
- Wei-Lun Hsu
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Hui-Wen Chung
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Chih-Yueh Wu
- Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Huei-Ing Wu
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Yu-Tao Lee
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
| | - En-Chan Chen
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Weilun Fang
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
| | - Yen-Chung Chang
- Institute of Molecular Medicine, National Tsing Hua University, Hsinchu 300, Taiwan; Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu 300, Taiwan; Institute of Nanoengineering and Microsystems, National Tsing Hua University, Hsinchu 300, Taiwan.
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19
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Kim HH, Kim P, Phay M, Yoo S. Identification of precursor microRNAs within distal axons of sensory neuron. J Neurochem 2015; 134:193-9. [PMID: 25919946 DOI: 10.1111/jnc.13140] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/09/2015] [Accepted: 04/10/2015] [Indexed: 11/30/2022]
Abstract
A set of specific precursor microRNAs (pre-miRNAs) are reported to localize into neuronal dendrites, where they could be processed locally to control synaptic protein synthesis and plasticity. However, it is not clear whether specific pre-miRNAs are also transported into distal axons to autonomously regulate intra-axonal protein synthesis. Here, we show that a subset of pre-miRNAs, whose mature miRNAs are enriched in axonal compartment of sympathetic neurons, are present in axons of neurons both in vivo and in vitro by quantitative PCR and by in situ hybridization. Some pre-miRNAs (let 7c-a and pre-miRs-16, 23a, 25, 125b-1, 433, and 541) showed elevated axonal levels, while others (pre-miRs-138-2, 185, and 221) were decreased in axonal levels following injury. Dicer and KSRP proteins are also present in distal axons, but Drosha is found restricted to the cell body. These findings suggest that specific pre-miRNAs are selected for localization into distal axons of sensory neurons and are presumably processed to mature miRNAs in response to extracellular stimuli. This study supports the notion that local miRNA biogenesis effectively provides another level of temporal control for local protein synthesis in axons.
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Affiliation(s)
- Hak Hee Kim
- Nemours Biomedical Research, Alfred I. DuPont Hospital for Children, Wilmington, Delaware, USA
| | - Paul Kim
- Nemours Biomedical Research, Alfred I. DuPont Hospital for Children, Wilmington, Delaware, USA
| | - Monichan Phay
- Nemours Biomedical Research, Alfred I. DuPont Hospital for Children, Wilmington, Delaware, USA.,Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
| | - Soonmoon Yoo
- Nemours Biomedical Research, Alfred I. DuPont Hospital for Children, Wilmington, Delaware, USA
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20
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French AS, Li AW, Meisner S, Torkkeli PH. Upstream open reading frames and Kozak regions of assembled transcriptome sequences from the spider Cupiennius salei. Selection or chance? Gene 2014; 539:203-8. [PMID: 24530309 DOI: 10.1016/j.gene.2014.01.079] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 01/24/2014] [Accepted: 01/31/2014] [Indexed: 11/28/2022]
Abstract
We assembled a new set of mRNA sequences from the leg hypodermis transcriptome of the wandering spider, Cupiennius salei. Each sequence was assembled to exhaustion in the 5' direction to detect all upstream open reading frames (uORFs) both in-frame and out-of-frame with the main open reading frame (mORF). We also counted nucleotide probabilities before and after the START codon of the mORF to establish the optimum Kozak consensus sequence. More than 80% of 5' sequences had uORFs before the mORF with a range of 1-16 uORFs. Kozak consensus strengths of uORFs were significantly weaker than mORFs. Random scrambling of 5' nucleotide positions did not give significantly different numbers, sizes, or Kozak consensus strengths of uORFs. Random simulations of 5' sequences using either equal or experimental distributions of nucleotides gave similar numbers of uORFs, with similar sizes and Kozak consensus strengths to experimental data. Abundance of mRNA for each gene was estimated by counting matching Illumina reads to assembled genes. Abundance was negatively correlated with numbers of uORFs, but not with 5' length. Our data are compatible with a random model of 5' mRNA sequence structure.
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Affiliation(s)
- Andrew S French
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada.
| | - Audrey W Li
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Shannon Meisner
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Päivi H Torkkeli
- Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada
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21
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Li S, Yang L, Selzer ME, Hu Y. Neuronal endoplasmic reticulum stress in axon injury and neurodegeneration. Ann Neurol 2013; 74:768-77. [PMID: 23955583 PMCID: PMC3963272 DOI: 10.1002/ana.24005] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 08/04/2013] [Accepted: 08/07/2013] [Indexed: 12/13/2022]
Abstract
Injuries to central nervous system axons result not only in Wallerian degeneration of the axon distal to the injury, but also in death or atrophy of the axotomized neurons, depending on injury location and neuron type. No method of permanently avoiding these changes has been found, despite extensive knowledge concerning mechanisms of secondary neuronal injury. The autonomous endoplasmic reticulum (ER) stress pathway in neurons has recently been implicated in retrograde neuronal degeneration. In addition to the emerging role of ER morphology in axon maintenance, we propose that ER stress is a common neuronal response to disturbances in axon integrity and a general mechanism for neurodegeneration. Thus, manipulation of the ER stress pathway could have important therapeutic implications for neuroprotection.
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Affiliation(s)
- Shaohua Li
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Temple University School of Medicine, Philadelphia, PA, USA
- Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, China
| | - Liu Yang
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Temple University School of Medicine, Philadelphia, PA, USA
| | - Michael E. Selzer
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Temple University School of Medicine, Philadelphia, PA, USA
- Department of Neurology, Temple University School of Medicine, Philadelphia, PA, USA
| | - Yang Hu
- Shriners Hospitals Pediatric Research Center (Center for Neural Repair and Rehabilitation), Temple University School of Medicine, Philadelphia, PA, USA
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22
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Axonal localization of neuritin/CPG15 mRNA in neuronal populations through distinct 5' and 3' UTR elements. J Neurosci 2013; 33:13735-42. [PMID: 23966695 DOI: 10.1523/jneurosci.0962-13.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Many neuronal mRNAs are actively transported into distal axons. The 3' untranslated regions (UTRs) of axonal mRNAs often contain cues for their localization. The 3' UTR of neuritin mRNA was shown to be sufficient for localization into axons of hippocampal neurons. Here, we show that neuritin mRNA localizes into axons of rat sensory neurons, but this is predominantly driven by the 5' rather than 3' UTR. Neuritin mRNA shifts from cell body to axon predominantly after nerve crush injury, suggesting that it encodes a growth-associated protein. Consistent with this, overexpression of neuritin increases axon growth but only when its mRNA localizes into the axons.
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23
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Peripheral nerve axons contain machinery for co-translational secretion of axonally-generated proteins. Neurosci Bull 2013; 29:493-500. [PMID: 23839054 DOI: 10.1007/s12264-013-1360-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 05/19/2013] [Indexed: 10/26/2022] Open
Abstract
The axonal compartment of developing neurons and mature peripheral nervous system (PNS) neurons has the capacity to locally synthesize proteins. Axonally-synthesized proteins have been shown to facilitate axonal pathfinding and maintenance in developing central nervous system (CNS) and PNS neurons, and to facilitate the regeneration of mature PNS neurons. RNA-profiling studies of the axons of cultured neurons have shown a surprisingly complex population of mRNAs that encode proteins for a myriad of functions. Although classic-appearing rough endoplasmic reticulum (RER), smooth endoplasmic reticulum (ER) and Golgi apparatus have not been documented in axons by ultrastructural studies, axonal RNA profiling studies show several membrane and secreted protein-encoding mRNAs whose translation products would need access to a localized secretory mechanism. We previously showed that the axons of cultured neurons contain functional equivalents of RER and Golgi apparatus. Here, we show that markers for the signal-recognition particle, RER, ER, and Golgi apparatus are present in PNS axons in vivo. Co-localization of these proteins mirrors that seen for cultured axons where locally-translated proteins are localized to the axoplasmic membrane. Moreover, nerve injury increases the levels and/or aggregation of these proteins, suggesting that the regenerating axon has an increased capacity for membrane targeting of locally synthesized proteins.
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24
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Yoo S, Kim HH, Kim P, Donnelly CJ, Kalinski AL, Vuppalanchi D, Park M, Lee SJ, Merianda TT, Perrone-Bizzozero NI, Twiss JL. A HuD-ZBP1 ribonucleoprotein complex localizes GAP-43 mRNA into axons through its 3' untranslated region AU-rich regulatory element. J Neurochem 2013; 126:792-804. [PMID: 23586486 DOI: 10.1111/jnc.12266] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 04/01/2013] [Accepted: 04/01/2013] [Indexed: 11/29/2022]
Abstract
Localized translation of axonal mRNAs contributes to developmental and regenerative axon growth. Although untranslated regions (UTRs) of many different axonal mRNAs appear to drive their localization, there has been no consensus RNA structure responsible for this localization. We recently showed that limited expression of ZBP1 protein restricts axonal localization of both β-actin and GAP-43 mRNAs. β-actin 3'UTR has a defined element for interaction with ZBP1, but GAP-43 mRNA shows no homology to this RNA sequence. Here, we show that an AU-rich regulatory element (ARE) in GAP-43's 3'UTR is necessary and sufficient for its axonal localization. Axonal GAP-43 mRNA levels increase after in vivo injury, and GAP-43 mRNA shows an increased half-life in regenerating axons. GAP-43 mRNA interacts with both HuD and ZBP1, and HuD and ZBP1 co-immunoprecipitate in an RNA-dependent fashion. Reporter mRNA with the GAP-43 ARE competes with endogenous β-actin mRNA for axonal localization and decreases axon length and branching similar to the β-actin 3'UTR competing with endogenous GAP-43 mRNA. Conversely, over-expressing GAP-43 coding sequence with its 3'UTR ARE increases axonal elongation and this effect is lost when just the ARE is deleted from GAP-43's 3'UTR. We have recently found that over-expression of GAP-43 using an axonally targeted construct with the 3'UTRs of GAP-43 promoted elongating growth of axons, while restricting the mRNA to the cell body with the 3'UTR of γ-actin had minimal effect on axon length. In this study, we show that the ARE in GAP-43's 3'UTR is responsible for localization of GAP-43 mRNA into axons and is sufficient for GAP-43 protein's role in elongating axonal growth.
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Affiliation(s)
- Soonmoon Yoo
- Nemours Biomedical Research, Alfred I. duPont Hosp. for Children, Wilmington, Delaware, USA.
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Merianda TT, Vuppalanchi D, Yoo S, Blesch A, Twiss JL. Axonal transport of neural membrane protein 35 mRNA increases axon growth. J Cell Sci 2012; 126:90-102. [PMID: 23097042 DOI: 10.1242/jcs.107268] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many neuronal mRNAs are transported from cell bodies into axons and dendrites. Localized translation of the mRNAs brings autonomy to these processes that can be vast distances from the cell body. For axons, these translational responses have been linked to growth and injury signaling, but there has been little information about local function of individual axonally synthesized proteins. In the present study, we show that axonal injury increases levels of the mRNA encoding neural membrane protein 35 (NMP35) in axons, with a commensurate decrease in the cell body levels of NMP35 mRNA. The 3' untranslated region (3'UTR) of NMP35 is responsible for this localization into axons. Previous studies have shown that NMP35 protein supports cell survival by inhibiting Fas-ligand-mediated apoptosis; however, these investigations did not distinguish functions of the locally generated NMP35 protein. Using axonally targeted versus cell-body-restricted NMP35 constructs, we show that NMP35 supports axonal growth, and overexpression of an axonally targeted NMP35 mRNA is sufficient to increase axonal outgrowth.
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Affiliation(s)
- Tanuja T Merianda
- Department of Biology, Drexel University, Philadelphia, PA 19104, USA
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Pacheco A, Twiss JL. Localized IRES-dependent translation of ER chaperone protein mRNA in sensory axons. PLoS One 2012; 7:e40788. [PMID: 22911708 PMCID: PMC3404055 DOI: 10.1371/journal.pone.0040788] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Accepted: 06/13/2012] [Indexed: 12/25/2022] Open
Abstract
Transport of neuronal mRNAs into distal nerve terminals and growth cones allows axonal processes to generate proteins autonomous from the cell body. While the mechanisms for targeting mRNAs for transport into axons has received much attention, how specificity is provided to the localized translational apparatus remains largely unknown. In other cellular systems, protein synthesis can be regulated by both cap-dependent and cap-independent mechanisms. The possibility that these mechanisms are used by axons has not been tested. Here, we have used expression constructs encoding axonally targeted bicistronic reporter mRNAs to determine if sensory axons can translate mRNAs through cap-independent mechanisms. Our data show that the well-defined IRES element of encephalomyocarditis virus (EMCV) can drive internal translational initiation of a bicistronic reporter mRNA in distal DRG axons. To test the potential for cap-independent translation of cellular mRNAs, we asked if calreticulin or grp78/BiP mRNA 5'UTRs might have IRES activity in axons. Only grp78/BiP mRNA 5'UTR showed clear IRES activity in axons when placed between the open reading frames of diffusion limited fluorescent reporters. Indeed, calreticulin's 5'UTR provided an excellent control for potential read through by ribosomes, since there was no evidence of internal initiation when this UTR was placed between reporter ORFs in a bicistronic mRNA. This study shows that axons have the capacity to translate through internal ribosome entry sites, but a simple binary choice between cap-dependent and cap-independent translation cannot explain the specificity for translation of individual mRNAs in distal axons.
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Affiliation(s)
- Almudena Pacheco
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Jeffery L. Twiss
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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