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Wang J, Li Y, Struebing FL, Jardines S, Lin ST, Lin F, Geisert EE. Dnajc3 (HSP40) Modulates Axon Regeneration in the Mouse Optic Nerve. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.10.08.617251. [PMID: 39416210 PMCID: PMC11482814 DOI: 10.1101/2024.10.08.617251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2024]
Abstract
Background The present study is designed to identify the genes modulating optic nerve regeneration in the mouse. Using the BXD mouse strains as a genetic mapping panel, we examined differential responses to axon regeneration in order to map genomic loci modulating axonal regeneration. Methods To study regeneration in the optic nerve, Pten was knocked down in the retinal ganglion cells using adeno-associated virus (AAV) delivery of an shRNA, followed by the induction of a mild inflammatory response by an intravitreal injection of Zymosan with CPT-cAMP. The axons of the retinal ganglion cells were damaged by optic nerve crush (ONC). Following a 12-day survival period, regenerating axons were labeled by Cholera Toxin B. Two days later, the regenerating axons within the optic nerve were examined to determine the number of regenerating axons and the distance traveled down the optic nerve. An integral genomic map was made using the regenerative response. Candidate genes were tested by knocking down expression using shRNA or by overexpressing the gene in AAV vectors. Results The analysis revealed a considerable amount of differential axonal regeneration across all 33 BXD strains, demonstrated by the number of axons regenerating and the length of the regenerating axons. Some strains (BXD99, BXD90, and BXD29) demonstrated significant axonal regeneration; while other strains (BXD13, BXD18, and BXD34) had very little axon regrowth. Within the regenerative data, there was a 4-fold increase in distance regenerated and a 7.5-fold difference in the number of regenerating axons. These data were used to map a quantitative trait locus modulating axonal regeneration to Chromosome 14 (115 to 119 Mb). Within this locus were 16 annotated genes. Subsequent testing revealed that one candidate gene, Dnajc3 , modulates axonal regeneration. Knocking down of Dnajc3 led to a decreased regeneration response in the high regenerative strains (BXD90), while overexpression of Dnajc3 resulted in an increased regeneration response in C57BL/6J and a low regenerative strain (BXD34). Conclusion In this study, Dnajc3 (encodes Heat Shock Protein 40, HSP40, a molecular chaperone) was identified as a modulator of axon regeneration in mice. This is the first report defining the role of Dnajc3 (HSP40) in axon regeneration.
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Sahoo PK, Hanovice N, Ward P, Agrawal M, Smith TP, SiMa H, Dulin JN, Vaughn LS, Tuszynski M, Welshhans K, Benowitz L, English A, Houle JD, Twiss JL. Disruption of Core Stress Granule Protein Aggregates Promotes CNS Axon Regeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.07.597743. [PMID: 38895344 PMCID: PMC11185597 DOI: 10.1101/2024.06.07.597743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Depletion or inhibition of core stress granule proteins, G3BP1 in mammals and TIAR-2 in C. elegans , increases axon regeneration in injured neurons that show spontaneous regeneration. Inhibition of G3BP1 by expression of its acidic or 'B-domain' accelerates axon regeneration after nerve injury bringing a potential therapeutic intervention to promote neural repair in the peripheral nervous system. Here, we asked if G3BP1 inhibition is a viable strategy to promote regeneration in the injured mammalian central nervous system where axons do not regenerate spontaneously. G3BP1 B-domain expression was found to promote axon regeneration in both the mammalian spinal cord and optic nerve. Moreover, a cell permeable peptide to a subregion of G3BP1's B-domain (rodent G3BP1 amino acids 190-208) accelerated axon regeneration after peripheral nerve injury and promoted the regrowth of reticulospinal axons into the distal transected spinal cord through a bridging peripheral nerve graft. The rodent and human G3BP1 peptides promoted axon growth from rodent and human neurons cultured on permissive substrates, and this function required alternating Glu/Asp-Pro repeats that impart a unique predicted tertiary structure. These studies point to G3BP1 granules as a critical impediment to CNS axon regeneration and indicate that G3BP1 granule disassembly represents a novel therapeutic strategy for promoting neural repair after CNS injury.
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Kvistad CE, Kråkenes T, Gavasso S, Bø L. Neural regeneration in the human central nervous system-from understanding the underlying mechanisms to developing treatments. Where do we stand today? Front Neurol 2024; 15:1398089. [PMID: 38803647 PMCID: PMC11129638 DOI: 10.3389/fneur.2024.1398089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 04/22/2024] [Indexed: 05/29/2024] Open
Abstract
Mature neurons in the human central nervous system (CNS) fail to regenerate after injuries. This is a common denominator across different aetiologies, including multiple sclerosis, spinal cord injury and ischemic stroke. The lack of regeneration leads to permanent functional deficits with a substantial impact on patient quality of life, representing a significant socioeconomic burden worldwide. Great efforts have been made to decipher the responsible mechanisms and we now know that potent intra- and extracellular barriers prevent axonal repair. This knowledge has resulted in numerous clinical trials, aiming to promote neuroregeneration through different approaches. Here, we summarize the current understanding of the causes to the poor regeneration within the human CNS. We also review the results of the treatment attempts that have been translated into clinical trials so far.
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Affiliation(s)
| | - Torbjørn Kråkenes
- Neuro-SysMed, Department of Neurology, Haukeland University Hospital, Bergen, Norway
| | - Sonia Gavasso
- Neuro-SysMed, Department of Neurology, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Lars Bø
- Neuro-SysMed, Department of Neurology, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
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Jara JS, Avci HX, Kouremenou I, Doulazmi M, Bakouche J, Dubacq C, Goyenvalle C, Mariani J, Lohof AM, Sherrard RM. Pax3 induces target-specific reinnervation through axon collateral expression of PSA-NCAM. Prog Neurobiol 2024; 232:102560. [PMID: 38097036 DOI: 10.1016/j.pneurobio.2023.102560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 11/07/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023]
Abstract
Damaged or dysfunctional neural circuits can be replaced after a lesion by axon sprouting and collateral growth from undamaged neurons. Unfortunately, these new connections are often disorganized and rarely produce clinical improvement. Here we investigate how to promote post-lesion axonal collateral growth, while retaining correct cellular targeting. In the mouse olivocerebellar path, brain-derived neurotrophic factor (BDNF) induces correctly-targeted post-lesion cerebellar reinnervation by remaining intact inferior olivary axons (climbing fibers). In this study we identified cellular processes through which BDNF induces this repair. BDNF injection into the denervated cerebellum upregulates the transcription factor Pax3 in inferior olivary neurons and induces rapid climbing fiber sprouting. Pax3 in turn increases polysialic acid-neural cell adhesion molecule (PSA-NCAM) in the sprouting climbing fiber path, facilitating collateral outgrowth and pathfinding to reinnervate the correct targets, cerebellar Purkinje cells. BDNF-induced reinnervation can be reproduced by olivary Pax3 overexpression, and abolished by olivary Pax3 knockdown, suggesting that Pax3 promotes axon growth and guidance through upregulating PSA-NCAM, probably on the axon's growth cone. These data indicate that restricting growth-promotion to potential reinnervating afferent neurons, as opposed to stimulating the whole circuit or the injury site, allows axon growth and appropriate guidance, thus accurately rebuilding a neural circuit.
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Affiliation(s)
- J Sebastian Jara
- Sorbonne Université & CNRS, IBPS-B2A, Biological Adaptation and Ageing, Paris France
| | - Hasan X Avci
- Sorbonne Université & CNRS, IBPS-B2A, Biological Adaptation and Ageing, Paris France
| | - Ioanna Kouremenou
- Sorbonne Université & CNRS, IBPS-B2A, Biological Adaptation and Ageing, Paris France
| | - Mohamed Doulazmi
- Sorbonne Université & CNRS, IBPS-B2A, Biological Adaptation and Ageing, Paris France
| | - Joelle Bakouche
- Sorbonne Université & CNRS, IBPS-B2A, Biological Adaptation and Ageing, Paris France
| | - Caroline Dubacq
- Sorbonne Université, CNRS & INSERM, IBPS-NPS, Neurosciences Paris Seine, Paris France
| | - Catherine Goyenvalle
- Sorbonne Université & CNRS, IBPS-B2A, Biological Adaptation and Ageing, Paris France
| | - Jean Mariani
- Sorbonne Université & CNRS, IBPS-B2A, Biological Adaptation and Ageing, Paris France
| | - Ann M Lohof
- Sorbonne Université & CNRS, IBPS-B2A, Biological Adaptation and Ageing, Paris France
| | - Rachel M Sherrard
- Sorbonne Université & CNRS, IBPS-B2A, Biological Adaptation and Ageing, Paris France.
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Carew JA, Cristofaro V, Goyal RK, Sullivan MP. Differential Myosin 5a splice variants in innervation of pelvic organs. Front Physiol 2023; 14:1304537. [PMID: 38148903 PMCID: PMC10749955 DOI: 10.3389/fphys.2023.1304537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 11/20/2023] [Indexed: 12/28/2023] Open
Abstract
Introduction: Myosin proteins interact with filamentous actin and translate the chemical energy generated by ATP hydrolysis into a wide variety of mechanical functions in all cell types. The classic function of conventional myosins is mediation of muscle contraction, but myosins also participate in processes as diverse as exocytosis/endocytosis, membrane remodeling, and cytokinesis. Myosin 5a (Myo5a) is an unconventional motor protein well-suited to the processive transport of diverse molecular cargo within cells and interactions with multiprotein membrane complexes that facilitate exocytosis. Myo5a includes a region consisting of six small alternative exons which can undergo differential splicing. Neurons and skin melanocytes express characteristic splice variants of Myo5a, which are specialized for transport processes unique to those cell types. But less is known about the expression of Myo5a splice variants in other tissues, their cargos and interactive partners, and their regulation. Methods: In visceral organs, neurotransmission-induced contraction or relaxation of smooth muscle is mediated by Myo5a. Axons within urogenital organs and distal colon of rodents arise from cell bodies located in the major pelvic ganglion (MPG). However, in contrast to urogenital organs, the distal colon also contains soma of the enteric nervous system. Therefore, the rodent pelvic organs provide an opportunity to compare the expression of Myo5a splice variants, not only in different tissues innervated by the pelvic nerves, but also in different subcellular compartments of those nerves. This study examines the expression and distribution of Myo5a splice variants in the MPG, compared to the bladder, corpus cavernosum of the penis (CCP) and distal colon using immunohistochemistry and mRNA analyses. Results/discussion: We report detection of characteristic Myo5a variants in these tissues, with bladder and CCP displaying a similar variant pattern but one which differed from that of distal colon. In all three organs, Myo5a variants were distinct compared to the MPG, implying segregation of one variant within nerve soma and its exclusion from axons. The expression of distinct Myo5a variant arrays is likely to be adaptive, and to underlie specific functions fulfilled by Myo5a in those particular locations.
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Affiliation(s)
- Josephine A. Carew
- Urology Research, VA Boston Healthcare System, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
- Department of Medicine, Brigham and Women’s Hospital, Boston, MA, United States
| | - Vivian Cristofaro
- Urology Research, VA Boston Healthcare System, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
- Department of Surgery, Brigham and Women’s Hospital, Boston, MA, United States
| | - Raj K. Goyal
- Urology Research, VA Boston Healthcare System, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
| | - Maryrose P. Sullivan
- Urology Research, VA Boston Healthcare System, Boston, MA, United States
- Harvard Medical School, Boston, MA, United States
- Department of Surgery, Brigham and Women’s Hospital, Boston, MA, United States
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Xing J, Theune WC, Lukomska A, Frost MP, Damania A, Trakhtenberg EF. Experimental upregulation of developmentally downregulated ribosomal protein large subunits 7 and 7A promotes axon regeneration after injury in vivo. Exp Neurol 2023; 368:114510. [PMID: 37633482 PMCID: PMC10529763 DOI: 10.1016/j.expneurol.2023.114510] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 08/08/2023] [Accepted: 08/23/2023] [Indexed: 08/28/2023]
Abstract
Ribosomal proteins are involved in neurodevelopment and central nervous system (CNS) disease and injury. However, the roles of specific ribosomal protein subunits in developmental axon growth, and their potential as therapeutic targets for treating CNS injuries, are still poorly understood. Here, we show that ribosomal protein large (Rpl) and small (Rps) subunit genes are substantially (56-fold) enriched amongst the genes, which are downregulated during maturation of retinal ganglion cell (RGC) CNS projection neurons. We also show that Rpl and Rps subunits are highly co-regulated in RGCs, and partially re-upregulated after optic nerve crush (ONC). Because developmental downregulation of ribosomal proteins coincides with developmental decline in neuronal intrinsic axon growth capacity, we hypothesized that Rpl/Rps incomplete re-upregulation after injury may be a part of the cellular response which attempts to reactivate intrinsic axon growth mechanisms. We found that experimentally upregulating Rpl7 and Rpl7A promoted axon regeneration after ONC in vivo. Finally, we characterized gene networks associated with Rpl/Rps, and showed that Rpl7 and Rpl7A belong to the cluster of genes, which are shared between translational and neurodevelopmental biological processes (based on gene-ontology) that are co-downregulated in maturing RGCs during the decline in intrinsic axon growth capacity.
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Affiliation(s)
- Jian Xing
- Department of Neuroscience, University of Connecticut School of Medicine, 263 Farmington Ave, Farmington, CT 06030, USA
| | - William C Theune
- Department of Neuroscience, University of Connecticut School of Medicine, 263 Farmington Ave, Farmington, CT 06030, USA
| | - Agnieszka Lukomska
- Department of Neuroscience, University of Connecticut School of Medicine, 263 Farmington Ave, Farmington, CT 06030, USA
| | - Matthew P Frost
- Department of Neuroscience, University of Connecticut School of Medicine, 263 Farmington Ave, Farmington, CT 06030, USA
| | - Ashiti Damania
- Department of Neuroscience, University of Connecticut School of Medicine, 263 Farmington Ave, Farmington, CT 06030, USA
| | - Ephraim F Trakhtenberg
- Department of Neuroscience, University of Connecticut School of Medicine, 263 Farmington Ave, Farmington, CT 06030, USA.
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Pinho-Correia LM, Prokop A. Maintaining essential microtubule bundles in meter-long axons: a role for local tubulin biogenesis? Brain Res Bull 2023; 193:131-145. [PMID: 36535305 DOI: 10.1016/j.brainresbull.2022.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 12/12/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022]
Abstract
Axons are the narrow, up-to-meter long cellular processes of neurons that form the biological cables wiring our nervous system. Most axons must survive for an organism's lifetime, i.e. up to a century in humans. Axonal maintenance depends on loose bundles of microtubules that run without interruption all along axons. The continued turn-over and the extension of microtubule bundles during developmental, regenerative or plastic growth requires the availability of α/β-tubulin heterodimers up to a meter away from the cell body. The underlying regulation in axons is poorly understood and hardly features in past and contemporary research. Here we discuss potential mechanisms, particularly focussing on the possibility of local tubulin biogenesis in axons. Current knowledge might suggest that local translation of tubulin takes place in axons, but far less is known about the post-translational machinery of tubulin biogenesis involving three chaperone complexes: prefoldin, CCT and TBC. We discuss functional understanding of these chaperones from a range of model organisms including yeast, plants, flies and mice, and explain what is known from human diseases. Microtubules across species depend on these chaperones, and they are clearly required in the nervous system. However, most chaperones display a high degree of functional pleiotropy, partly through independent functions of individual subunits outside their complexes, thus posing a challenge to experimental studies. Notably, we found hardly any studies that investigate their presence and function particularly in axons, thus highlighting an important gap in our understanding of axon biology and pathology.
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Affiliation(s)
- Liliana Maria Pinho-Correia
- The University of Manchester, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biology, Manchester, UK
| | - Andreas Prokop
- The University of Manchester, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biology, Manchester, UK.
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8
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Xu L, Chen Z, Li X, Xu H, Zhang Y, Yang W, Chen J, Zhang S, Xu L, Zhou S, Li G, Yu B, Gu X, Yang J. Integrated analyses reveal evolutionarily conserved and specific injury response genes in dorsal root ganglion. Sci Data 2022; 9:666. [PMID: 36323676 PMCID: PMC9630366 DOI: 10.1038/s41597-022-01783-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 10/17/2022] [Indexed: 01/24/2023] Open
Abstract
Rodent dorsal root ganglion (DRG) is widely used for studying axonal injury. Extensive studies have explored genome-wide profiles on rodent DRGs under peripheral nerve insults. However, systematic integration and exploration of these data still be limited. Herein, we re-analyzed 21 RNA-seq datasets and presented a web-based resource (DRGProfile). We identified 53 evolutionarily conserved injury response genes, including well-known injury genes (Atf3, Npy and Gal) and less-studied transcriptional factors (Arid5a, Csrnp1, Zfp367). Notably, we identified species-preference injury response candidates (e.g. Gpr151, Lipn, Anxa10 in mice; Crisp3, Csrp3, Vip, Hamp in rats). Temporal profile analysis reveals expression patterns of genes related to pre-regenerative and regenerating states. Finally, we found a large sex difference in response to sciatic nerve injury, and identified four male-specific markers (Uty, Eif2s3y, Kdm5d, Ddx3y) expressed in DRG. Our study provides a comprehensive integrated landscape for expression change in DRG upon injury which will greatly contribute to the neuroscience community.
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Affiliation(s)
- Lian Xu
- Key Laboratory of Neuroregeneration, Ministry of Education and Jiangsu Province, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, 19# Qixiu Road, Nantong, Jiangsu, 226001, China
| | - Zhifeng Chen
- Key Laboratory of Neuroregeneration, Ministry of Education and Jiangsu Province, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, 19# Qixiu Road, Nantong, Jiangsu, 226001, China
| | - Xiaodi Li
- Nanjing University of Chinese Medicine, Nanjing, China
| | - Hui Xu
- Nantong Institute of Genetics and Reproductive Medicine, Affiliated Maternity and Child Healthcare Hospital of Nantong University, Nantong, Jiangsu, China
| | - Yu Zhang
- Nanjing University of Chinese Medicine, Nanjing, China
| | - Weiwei Yang
- Nanjing University of Chinese Medicine, Nanjing, China
| | - Jing Chen
- Key Laboratory of Neuroregeneration, Ministry of Education and Jiangsu Province, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, 19# Qixiu Road, Nantong, Jiangsu, 226001, China
| | - Shuqiang Zhang
- Key Laboratory of Neuroregeneration, Ministry of Education and Jiangsu Province, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, 19# Qixiu Road, Nantong, Jiangsu, 226001, China
| | - Lingchi Xu
- Key Laboratory of Neuroregeneration, Ministry of Education and Jiangsu Province, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, 19# Qixiu Road, Nantong, Jiangsu, 226001, China
| | - Songlin Zhou
- Key Laboratory of Neuroregeneration, Ministry of Education and Jiangsu Province, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, 19# Qixiu Road, Nantong, Jiangsu, 226001, China
| | - Guicai Li
- Key Laboratory of Neuroregeneration, Ministry of Education and Jiangsu Province, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, 19# Qixiu Road, Nantong, Jiangsu, 226001, China
| | - Bin Yu
- Key Laboratory of Neuroregeneration, Ministry of Education and Jiangsu Province, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, 19# Qixiu Road, Nantong, Jiangsu, 226001, China
| | - Xiaosong Gu
- Key Laboratory of Neuroregeneration, Ministry of Education and Jiangsu Province, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, 19# Qixiu Road, Nantong, Jiangsu, 226001, China.
- Nanjing University of Chinese Medicine, Nanjing, China.
| | - Jian Yang
- Key Laboratory of Neuroregeneration, Ministry of Education and Jiangsu Province, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, 19# Qixiu Road, Nantong, Jiangsu, 226001, China.
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9
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Teliska LH, Dalla Costa I, Sert O, Twiss JL, Rasband MN. Axon Initial Segments Are Required for Efficient Motor Neuron Axon Regeneration and Functional Recovery of Synapses. J Neurosci 2022; 42:8054-8065. [PMID: 36096668 PMCID: PMC9636994 DOI: 10.1523/jneurosci.1261-22.2022] [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: 06/27/2022] [Accepted: 08/02/2022] [Indexed: 11/21/2022] Open
Abstract
The axon initial segment (AIS) generates action potentials and maintains neuronal polarity by regulating the differential trafficking and distribution of proteins, transport vesicles, and organelles. Injury and disease can disrupt the AIS, and the subsequent loss of clustered ion channels and polarity mechanisms may alter neuronal excitability and function. However, the impact of AIS disruption on axon regeneration after injury is unknown. We generated male and female mice with AIS-deficient multipolar motor neurons by deleting AnkyrinG, the master scaffolding protein required for AIS assembly and maintenance. We found that after nerve crush, neuromuscular junction reinnervation was significantly delayed in AIS-deficient motor neurons compared with control mice. In contrast, loss of AnkyrinG from pseudo-unipolar sensory neurons did not impair axon regeneration into the intraepidermal nerve fiber layer. Even after AIS-deficient motor neurons reinnervated the neuromuscular junction, they failed to functionally recover because of reduced synaptic vesicle protein 2 at presynaptic terminals. In addition, mRNA trafficking was disrupted in AIS-deficient axons. Our results show that, after nerve injury, an intact AIS is essential for efficient regeneration and functional recovery of axons in multipolar motor neurons. Our results also suggest that loss of polarity in AIS-deficient motor neurons impairs the delivery of axonal proteins, mRNAs, and other cargoes necessary for regeneration. Thus, therapeutic strategies for axon regeneration must consider preservation or reassembly of the AIS.SIGNIFICANCE STATEMENT Disruption of the axon initial segment is a common event after nervous system injury. For multipolar motor neurons, we show that axon initial segments are essential for axon regeneration and functional recovery after injury. Our results may help explain injuries where axon regeneration fails, and suggest strategies to promote more efficient axon regeneration.
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Affiliation(s)
- Lindsay H Teliska
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Irene Dalla Costa
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina 29208
| | - Ozlem Sert
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina 29208
| | - Matthew N Rasband
- Department of Neuroscience, Baylor College of Medicine, Houston, Texas 77030
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10
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Triantopoulou N, Vidaki M. Local mRNA translation and cytoskeletal reorganization: Mechanisms that tune neuronal responses. Front Mol Neurosci 2022; 15:949096. [PMID: 35979146 PMCID: PMC9376447 DOI: 10.3389/fnmol.2022.949096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 07/07/2022] [Indexed: 12/31/2022] Open
Abstract
Neurons are highly polarized cells with significantly long axonal and dendritic extensions that can reach distances up to hundreds of centimeters away from the cell bodies in higher vertebrates. Their successful formation, maintenance, and proper function highly depend on the coordination of intricate molecular networks that allow axons and dendrites to quickly process information, and respond to a continuous and diverse cascade of environmental stimuli, often without enough time for communication with the soma. Two seemingly unrelated processes, essential for these rapid responses, and thus neuronal homeostasis and plasticity, are local mRNA translation and cytoskeletal reorganization. The axonal cytoskeleton is characterized by high stability and great plasticity; two contradictory attributes that emerge from the powerful cytoskeletal rearrangement dynamics. Cytoskeletal reorganization is crucial during nervous system development and in adulthood, ensuring the establishment of proper neuronal shape and polarity, as well as regulating intracellular transport and synaptic functions. Local mRNA translation is another mechanism with a well-established role in the developing and adult nervous system. It is pivotal for axonal guidance and arborization, synaptic formation, and function and seems to be a key player in processes activated after neuronal damage. Perturbations in the regulatory pathways of local translation and cytoskeletal reorganization contribute to various pathologies with diverse clinical manifestations, ranging from intellectual disabilities (ID) to autism spectrum disorders (ASD) and schizophrenia (SCZ). Despite the fact that both processes are essential for the orchestration of pathways critical for proper axonal and dendritic function, the interplay between them remains elusive. Here we review our current knowledge on the molecular mechanisms and specific interaction networks that regulate and potentially coordinate these interconnected processes.
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Affiliation(s)
- Nikoletta Triantopoulou
- Division of Basic Sciences, Medical School, University of Crete, Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion, Greece
| | - Marina Vidaki
- Division of Basic Sciences, Medical School, University of Crete, Heraklion, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology Hellas (IMBB-FORTH), Heraklion, Greece
- *Correspondence: Marina Vidaki,
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11
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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: 7] [Impact Index Per Article: 3.5] [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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12
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Carey JL, Guo L. Liquid-Liquid Phase Separation of TDP-43 and FUS in Physiology and Pathology of Neurodegenerative Diseases. Front Mol Biosci 2022; 9:826719. [PMID: 35187086 PMCID: PMC8847598 DOI: 10.3389/fmolb.2022.826719] [Citation(s) in RCA: 62] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/11/2022] [Indexed: 12/12/2022] Open
Abstract
Liquid-liquid phase separation of RNA-binding proteins mediates the formation of numerous membraneless organelles with essential cellular function. However, aberrant phase transition of these proteins leads to the formation of insoluble protein aggregates, which are pathological hallmarks of neurodegenerative diseases including ALS and FTD. TDP-43 and FUS are two such RNA-binding proteins that mislocalize and aggregate in patients of ALS and FTD. They have similar domain structures that provide multivalent interactions driving their phase separation in vitro and in the cellular environment. In this article, we review the factors that mediate and regulate phase separation of TDP-43 and FUS. We also review evidences that connect the phase separation property of TDP-43 and FUS to their functional roles in cells. Aberrant phase transition of TDP-43 and FUS leads to protein aggregation and disrupts their regular cell function. Therefore, restoration of functional protein phase of TDP-43 and FUS could be beneficial for neuronal cells. We discuss possible mechanisms for TDP-43 and FUS aberrant phase transition and aggregation while reviewing the methods that are currently being explored as potential therapeutic strategies to mitigate aberrant phase transition and aggregation of TDP-43 and FUS.
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13
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Schaeffer J, Belin S. Axonal protein synthesis in central nervous system regeneration: is building an axon a local matter? Neural Regen Res 2021; 17:987-988. [PMID: 34558513 PMCID: PMC8552839 DOI: 10.4103/1673-5374.324835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Julia Schaeffer
- Université Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble, France
| | - Stephane Belin
- Université Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble, France
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14
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Lee SJ, Zdradzinski MD, Sahoo PK, Kar AN, Patel P, Kawaguchi R, Aguilar BJ, Lantz KD, McCain CR, Coppola G, Lu Q, Twiss JL. Selective axonal translation of the mRNA isoform encoding prenylated Cdc42 supports axon growth. J Cell Sci 2021; 134:237797. [PMID: 33674450 DOI: 10.1242/jcs.251967] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 02/24/2021] [Indexed: 12/13/2022] Open
Abstract
The small Rho-family GTPase Cdc42 has long been known to have a role in cell motility and axon growth. The eukaryotic Ccd42 gene is alternatively spliced to generate mRNAs with two different 3' untranslated regions (UTRs) that encode proteins with distinct C-termini. The C-termini of these Cdc42 proteins include CaaX and CCaX motifs for post-translational prenylation and palmitoylation, respectively. Palmitoyl-Cdc42 protein was previously shown to contribute to dendrite maturation, while the prenyl-Cdc42 protein contributes to axon specification and its mRNA was detected in neurites. Here, we show that the mRNA encoding prenyl-Cdc42 isoform preferentially localizes into PNS axons and this localization selectively increases in vivo during peripheral nervous system (PNS) axon regeneration. Functional studies indicate that prenyl-Cdc42 increases axon length in a manner that requires axonal targeting of its mRNA, which, in turn, needs an intact C-terminal CaaX motif that can drive prenylation of the encoded protein. In contrast, palmitoyl-Cdc42 has no effect on axon growth but selectively increases dendrite length. Together, these data show that alternative splicing of the Cdc42 gene product generates an axon growth promoting, locally synthesized prenyl-Cdc42 protein. This article has an associated First Person interview with one of the co-first authors of the paper.
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Affiliation(s)
- Seung Joon Lee
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Matthew D Zdradzinski
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Priyanka Patel
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Riki Kawaguchi
- Department of Psychiatry, Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA 90095-1761, USA
| | - Byron J Aguilar
- Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Kelsey D Lantz
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Caylee R McCain
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
| | - Giovanni Coppola
- Department of Psychiatry, Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA 90095-1761, USA.,Department of Neurology, Semel Institute for Neuroscience and Human Behavior, Los Angeles, CA 90095-1761, USA
| | - Qun Lu
- Department of Anatomy and Cell Biology, Brody School of Medicine, East Carolina University, Greenville, NC 27834, USA
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208USA
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15
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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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16
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Zhang S, Chen Y, Wang Y, Zhang P, Chen G, Zhou Y. Insights Into Translatomics in the Nervous System. Front Genet 2021; 11:599548. [PMID: 33408739 PMCID: PMC7779767 DOI: 10.3389/fgene.2020.599548] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 11/30/2020] [Indexed: 12/11/2022] Open
Abstract
Most neurological disorders are caused by abnormal gene translation. Generally, dysregulation of elements involved in the translational process disrupts homeostasis in neurons and neuroglia. Better understanding of how the gene translation process occurs requires detailed analysis of transcriptomic and proteomic profile data. However, a lack of strictly direct correlations between mRNA and protein levels limits translational investigation by combining transcriptomic and proteomic profiling. The much better correlation between proteins and translated mRNAs than total mRNAs in abundance and insufficiently sensitive proteomics approach promote the requirement of advances in translatomics technology. Translatomics which capture and sequence the mRNAs associated with ribosomes has been effective in identifying translational changes by genetics or projections, ribosome stalling, local translation, and transcript isoforms in the nervous system. Here, we place emphasis on the main three translatomics methods currently used to profile mRNAs attached to ribosome-nascent chain complex (RNC-mRNA). Their prominent applications in neurological diseases including glioma, neuropathic pain, depression, fragile X syndrome (FXS), neurodegenerative disorders are outlined. The content reviewed here expands our understanding on the contributions of aberrant translation to neurological disease development.
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Affiliation(s)
- Shuxia Zhang
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yeru Chen
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yongjie Wang
- Key Laboratory of Elemene Anti-Cancer Medicine of Zhejiang Province and Holistic Integrative Pharmacy Institutes, Hangzhou Normal University, Hangzhou, China.,Engineering Laboratory of Development and Application of Traditional Chinese Medicine from Zhejiang Province, Holistic Integrative Pharmacy Institutes, Hangzhou Normal University, Hangzhou, China
| | - Piao Zhang
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Gang Chen
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Youfa Zhou
- Department of Anesthesiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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17
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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: 24] [Impact Index Per Article: 6.0] [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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18
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Yin Y, De Lima S, Gilbert HY, Hanovice NJ, Peterson SL, Sand RM, Sergeeva EG, Wong KA, Xie L, Benowitz LI. Optic nerve regeneration: A long view. Restor Neurol Neurosci 2020; 37:525-544. [PMID: 31609715 DOI: 10.3233/rnn-190960] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The optic nerve conveys information about the outside world from the retina to multiple subcortical relay centers. Until recently, the optic nerve was widely believed to be incapable of re-growing if injured, with dire consequences for victims of traumatic, ischemic, or neurodegenerative diseases of this pathway. Over the past 10-20 years, research from our lab and others has made considerable progress in defining factors that normally suppress axon regeneration and the ability of retinal ganglion cells, the projection neurons of the retina, to survive after nerve injury. Here we describe research from our lab on the role of inflammation-derived growth factors, suppression of inter-cellular signals among diverse retinal cell types, and combinatorial therapies, along with related studies from other labs, that enable animals with optic nerve injury to regenerate damaged retinal axons back to the brain. These studies raise the possibility that vision might one day be restored to people with optic nerve damage.
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Affiliation(s)
- Yuqin Yin
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Silmara De Lima
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Hui-Ya Gilbert
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA
| | - Nicholas J Hanovice
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Sheri L Peterson
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Rheanna M Sand
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Elena G Sergeeva
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Boston Children's Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Kimberly A Wong
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Lili Xie
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA
| | - Larry I Benowitz
- Laboratories for Neuroscience Research in Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Boston Children's Hospital, Boston, MA, USA.,F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA, USA.,Department of Neurosurgery, Harvard Medical School, Boston, MA, USA.,Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
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19
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Ostroff LE, Santini E, Sears R, Deane Z, Kanadia RN, LeDoux JE, Lhakhang T, Tsirigos A, Heguy A, Klann E. Axon TRAP reveals learning-associated alterations in cortical axonal mRNAs in the lateral amgydala. eLife 2019; 8:e51607. [PMID: 31825308 PMCID: PMC6924958 DOI: 10.7554/elife.51607] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 12/10/2019] [Indexed: 12/11/2022] Open
Abstract
Local translation can support memory consolidation by supplying new proteins to synapses undergoing plasticity. Translation in adult forebrain dendrites is an established mechanism of synaptic plasticity and is regulated by learning, yet there is no evidence for learning-regulated protein synthesis in adult forebrain axons, which have traditionally been believed to be incapable of translation. Here, we show that axons in the adult rat amygdala contain translation machinery, and use translating ribosome affinity purification (TRAP) with RNASeq to identify mRNAs in cortical axons projecting to the amygdala, over 1200 of which were regulated during consolidation of associative memory. Mitochondrial and translation-related genes were upregulated, whereas synaptic, cytoskeletal, and myelin-related genes were downregulated; the opposite effects were observed in the cortex. Our results demonstrate that axonal translation occurs in the adult forebrain and is altered after learning, supporting the likelihood that local translation is more a rule than an exception in neuronal processes.
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Affiliation(s)
- Linnaea E Ostroff
- Department of Physiology and NeurobiologyUniversity of ConnecticutStorrsUnited States
| | | | - Robert Sears
- Center for Neural ScienceNew York UniversityNew YorkUnited States
- Emotional Brain InstituteNathan Kline Institute for Psychiatry ResearchOrangeburgUnited States
- Department of Child and Adolescent PsychiatryNew York University School of MedicineNew YorkUnited States
| | - Zachary Deane
- Department of Physiology and NeurobiologyUniversity of ConnecticutStorrsUnited States
| | - Rahul N Kanadia
- Department of Physiology and NeurobiologyUniversity of ConnecticutStorrsUnited States
| | - Joseph E LeDoux
- Center for Neural ScienceNew York UniversityNew YorkUnited States
- Emotional Brain InstituteNathan Kline Institute for Psychiatry ResearchOrangeburgUnited States
| | - Tenzin Lhakhang
- Applied Bioinformatics LaboratoriesNew York University School of MedicineNew YorkUnited States
| | - Aristotelis Tsirigos
- Applied Bioinformatics LaboratoriesNew York University School of MedicineNew YorkUnited States
- Department of PathologyNew York University School of MedicineNew YorkUnited States
| | - Adriana Heguy
- Department of PathologyNew York University School of MedicineNew YorkUnited States
- Genome Technology CenterNew York University School of MedicineNew YorkUnited States
| | - Eric Klann
- Center for Neural ScienceNew York UniversityNew YorkUnited States
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20
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Fawcett JW. The Struggle to Make CNS Axons Regenerate: Why Has It Been so Difficult? Neurochem Res 2019; 45:144-158. [PMID: 31388931 PMCID: PMC6942574 DOI: 10.1007/s11064-019-02844-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 07/09/2019] [Accepted: 07/19/2019] [Indexed: 12/12/2022]
Abstract
Axon regeneration in the CNS is inhibited by many extrinsic and intrinsic factors. Because these act in parallel, no single intervention has been sufficient to enable full regeneration of damaged axons in the adult mammalian CNS. In the external environment, NogoA and CSPGs are strongly inhibitory to the regeneration of adult axons. CNS neurons lose intrinsic regenerative ability as they mature: embryonic but not mature neurons can grow axons for long distances when transplanted into the adult CNS, and regeneration fails with maturity in in vitro axotomy models. The causes of this loss of regeneration include partitioning of neurons into axonal and dendritic fields with many growth-related molecules directed specifically to dendrites and excluded from axons, changes in axonal signalling due to changes in expression and localization of receptors and their ligands, changes in local translation of proteins in axons, and changes in cytoskeletal dynamics after injury. Also with neuronal maturation come epigenetic changes in neurons, with many of the transcription factor binding sites that drive axon growth-related genes becoming inaccessible. The overall aim for successful regeneration is to ensure that the right molecules are expressed after axotomy and to arrange for them to be transported to the right place in the neuron, including the damaged axon tip.
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Affiliation(s)
- James W Fawcett
- John Van Geest Centre for Brain Repair, University of Cambridge, Robinson Way, Cambridge, CB2 0PY, UK.
- Centre of Reconstructive Neuroscience, Institute for Experimental Medicine ASCR, Prague, Czech Republic.
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21
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Farley MM, Watkins TA. Intrinsic Neuronal Stress Response Pathways in Injury and Disease. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2019; 13:93-116. [PMID: 29414247 DOI: 10.1146/annurev-pathol-012414-040354] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
From injury to disease to aging, neurons, like all cells, may face various insults that can impact their function and survival. Although the consequences are substantially dictated by the type, context, and severity of insult, distressed neurons are far from passive. Activation of cellular stress responses aids in the preservation or restoration of nervous system function. However, stress responses themselves can further advance neuropathology and contribute significantly to neuronal dysfunction and neurodegeneration. Here we explore the recent advances in defining the cellular stress responses within neurodegenerative diseases and neuronal injury, and we emphasize axonal injury as a well-characterized model of neuronal insult. We highlight key findings and unanswered questions about neuronal stress response pathways, from the initial detection of cellular insults through the underlying mechanisms of the responses to their ultimate impact on the fates of distressed neurons.
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Affiliation(s)
- Madeline M Farley
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030;
| | - Trent A Watkins
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas 77030;
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22
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Ding D, Enriquez-Algeciras M, Valdivia AO, Torres J, Pole C, Thompson JW, Chou TH, Perez-Pinzon M, Porciatti V, Udin S, Nestler E, Bhattacharya SK. The Role of Deimination in Regenerative Reprogramming of Neurons. Mol Neurobiol 2019; 56:2618-2639. [PMID: 30051351 PMCID: PMC6348056 DOI: 10.1007/s12035-018-1262-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/17/2018] [Indexed: 10/28/2022]
Abstract
Neurons from the adult central nervous system (CNS) demonstrate limited mRNA transport and localized protein synthesis versus developing neurons, correlating with lower regenerative capacity. We found that deimination (posttranslational conversion of protein-bound arginine into citrulline) undergoes upregulation during early neuronal development while declining to a low basal level in adults. This modification is associated with neuronal arborization from amphibians to mammals. The mRNA-binding proteins (ANP32a, REF), deiminated in neurons, have been implicated in local protein synthesis. Overexpression of the deiminating cytosolic enzyme peptidyl arginine deiminase 2 in nervous systems results in increased neuronal transport and neurite outgrowth. We further demonstrate that enriching deiminated proteins rescues transport deficiencies both in primary neurons and mouse optic nerve even in the presence of pharmacological transport blockers. We conclude that deimination promotes neuronal outgrowth via enhanced transport and local protein synthesis and represents a new avenue for neuronal regeneration in the adult CNS.
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Affiliation(s)
- Di Ding
- Bascom Palmer Eye Institute, University of Miami, 1638 N.W. 10th Avenue, #706, Miami, FL, 33136, USA
- Department of Ophthalmology/Neuroscience Program, University of Miami, Miami, FL, 33136, USA
| | - Mabel Enriquez-Algeciras
- Bascom Palmer Eye Institute, University of Miami, 1638 N.W. 10th Avenue, #706, Miami, FL, 33136, USA
- Department of Ophthalmology/Neuroscience Program, University of Miami, Miami, FL, 33136, USA
| | - Anddre Osmar Valdivia
- Bascom Palmer Eye Institute, University of Miami, 1638 N.W. 10th Avenue, #706, Miami, FL, 33136, USA
- Department of Ophthalmology/Neuroscience Program, University of Miami, Miami, FL, 33136, USA
| | - Juan Torres
- Bascom Palmer Eye Institute, University of Miami, 1638 N.W. 10th Avenue, #706, Miami, FL, 33136, USA
- Department of Ophthalmology/Neuroscience Program, University of Miami, Miami, FL, 33136, USA
| | - Cameron Pole
- Department of Ophthalmology/Neuroscience Program, University of Miami, Miami, FL, 33136, USA
| | - John W Thompson
- Neurological Surgery, University of Miami, Miami, FL, 33136, USA
| | - Tsung-Han Chou
- Bascom Palmer Eye Institute, University of Miami, 1638 N.W. 10th Avenue, #706, Miami, FL, 33136, USA
- Department of Ophthalmology/Neuroscience Program, University of Miami, Miami, FL, 33136, USA
| | - Miguel Perez-Pinzon
- Department of Ophthalmology/Neuroscience Program, University of Miami, Miami, FL, 33136, USA
- Department of Neurology, University of Miami, Miami, FL, 33136, USA
| | - Vittorio Porciatti
- Bascom Palmer Eye Institute, University of Miami, 1638 N.W. 10th Avenue, #706, Miami, FL, 33136, USA
- Department of Ophthalmology/Neuroscience Program, University of Miami, Miami, FL, 33136, USA
| | - Susan Udin
- Department of Physiology and Biophysics, State University of New York, Buffalo, 553 Biomedical Res. Building, Buffalo, NY, 14214, USA
| | - Eric Nestler
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1065, New York, NY, 10029, USA
| | - Sanjoy K Bhattacharya
- Bascom Palmer Eye Institute, University of Miami, 1638 N.W. 10th Avenue, #706, Miami, FL, 33136, USA.
- Department of Ophthalmology/Neuroscience Program, University of Miami, Miami, FL, 33136, USA.
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23
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Tang BL. Why is NMNAT Protective against Neuronal Cell Death and Axon Degeneration, but Inhibitory of Axon Regeneration? Cells 2019; 8:cells8030267. [PMID: 30901919 PMCID: PMC6468476 DOI: 10.3390/cells8030267] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 03/15/2019] [Accepted: 03/18/2019] [Indexed: 02/06/2023] Open
Abstract
Nicotinamide mononucleotide adenylyltransferase (NMNAT), a key enzyme for NAD+ synthesis, is well known for its activity in neuronal survival and attenuation of Wallerian degeneration. Recent investigations in invertebrate models have, however, revealed that NMNAT activity negatively impacts upon axon regeneration. Overexpression of Nmnat in laser-severed Drosophila sensory neurons reduced axon regeneration, while axon regeneration was enhanced in injured mechanosensory axons in C. elegansnmat-2 null mutants. These diametrically opposite effects of NMNAT orthologues on neuroprotection and axon regeneration appear counterintuitive as there are many examples of neuroprotective factors that also promote neurite outgrowth, and enhanced neuronal survival would logically facilitate regeneration. We suggest here that while NMNAT activity and NAD+ production activate neuroprotective mechanisms such as SIRT1-mediated deacetylation, the same mechanisms may also activate a key axonal regeneration inhibitor, namely phosphatase and tensin homolog (PTEN). SIRT1 is known to deacetylate and activate PTEN which could, in turn, suppress PI3 kinase–mTORC1-mediated induction of localized axonal protein translation, an important process that determines successful regeneration. Strategic tuning of Nmnat activity and NAD+ production in axotomized neurons may thus be necessary to promote initial survival without inhibiting subsequent regeneration.
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Affiliation(s)
- Bor Luen Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore.
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore 117597, Singapore.
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24
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Koley S, Rozenbaum M, Fainzilber M, Terenzio M. Translating regeneration: Local protein synthesis in the neuronal injury response. Neurosci Res 2019; 139:26-36. [DOI: 10.1016/j.neures.2018.10.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 09/13/2018] [Accepted: 10/02/2018] [Indexed: 12/21/2022]
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25
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Shrestha S, Phay M, Kim HH, Pouladvand P, Lee SJ, Yoo S. Differential regulation of brain-derived neurotrophic factor (BDNF) expression in sensory neuron axons by miRNA-206. FEBS Open Bio 2019; 9:374-383. [PMID: 30761261 PMCID: PMC6356166 DOI: 10.1002/2211-5463.12581] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 01/27/2023] Open
Abstract
Distinct subcellular localization and subsequent translational control of 3′ UTR variants of mRNA encoding brain‐derived neurotrophic factor (BDNF) are critical for the development and plasticity of neurons. Although the processes that lead to preferential localization of BDNF have been well studied, it is still not clear how neurons ensure differential BDNF production in a spatial‐specific manner. Here, we identified that microRNA (miRNA)‐206 has the potential to specifically regulate BDNF with a long 3′ UTR without affecting its short 3′ UTR counterpart. Overexpression of miRNA‐206 in sensory neurons resulted in a 30% and 45% reduction of BDNF protein expression in the cell bodies and axons, respectively. The work described in the present study indicates that miRNAs can differentially and specifically regulate the expression of transcript variants with different localization patterns.
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Affiliation(s)
- Shiva Shrestha
- Nemours Biomedical Research Alfred I. duPont Hospital for Children Wilmington DE USA.,Department of Biological Sciences University of Delaware Newark DE USA.,Gene Therapy Program Perelman School of Medicine University of Pennsylvania Philadelphia PA USA
| | - Monichan Phay
- Nemours Biomedical Research Alfred I. duPont Hospital for Children Wilmington DE USA.,Department of Biological Sciences University of Delaware Newark DE USA
| | - Hak Hee Kim
- Nemours Biomedical Research Alfred I. duPont Hospital for Children Wilmington DE USA
| | - Pedram Pouladvand
- Department of Biological Sciences University of Delaware Newark DE USA.,Department of Biology Pennsylvania State University-Brandywine Media PA USA
| | - Seung Joon Lee
- Department of Biological Sciences University of South Carolina Columbia SC USA
| | - Soonmoon Yoo
- Nemours Biomedical Research Alfred I. duPont Hospital for Children Wilmington DE USA.,Department of Biological Sciences University of Delaware Newark DE USA
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26
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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: 99] [Impact Index Per Article: 16.5] [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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27
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Zhang J, Yang D, Huang H, Sun Y, Hu Y. Coordination of Necessary and Permissive Signals by PTEN Inhibition for CNS Axon Regeneration. Front Neurosci 2018; 12:558. [PMID: 30158848 PMCID: PMC6104488 DOI: 10.3389/fnins.2018.00558] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 07/24/2018] [Indexed: 12/22/2022] Open
Abstract
In the nearly 10 years since PTEN was identified as a prominent intrinsic inhibitor of CNS axon regeneration, the PTEN negatively regulated PI3K-AKT-mTOR pathway has been intensively explored in diverse models of axon injury and diseases and its mechanism for axon regeneration is becoming clearer. It is therefore timely to summarize current knowledge and discuss future directions of translational regenerative research for neural injury and neurodegenerative diseases. Using mouse optic nerve crush as an in vivo retinal ganglion cell axon injury model, we have conducted an extensive molecular dissection of the PI3K-AKT pathway to illuminate the cross-regulating mechanisms in axon regeneration. AKT is the nodal point that coordinates both positive and negative signals to regulate adult CNS axon regeneration through two parallel pathways, activating mTORC1 and inhibiting GSK3ββ. Activation of mTORC1 or its effector S6K1 alone can only slightly promote axon regeneration, whereas blocking mTORC1 significantly prevent axon regeneration, suggesting the necessary role of mTORC1 in axon regeneration. However, mTORC1/S6K1-mediated feedback inhibition prevents potent AKT activation, which suggests a key permissive signal from an unidentified AKT-independent pathway is required for stimulating the neuron-intrinsic growth machinery. Future studies into this complex neuron-intrinsic balancing mechanism involving necessary and permissive signals for axon regeneration is likely to lead eventually to safe and effective regenerative strategies for CNS repair.
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Affiliation(s)
- Jie Zhang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States.,Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dakai Yang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Haoliang Huang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA, United States
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28
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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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29
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González C, Cornejo VH, Couve A. Golgi bypass for local delivery of axonal proteins, fact or fiction? Curr Opin Cell Biol 2018; 53:9-14. [PMID: 29631154 DOI: 10.1016/j.ceb.2018.03.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/26/2018] [Accepted: 03/29/2018] [Indexed: 02/07/2023]
Abstract
Although translation of cytosolic proteins is well described in axons, much less is known about the synthesis, processing and trafficking of transmembrane and secreted proteins. A canonical rough endoplasmic reticulum or a stacked Golgi apparatus has not been detected in axons, generating doubts about the functionality of a local route. However, axons contain mRNAs for membrane and secreted proteins, translation factors, ribosomal components, smooth endoplasmic reticulum and post-endoplasmic reticulum elements that may contribute to local biosynthesis and plasma membrane delivery. Here we consider the evidence supporting a local secretory system in axons. We discuss exocytic elements and examples of autonomous axonal trafficking that impact development and maintenance. We also examine whether unconventional post-endoplasmic reticulum pathways may replace the canonical Golgi apparatus.
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Affiliation(s)
- Carolina González
- Department of Neuroscience, Facultad de Medicina, Universidad de Chile, Chile; Biomedical Neuroscience Institute (BNI), Facultad de Medicina, Universidad de Chile, Chile
| | - Víctor Hugo Cornejo
- Department of Neuroscience, Facultad de Medicina, Universidad de Chile, Chile; Biomedical Neuroscience Institute (BNI), Facultad de Medicina, Universidad de Chile, Chile
| | - Andrés Couve
- Department of Neuroscience, Facultad de Medicina, Universidad de Chile, Chile; Biomedical Neuroscience Institute (BNI), Facultad de Medicina, Universidad de Chile, Chile.
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30
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Dong H, Luo X, Niu Y, Yu N, Gao R, Wang H, Yang L, Huang J. Neuritin 1 expression in human normal tissues and its association with various human cancers. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2018; 11:1956-1964. [PMID: 31938301 PMCID: PMC6958223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 03/28/2018] [Indexed: 06/10/2023]
Abstract
OBJECTIVE(S) Neuritin (Nrn1) is a glycophosphatidylinositol-linked protein that can be induced by neural activity in the central nervous system. However, its expression outside the nervous system and association with human cancers is unclear. This study investigated the expression of Nrn1 in human tissues as well as its association with human cancers. MATERIALS AND METHODS Nrn1 gene expression in human adult tissues was evaluated with the Clontech Multiple Tissue cDNA panel. Nrn1 protein in various tissues was detected by immunohistochemistry. Signal v.4.0 and TMHMM v.2.0 software were used to identify the signal peptide and transmembrane helix of Nrn1. The subcellular localization of Nrn1 in cultured SH-SY5Y cells was assessed by immunocytochemistry and western blotting. The expression of Nrn1 in human cancers were assessed using the online tools GEPIA. RESULTS Nrn1 mRNA was expressed in various tissues, compared to mRNA levels in the brain tissues, expression was high in the placenta, lungs, skeletal muscle, thymus, pancreas, liver and the heart tissues; lower levels were detected in the small intestine, ovary, spleen, and testes, but there was no detectable expression in the kidneys, colon, prostate or leukocytes. In SY5Y cells, Nrn1 was colocalized with caveolin 1 at the plasma membrane. Nrn1 was downregulated in Bladder Urothelial Carcinoma (BLCA); Breast invasive carcinoma (BRCA); Cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC); Colon adenocarcinoma (COAD); Glioblastoma multiforme (GBM); Kidney Chromophobe (KIHC); Kidney renal papillary cell carcinoma (KIRP); Lower Grade GLioma (LGG); Rectum adenocarcinoma (READ); Uterine Corpus Endometrial Carcinoma (UCEC); Lung adenocarcinoma (LUA), Ovarian serous cystadenocarcinoma (OV) and upregulated in Lymphoid Neoplasm Diffuse Large B-cell Lymphoma (DLBC). A combination of the overall survival analysis of the 12 kinds of human tumors with Nrn1 downregulation revealed that patients with high levels of Nrn1 present a long term survival. But there is no significant effect on DLBC patients' survival. CONCLUSION Nrn1 is expressed in various human tissues including the nervous system, specifically in the lipid rafts of cell membranes. We also provided the strong evidence that Nrn1 is associated with 13 kinds of human cancers and could function as biomarkers and therapeutic targets for these cancers.
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Affiliation(s)
- Hongchang Dong
- Department of Biochemistry, The Key Laboratory of Xinjiang Endemic & Ethnic Diseases, School of Medicine, Shihezi UniversityShihezi 832002, Xinjiang, China
| | - Xing Luo
- Department of Biochemistry, The Key Laboratory of Xinjiang Endemic & Ethnic Diseases, School of Medicine, Shihezi UniversityShihezi 832002, Xinjiang, China
| | - Yuqin Niu
- Medical Center of The Affiliated Hospital of Shihezi UniversityShihezi, Xinjiang, China
| | - Na Yu
- Department of Biochemistry, The Key Laboratory of Xinjiang Endemic & Ethnic Diseases, School of Medicine, Shihezi UniversityShihezi 832002, Xinjiang, China
| | - Rui Gao
- Department of Biochemistry, The Key Laboratory of Xinjiang Endemic & Ethnic Diseases, School of Medicine, Shihezi UniversityShihezi 832002, Xinjiang, China
| | - Haiyan Wang
- Department of Biochemistry, The Key Laboratory of Xinjiang Endemic & Ethnic Diseases, School of Medicine, Shihezi UniversityShihezi 832002, Xinjiang, China
- Hangzhou Normal UniversityHangzhou, Zhejiang, China
| | - Li Yang
- Department of Biochemistry, The Key Laboratory of Xinjiang Endemic & Ethnic Diseases, School of Medicine, Shihezi UniversityShihezi 832002, Xinjiang, China
| | - Jin Huang
- Department of Biochemistry, The Key Laboratory of Xinjiang Endemic & Ethnic Diseases, School of Medicine, Shihezi UniversityShihezi 832002, Xinjiang, China
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31
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Müller K, Schnatz A, Schillner M, Woertge S, Müller C, von Graevenitz I, Waisman A, van Minnen J, Vogelaar CF. A predominantly glial origin of axonal ribosomes after nerve injury. Glia 2018; 66:1591-1610. [DOI: 10.1002/glia.23327] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 02/26/2018] [Accepted: 02/27/2018] [Indexed: 01/24/2023]
Affiliation(s)
- Kerstin Müller
- Institute for Microanatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
| | - Andrea Schnatz
- Institute for Microanatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
- Institute of Developmental Biology and Neurobiology, Section Cellular Neurobiology, Johannes Gutenberg University Mainz; Mainz 55099 Germany
| | - Miriam Schillner
- Department of Neurology, Section Neuroimmunology; University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
| | - Simone Woertge
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
| | - Christina Müller
- Institute of Developmental Biology and Neurobiology, Section Cellular Neurobiology, Johannes Gutenberg University Mainz; Mainz 55099 Germany
| | - Ilse von Graevenitz
- Institute for Microanatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
| | - Ari Waisman
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
| | - Jan van Minnen
- Hotchkiss Brain Institute and Cumming School of Medicine; University of Calgary, 3330 Hospital Drive NW; Calgary Alberta T2N 4N1 Canada
| | - Christina F. Vogelaar
- Institute for Microanatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
- Department of Neurology, Section Neuroimmunology; University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
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32
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Terenzio M, Koley S, Samra N, Rishal I, Zhao Q, Sahoo PK, Urisman A, Marvaldi L, Oses-Prieto JA, Forester C, Gomes C, Kalinski AL, Di Pizio A, Doron-Mandel E, Perry RBT, Koppel I, Twiss JL, Burlingame AL, Fainzilber M. Locally translated mTOR controls axonal local translation in nerve injury. Science 2018; 359:1416-1421. [PMID: 29567716 PMCID: PMC6501578 DOI: 10.1126/science.aan1053] [Citation(s) in RCA: 174] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Revised: 12/13/2017] [Accepted: 01/30/2018] [Indexed: 12/12/2022]
Abstract
How is protein synthesis initiated locally in neurons? We found that mTOR (mechanistic target of rapamycin) was activated and then up-regulated in injured axons, owing to local translation of mTOR messenger RNA (mRNA). This mRNA was transported into axons by the cell size-regulating RNA-binding protein nucleolin. Furthermore, mTOR controlled local translation in injured axons. This included regulation of its own translation and that of retrograde injury signaling molecules such as importin β1 and STAT3 (signal transducer and activator of transcription 3). Deletion of the mTOR 3' untranslated region (3'UTR) in mice reduced mTOR in axons and decreased local translation after nerve injury. Both pharmacological inhibition of mTOR in axons and deletion of the mTOR 3'UTR decreased proprioceptive neuronal survival after nerve injury. Thus, mRNA localization enables spatiotemporal control of mTOR pathways regulating local translation and long-range intracellular signaling.
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Affiliation(s)
- Marco Terenzio
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Sandip Koley
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Nitzan Samra
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ida Rishal
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Qian Zhao
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Anatoly Urisman
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Letizia Marvaldi
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Juan A Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Craig Forester
- Division of Pediatric Allergy, Immunology and Bone Marrow Transplantation, University of California, San Francisco, CA 94158, USA
| | - Cynthia Gomes
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Ashley L Kalinski
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Agostina Di Pizio
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ella Doron-Mandel
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Rotem Ben-Tov Perry
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Indrek Koppel
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Mike Fainzilber
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
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33
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Lou WPK, Mateos A, Koch M, Klussman S, Yang C, Lu N, Kumar S, Limpert S, Göpferich M, Zschaetzsch M, Sliwinski C, Kenzelmann M, Seedorf M, Maillo C, Senis E, Grimm D, Puttagunta R, Mendez R, Liu K, Hassan BA, Martin-Villalba A. Regulation of Adult CNS Axonal Regeneration by the Post-transcriptional Regulator Cpeb1. Front Mol Neurosci 2018; 10:445. [PMID: 29379413 PMCID: PMC5770975 DOI: 10.3389/fnmol.2017.00445] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/20/2017] [Indexed: 12/19/2022] Open
Abstract
Adult mammalian central nervous system (CNS) neurons are unable to regenerate following axonal injury, leading to permanent functional impairments. Yet, the reasons underlying this regeneration failure are not fully understood. Here, we studied the transcriptome and translatome shortly after spinal cord injury. Profiling of the total and ribosome-bound RNA in injured and naïve spinal cords identified a substantial post-transcriptional regulation of gene expression. In particular, transcripts associated with nervous system development were down-regulated in the total RNA fraction while remaining stably loaded onto ribosomes. Interestingly, motif association analysis of post-transcriptionally regulated transcripts identified the cytoplasmic polyadenylation element (CPE) as enriched in a subset of these transcripts that was more resistant to injury-induced reduction at the transcriptome level. Modulation of these transcripts by overexpression of the CPE binding protein, Cpeb1, in mouse and Drosophila CNS neurons promoted axonal regeneration following injury. Our study uncovered a global evolutionarily conserved post-transcriptional mechanism enhancing regeneration of injured CNS axons.
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Affiliation(s)
- Wilson Pak-Kin Lou
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
- Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
| | - Alvaro Mateos
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
| | - Marta Koch
- VIB Center for the Biology of Disease and Center for Human Genetics, VIB and KU Leuven, Leuven, Belgium
| | - Stefan Klussman
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
- Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
| | - Chao Yang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, Hong Kong
| | - Na Lu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, Hong Kong
| | - Sachin Kumar
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
- Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
| | - Stefanie Limpert
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
| | - Manuel Göpferich
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
- Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
| | - Marlen Zschaetzsch
- VIB Center for the Biology of Disease and Center for Human Genetics, VIB and KU Leuven, Leuven, Belgium
| | - Christopher Sliwinski
- Department of Neuroregeneration, University Hospital Heidelberg, Heidelberg, Germany
| | - Marc Kenzelmann
- Division of Molecular Biology of the Cell I, German Cancer Research Center, Heidelberg, Germany
| | - Matthias Seedorf
- Zentrum für Molekulare Biologie, University of Heidelberg, Heidelberg, Germany
| | - Carlos Maillo
- Translational Control of Cell Cycle and Differentiation, Institute for Research in Biomedicine, Barcelona, Spain
| | - Elena Senis
- Virus Host Interaction, Heidelberg University Hospital, Center for Infectious Diseases/Virology, Cluster of Excellence CellNetworks, BioQuant, Heidelberg, Germany
| | - Dirk Grimm
- Virus Host Interaction, Heidelberg University Hospital, Center for Infectious Diseases/Virology, Cluster of Excellence CellNetworks, BioQuant, Heidelberg, Germany
| | - Radhika Puttagunta
- Department of Neuroregeneration, University Hospital Heidelberg, Heidelberg, Germany
| | - Raul Mendez
- Translational Control of Cell Cycle and Differentiation, Institute for Research in Biomedicine, Barcelona, Spain
| | - Kai Liu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, Hong Kong
- Center of Systems Biology and Human Health, School of Science and Institute for Advanced Study, Hong Kong University of Science and Technology, Hong Kong, Hong Kong
| | - Bassem A. Hassan
- VIB Center for the Biology of Disease and Center for Human Genetics, VIB and KU Leuven, Leuven, Belgium
- Sorbonne Universités, UPMC Univ Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et de la Moelle epiniere - Hôpital Pitié-Salpêtrière, Paris, France
| | - Ana Martin-Villalba
- Division of Molecular Neurobiology, German Cancer Research Center, Heidelberg, Germany
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34
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Luarte A, Cornejo VH, Bertin F, Gallardo J, Couve A. The axonal endoplasmic reticulum: One organelle-many functions in development, maintenance, and plasticity. Dev Neurobiol 2017; 78:181-208. [PMID: 29134778 DOI: 10.1002/dneu.22560] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Revised: 11/02/2017] [Accepted: 11/07/2017] [Indexed: 12/11/2022]
Abstract
The endoplasmic reticulum (ER) is highly conserved in eukaryotes and neurons. Indeed, the localization of the organelle in axons has been known for nearly half a century. However, the relevance of the axonal ER is only beginning to emerge. In this review, we discuss the structure of the ER in axons, examining the role of ER-shaping proteins and highlighting reticulons. We analyze the multiple functions of the ER and their potential contribution to axonal physiology. First, we examine the emerging roles of the axonal ER in lipid synthesis, protein translation, processing, quality control, and secretory trafficking of transmembrane proteins. We also review the impact of the ER on calcium dynamics, focusing on intracellular mechanisms and functions. We describe the interactions between the ER and endosomes, mitochondria, and synaptic vesicles. Finally, we analyze available proteomic data of axonal preparations to reveal the dynamic functionality of the ER in axons during development. We suggest that the dynamic proteome and a validated axonal interactome, together with state-of-the-art methodologies, may provide interesting research avenues in axon physiology that may extend to pathology and regeneration. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 181-208, 2018.
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Affiliation(s)
- Alejandro Luarte
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Víctor Hugo Cornejo
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Francisca Bertin
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Javiera Gallardo
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Andrés Couve
- Department of Neuroscience, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, Universidad de Chile, Santiago, Chile
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35
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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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36
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Akins MR, Berk-Rauch HE, Kwan KY, Mitchell ME, Shepard KA, Korsak LIT, Stackpole EE, Warner-Schmidt JL, Sestan N, Cameron HA, Fallon JR. Axonal ribosomes and mRNAs associate with fragile X granules in adult rodent and human brains. Hum Mol Genet 2017; 26:192-209. [PMID: 28082376 DOI: 10.1093/hmg/ddw381] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 11/03/2016] [Indexed: 11/14/2022] Open
Abstract
Local mRNA translation in growing axons allows for rapid and precise regulation of protein expression in response to extrinsic stimuli. However, the role of local translation in mature CNS axons is unknown. Such a mechanism requires the presence of translational machinery and associated mRNAs in circuit-integrated brain axons. Here we use a combination of genetic, quantitative imaging and super-resolution microscopy approaches to show that mature axons in the mammalian brain contain ribosomes, the translational regulator FMRP and a subset of FMRP mRNA targets. This axonal translational machinery is associated with Fragile X granules (FXGs), which are restricted to axons in a stereotyped subset of brain circuits. FXGs and associated axonal translational machinery are present in hippocampus in humans as old as 57 years. This FXG-associated axonal translational machinery is present in adult rats, even when adult neurogenesis is blocked. In contrast, in mouse this machinery is only observed in juvenile hippocampal axons. This differential developmental expression was specific to the hippocampus, as both mice and rats exhibit FXGs in mature axons in the adult olfactory system. Experiments in Fmr1 null mice show that FMRP regulates axonal protein expression but is not required for axonal transport of ribosomes or its target mRNAs. Axonal translational machinery is thus a feature of adult CNS neurons. Regulation of this machinery by FMRP could support complex behaviours in humans throughout life.
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Affiliation(s)
- Michael R Akins
- Department of Biology, Drexel University, Philadelphia, PA, USA.,Department of Neuroscience, Brown University, Providence, RI
| | | | - Kenneth Y Kwan
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT, USA
| | | | | | - Lulu I T Korsak
- Department of Biology, Drexel University, Philadelphia, PA, USA
| | | | | | - Nenad Sestan
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT, USA
| | - Heather A Cameron
- Section on Neuroplasticity, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Justin R Fallon
- Department of Neuroscience, Brown University, Providence, RI
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37
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Gomes C, Lee SJ, Gardiner AS, Smith T, Sahoo PK, Patel P, Thames E, Rodriguez R, Taylor R, Yoo S, Heise T, Kar AN, Perrone-Bizzozero N, Twiss JL. Axonal localization of neuritin/CPG15 mRNA is limited by competition for HuD binding. J Cell Sci 2017; 130:3650-3662. [PMID: 28871047 DOI: 10.1242/jcs.201244] [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] [Received: 01/03/2017] [Accepted: 08/31/2017] [Indexed: 01/11/2023] Open
Abstract
HuD protein (also known as ELAVL4) has been shown to stabilize mRNAs with AU-rich elements (ARE) in their 3' untranslated regions (UTRs), including Gap43, which has been linked to axon growth. HuD also binds to neuritin (Nrn1) mRNA, whose 3'UTR contains ARE sequences. Although the Nrn1 3'UTR has been shown to mediate its axonal localization in embryonic hippocampal neurons, it is not active in adult dorsal root ganglion (DRG) neurons. Here, we asked why the 3'UTR is not sufficient to mediate the axonal localization of Nrn1 mRNA in DRG neurons. HuD overexpression increases the ability of the Nrn1 3'UTR to mediate axonal localizing in DRG neurons. HuD binds directly to the Nrn1 ARE with about a two-fold higher affinity than to the Gap43 ARE. Although the Nrn1 ARE can displace the Gap43 ARE from HuD binding, HuD binds to the full 3'UTR of Gap43 with higher affinity, such that higher levels of Nrn1 are needed to displace the Gap43 3'UTR. The Nrn1 3'UTR can mediate a higher level of axonal localization when endogenous Gap43 is depleted from DRG neurons. Taken together, our data indicate that endogenous Nrn1 and Gap43 mRNAs compete for binding to HuD for their axonal localization and activity of the Nrn1 3'UTR.
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Affiliation(s)
- Cynthia Gomes
- 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
| | - Amy S Gardiner
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
| | - Terika Smith
- 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
| | - Priyanka Patel
- 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
| | - Reycel Rodriguez
- Department of Biochemistry, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Ross Taylor
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Soonmoon Yoo
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, DE 19803, USA
| | - Tilman Heise
- Department of Biochemistry, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Amar N Kar
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Nora Perrone-Bizzozero
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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38
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Sleat DE, Tannous A, Sohar I, Wiseman JA, Zheng H, Qian M, Zhao C, Xin W, Barone R, Sims KB, Moore DF, Lobel P. Proteomic Analysis of Brain and Cerebrospinal Fluid from the Three Major Forms of Neuronal Ceroid Lipofuscinosis Reveals Potential Biomarkers. J Proteome Res 2017; 16:3787-3804. [PMID: 28792770 DOI: 10.1021/acs.jproteome.7b00460] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Clinical trials have been conducted for the neuronal ceroid lipofuscinoses (NCLs), a group of neurodegenerative lysosomal diseases that primarily affect children. Whereas clinical rating systems will evaluate long-term efficacy, biomarkers to measure short-term response to treatment would be extremely valuable. To identify candidate biomarkers, we analyzed autopsy brain and matching CSF samples from controls and three genetically distinct NCLs due to deficiencies in palmitoyl protein thioesterase 1 (CLN1 disease), tripeptidyl peptidase 1 (CLN2 disease), and CLN3 protein (CLN3 disease). Proteomic and biochemical methods were used to analyze lysosomal proteins, and, in general, we find that changes in protein expression compared with control were most similar between CLN2 disease and CLN3 disease. This is consistent with previous observations of biochemical similarities between these diseases. We also conducted unbiased proteomic analyses of CSF and brain using isobaric labeling/quantitative mass spectrometry. Significant alterations in protein expression were identified in each NCL, including reduced STXBP1 in CLN1 disease brain. Given the confounding variable of post-mortem changes, additional validation is required, but this study provides a useful starting set of candidate NCL biomarkers for further evaluation.
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Affiliation(s)
- David E Sleat
- Center for Advanced Biotechnology and Medicine , Piscataway, New Jersey 08854, United States.,Department of Biochemistry and Molecular Biology, Robert-Wood Johnson Medical School, Rutgers Biomedical Health Sciences , Piscataway, New Jersey 08854, United States
| | - Abla Tannous
- Center for Advanced Biotechnology and Medicine , Piscataway, New Jersey 08854, United States
| | - Istvan Sohar
- Center for Advanced Biotechnology and Medicine , Piscataway, New Jersey 08854, United States
| | - Jennifer A Wiseman
- Center for Advanced Biotechnology and Medicine , Piscataway, New Jersey 08854, United States
| | - Haiyan Zheng
- Center for Advanced Biotechnology and Medicine , Piscataway, New Jersey 08854, United States
| | - Meiqian Qian
- Center for Advanced Biotechnology and Medicine , Piscataway, New Jersey 08854, United States
| | - Caifeng Zhao
- Center for Advanced Biotechnology and Medicine , Piscataway, New Jersey 08854, United States
| | - Winnie Xin
- Neurogenetics DNA Diagnostic Laboratory, Department of Neurology, Massachusetts General Hospital, Harvard Medical School , Boston, Massachusetts 02115, United States
| | - Rosemary Barone
- Neurogenetics DNA Diagnostic Laboratory, Department of Neurology, Massachusetts General Hospital, Harvard Medical School , Boston, Massachusetts 02115, United States
| | - Katherine B Sims
- Neurogenetics DNA Diagnostic Laboratory, Department of Neurology, Massachusetts General Hospital, Harvard Medical School , Boston, Massachusetts 02115, United States
| | - Dirk F Moore
- Department of Biostatistics, School of Public Health, Rutgers - The State University of New Jersey , Piscataway, New Jersey 08854, United States
| | - Peter Lobel
- Center for Advanced Biotechnology and Medicine , Piscataway, New Jersey 08854, United States.,Department of Biochemistry and Molecular Biology, Robert-Wood Johnson Medical School, Rutgers Biomedical Health Sciences , Piscataway, New Jersey 08854, United States
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39
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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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40
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Donlin-Asp PG, Rossoll W, Bassell GJ. Spatially and temporally regulating translation via mRNA-binding proteins in cellular and neuronal function. FEBS Lett 2017; 591:1508-1525. [PMID: 28295262 DOI: 10.1002/1873-3468.12621] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/02/2017] [Accepted: 03/03/2017] [Indexed: 12/20/2022]
Abstract
Coordinated regulation of mRNA localization and local translation are essential steps in cellular asymmetry and function. It is increasingly evident that mRNA-binding proteins play critical functions in controlling the fate of mRNA, including when and where translation occurs. In this review, we discuss the robust and complex roles that mRNA-binding proteins play in the regulation of local translation that impact cellular function in vertebrates. First, we discuss the role of local translation in cellular polarity and possible links to vertebrate development and patterning. Next, we discuss the expanding role for local protein synthesis in neuronal development and function, with special focus on how a number of neurological diseases have given us insight into the importance of translational regulation. Finally, we discuss the ever-increasing set of tools to study regulated translation and how these tools will be vital in pushing forward and addressing the outstanding questions in the field.
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Affiliation(s)
- Paul G Donlin-Asp
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA
| | - Wilfried Rossoll
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA.,Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, USA.,Center for Neurodegenerative Disease, Emory University School of Medicine, Atlanta, GA, USA.,Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
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41
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Gainer H, House S, Kim DS, Chin H, Pant HC. Squid Giant Axon Contains Neurofilament Protein mRNA but does not Synthesize Neurofilament Proteins. Cell Mol Neurobiol 2017; 37:475-486. [PMID: 27207029 DOI: 10.1007/s10571-016-0382-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 05/06/2016] [Indexed: 12/16/2022]
Abstract
When isolated squid giant axons are incubated in radioactive amino acids, abundant newly synthesized proteins are found in the axoplasm. These proteins are translated in the adaxonal Schwann cells and subsequently transferred into the giant axon. The question as to whether any de novo protein synthesis occurs in the giant axon itself is difficult to resolve because the small contribution of the proteins possibly synthesized intra-axonally is not easily distinguished from the large amounts of the proteins being supplied from the Schwann cells. In this paper, we reexamine this issue by studying the synthesis of endogenous neurofilament (NF) proteins in the axon. Our laboratory previously showed that NF mRNA and protein are present in the squid giant axon, but not in the surrounding adaxonal glia. Therefore, if the isolated squid axon could be shown to contain newly synthesized NF protein de novo, it could not arise from the adaxonal glia. The results of experiments in this paper show that abundant 3H-labeled NF protein is synthesized in the squid giant fiber lobe containing the giant axon's neuronal cell bodies, but despite the presence of NF mRNA in the giant axon no labeled NF protein is detected in the giant axon. This lends support to the glia-axon protein transfer hypothesis which posits that the squid giant axon obtains newly synthesized protein by Schwann cell transfer and not through intra-axonal protein synthesis, and further suggests that the NF mRNA in the axon is in a translationally repressed state.
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Affiliation(s)
- Harold Gainer
- Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA.
- Marine Biological Laboratory, Woods Hole, MA, 02543, USA.
| | - Shirley House
- Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Marine Biological Laboratory, Woods Hole, MA, 02543, USA
| | - Dong Sun Kim
- Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Marine Biological Laboratory, Woods Hole, MA, 02543, USA
- Department of Anatomy, College of Medicine, Kyungbuk National University, Daegu, South Korea
| | - Hemin Chin
- Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Marine Biological Laboratory, Woods Hole, MA, 02543, USA
- Division of Extramural Research, National Eye Institute, NIH, Bethesda, MD, 20892, USA
| | - Harish C Pant
- Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Marine Biological Laboratory, Woods Hole, MA, 02543, USA
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42
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Korsak LIT, Shepard KA, Akins MR. Cell type-dependent axonal localization of translational regulators and mRNA in mouse peripheral olfactory neurons. J Comp Neurol 2017; 525:2202-2215. [PMID: 28266018 DOI: 10.1002/cne.24199] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 02/14/2017] [Accepted: 02/16/2017] [Indexed: 01/01/2023]
Abstract
Local protein synthesis in mature axons may play a role in synaptic plasticity, axonal arborization, or functional diversity of the circuit. To gain insight into this question, we investigated the axonal localization of translational regulators and associated mRNAs in five parallel olfactory circuits, four in the main olfactory bulb and one in the accessory olfactory bulb. Axons in all four main olfactory bulb circuits exhibited axonal localization of Fragile X granules (FXGs), structures that comprise ribosomes, mRNA, and RNA binding proteins including Fragile X mental retardation protein (FMRP) and the related protein FXR2P. In contrast, FXGs were not seen in axons innervating the accessory olfactory bulb. Similarly, axons innervating the main olfactory bulb, but not the accessory olfactory bulb, contained the FXG-associated mRNA Omp (olfactory marker protein). This differential localization was not explained by circuit-dependent differences in expression of FXG components or Omp, suggesting that other factors must regulate their axonal transport. The specificity of this transport was highlighted by the absence from olfactory axons of the calmodulin transcript Calm1, which is highly expressed in peripheral olfactory neurons at levels equivalent to Omp. Regulation of axonal translation by FMRP may shape the structure and function of the axonal arbor in mature sensory neurons in the main olfactory system but not in the accessory olfactory system.
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Affiliation(s)
- Lulu I T Korsak
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, 19104
| | | | - Michael R Akins
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, 19104.,Department of Neurobiology and Anatomy, Drexel University, Philadelphia, Pennsylvania, 19104
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43
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Neural Progenitor Cells Promote Axonal Growth and Alter Axonal mRNA Localization in Adult Neurons. eNeuro 2017; 4:eN-NWR-0171-16. [PMID: 28197547 PMCID: PMC5291088 DOI: 10.1523/eneuro.0171-16.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 01/13/2017] [Accepted: 01/13/2017] [Indexed: 01/16/2023] Open
Abstract
The inhibitory environment of the spinal cord and the intrinsic properties of neurons prevent regeneration of axons following CNS injury. However, both ascending and descending axons of the injured spinal cord have been shown to regenerate into grafts of embryonic neural progenitor cells (NPCs). Previous studies have shown that grafts composed of glial-restricted progenitors (GRPs) and neural-restricted progenitors (NRPs) can provide a permissive microenvironment for axon growth. We have used cocultures of adult rat dorsal root ganglion (DRG) neurons together with NPCs, which have shown significant enhancement of axon growth by embryonic rat GRP and GRPs/NRPs, both in coculture conditions and when DRGs are exposed to conditioned medium from the NPC cultures. This growth-promoting effect of NPC-conditioned medium was also seen in injury-conditioned neurons. DRGs cocultured with GRPs/NRPs showed altered expression of regeneration-associated genes at transcriptional and post-transcriptional levels. We found that levels of GAP-43 mRNA increased in DRG cell bodies and axons. However, hepcidin antimicrobial peptide (HAMP) mRNA decreased in the cell bodies of DRGs cocultured with GRPs/NRPs, which is distinct from the increase in cell body HAMP mRNA levels seen in DRGs after injury conditioning. Endogenous GAP-43 and β-actin mRNAs as well as reporter RNAs carrying axonally localizing 3'UTRs of these transcripts showed significantly increased levels in distal axons in the DRGs cocultured with GRPs/NRPs. These results indicate that axon growth promoted by NPCs is associated not only with enhanced transcription of growth-associated genes but also can increase localization of some mRNAs into growing axons.
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44
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Tedeschi A, Bradke F. Spatial and temporal arrangement of neuronal intrinsic and extrinsic mechanisms controlling axon regeneration. Curr Opin Neurobiol 2016; 42:118-127. [PMID: 28039763 DOI: 10.1016/j.conb.2016.12.005] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 12/07/2016] [Accepted: 12/08/2016] [Indexed: 01/30/2023]
Abstract
Axon regeneration and neuronal tissue repair varies across animal lineages as well as in the mammalian central and peripheral nervous systems. While the peripheral nervous system retains the ability to self-repair, the majority of axons in the adult mammalian central nervous system (CNS) fail to reactivate intrinsic growth programs after injury. Recent findings, however, suggest that long-distance axon regeneration, neuronal circuit assembly and recovery of functions in the adult mammalian CNS are possible. Here, we discuss our current knowledge of the cell signaling pathways and networks controlling axon regeneration. In addition, we outline a number of combinatorial strategies that include among others microtubule-based treatments to foster regeneration and functional connectivity after CNS trauma.
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Affiliation(s)
- Andrea Tedeschi
- German Center for Neurodegenerative Diseases (DZNE), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
| | - Frank Bradke
- German Center for Neurodegenerative Diseases (DZNE), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
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45
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Gonzalez-Lozano MA, Klemmer P, Gebuis T, Hassan C, van Nierop P, van Kesteren RE, Smit AB, Li KW. Dynamics of the mouse brain cortical synaptic proteome during postnatal brain development. Sci Rep 2016; 6:35456. [PMID: 27748445 PMCID: PMC5066275 DOI: 10.1038/srep35456] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 09/28/2016] [Indexed: 01/04/2023] Open
Abstract
Development of the brain involves the formation and maturation of numerous synapses. This process requires prominent changes of the synaptic proteome and potentially involves thousands of different proteins at every synapse. To date the proteome analysis of synapse development has been studied sparsely. Here, we analyzed the cortical synaptic membrane proteome of juvenile postnatal days 9 (P9), P15, P21, P27, adolescent (P35) and different adult ages P70, P140 and P280 of C57Bl6/J mice. Using a quantitative proteomics workflow we quantified 1560 proteins of which 696 showed statistically significant differences over time. Synaptic proteins generally showed increased levels during maturation, whereas proteins involved in protein synthesis generally decreased in abundance. In several cases, proteins from a single functional molecular entity, e.g., subunits of the NMDA receptor, showed differences in their temporal regulation, which may reflect specific synaptic development features of connectivity, strength and plasticity. SNARE proteins, Snap 29/47 and Stx 7/8/12, showed higher expression in immature animals. Finally, we evaluated the function of Cxadr that showed high expression levels at P9 and a fast decline in expression during neuronal development. Knock down of the expression of Cxadr in cultured primary mouse neurons revealed a significant decrease in synapse density.
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Affiliation(s)
- Miguel A Gonzalez-Lozano
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics &Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Patricia Klemmer
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics &Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Titia Gebuis
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics &Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Chopie Hassan
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden, The Netherlands
| | - Pim van Nierop
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics &Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Ronald E van Kesteren
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics &Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics &Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
| | - Ka Wan Li
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics &Cognitive Research, Neuroscience Campus Amsterdam, VU University, Amsterdam, The Netherlands
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Wu D, Klaw MC, Kholodilov N, Burke RE, Detloff MR, Côté MP, Tom VJ. Expressing Constitutively Active Rheb in Adult Dorsal Root Ganglion Neurons Enhances the Integration of Sensory Axons that Regenerate Across a Chondroitinase-Treated Dorsal Root Entry Zone Following Dorsal Root Crush. Front Mol Neurosci 2016; 9:49. [PMID: 27458339 PMCID: PMC4932115 DOI: 10.3389/fnmol.2016.00049] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 06/07/2016] [Indexed: 11/13/2022] Open
Abstract
While the peripheral branch of dorsal root ganglion neurons (DRG) can successfully regenerate after injury, lesioned central branch axons fail to regrow across the dorsal root entry zone (DREZ), the interface between the dorsal root and the spinal cord. This lack of regeneration is due to the limited regenerative capacity of adult sensory axons and the growth-inhibitory environment at the DREZ, which is similar to that found in the glial scar after a central nervous system (CNS) injury. We hypothesized that transduction of adult DRG neurons using adeno-associated virus (AAV) to express a constitutively-active form of the GTPase Rheb (caRheb) will increase their intrinsic growth potential after a dorsal root crush. Additionally, we posited that if we combined that approach with digestion of upregulated chondroitin sulfate proteoglycans (CSPG) at the DREZ with chondroitinase ABC (ChABC), we would promote regeneration of sensory axons across the DREZ into the spinal cord. We first assessed if this strategy promotes neuritic growth in an in vitro model of the glial scar containing CSPG. ChABC allowed for some regeneration across the once potently inhibitory substrate. Combining ChABC treatment with expression of caRheb in DRG significantly improved this growth. We then determined if this combination strategy also enhanced regeneration through the DREZ after dorsal root crush in adult rats in vivo. After unilaterally crushing C4-T1 dorsal roots, we injected AAV5-caRheb or AAV5-GFP into the ipsilateral C5-C8 DRGs. ChABC or PBS was injected into the ipsilateral dorsal horn at C5-C8 to digest CSPG, for a total of four animal groups (caRheb + ChABC, caRheb + PBS, GFP + ChABC, GFP + PBS). Regeneration was rarely observed in PBS-treated animals, whereas short-distance regrowth across the DREZ was observed in ChABC-treated animals. No difference in axon number or length between the ChABC groups was observed, which may be related to intraganglionic inflammation induced by the injection. ChABC-mediated regeneration is functional, as stimulation of ipsilateral median and ulnar nerves induced neuronal c-Fos expression in deafferented dorsal horn in both ChABC groups. Interestingly, caRheb + ChABC animals had significantly more c-Fos+ nuclei indicating that caRheb expression in DRGs promoted functional synaptogenesis of their axons that regenerated beyond a ChABC-treated DREZ.
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Affiliation(s)
- Di Wu
- Department of Neurobiology and Anatomy, Drexel University College of Medicine Philadelphia, PA, USA
| | - Michelle C Klaw
- Department of Neurobiology and Anatomy, Drexel University College of Medicine Philadelphia, PA, USA
| | - Nikolai Kholodilov
- Department of Neurology, Columbia University in the City of New York New York, NY, USA
| | - Robert E Burke
- Department of Neurology, Columbia University in the City of New YorkNew York, NY, USA; Department of Pathology and Cell Biology, Columbia University in the City of New YorkNew York, NY, USA
| | - Megan R Detloff
- Department of Neurobiology and Anatomy, Drexel University College of Medicine Philadelphia, PA, USA
| | - Marie-Pascale Côté
- Department of Neurobiology and Anatomy, Drexel University College of Medicine Philadelphia, PA, USA
| | - Veronica J Tom
- Department of Neurobiology and Anatomy, Drexel University College of Medicine Philadelphia, PA, USA
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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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Jin LQ, Pennise CR, Rodemer W, Jahn KS, Selzer ME. Protein synthetic machinery and mRNA in regenerating tips of spinal cord axons in lamprey. J Comp Neurol 2016; 524:3614-3640. [PMID: 27120118 DOI: 10.1002/cne.24020] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 02/03/2023]
Abstract
Polyribosomes, mRNA, and other elements of translational machinery have been reported in peripheral nerves and in elongating injured axons of sensory neurons in vitro, primarily in growth cones. Evidence for involvement of local protein synthesis in regenerating central nervous system (CNS) axons is less extensive. We monitored regeneration of back-labeled lamprey spinal axons after spinal cord transection and detected mRNA in axon tips by in situ hybridization and microaspiration of their axoplasm. Poly(A)+mRNA was present in the axon tips, and was more abundant in actively regenerating tips than in static or retracting ones. Target-specific polymerase chain reaction (PCR) and in situ hybridization revealed plentiful mRNA for the low molecular neurofilament subunit and β-tubulin, but very little for β-actin, consistent with the morphology of their tips, which lack filopodia and lamellipodia. Electron microscopy showed ribosomes/polyribosomes in the distal parts of axon tips and in association with vesicle-like membranes, primarily in the tip. In one instance, there were structures with the appearance of rough endoplasmic reticulum. Immunohistochemistry showed patches of ribosomal protein S6 positivity in a similar distribution. The results suggest that local protein synthesis might be involved in the mechanism of axon regeneration in the lamprey spinal cord. J. Comp. Neurol. 524:3614-3640, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Li-Qing Jin
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA, 19140.
| | - Cynthia R Pennise
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA, 19140
| | - William Rodemer
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA, 19140
| | - Kristen S Jahn
- The Children's Hospital of Philadelphia, 1108 Pine Street, Philadelphia, PA, 19107
| | - Michael E Selzer
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA, 19140. .,Department of Neurology, Lewis Katz School of Medicine at Temple University, 3500 North Broad Street, Philadelphia, PA, 19140.
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Bellato HM, Hajj GNM. Translational control by eIF2α in neurons: Beyond the stress response. Cytoskeleton (Hoboken) 2016; 73:551-565. [PMID: 26994324 DOI: 10.1002/cm.21294] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 03/14/2016] [Accepted: 03/14/2016] [Indexed: 12/21/2022]
Abstract
The translation of mRNAs is a tightly controlled process that responds to multiple signaling pathways. In neurons, this control is also exerted locally due to the differential necessity of proteins in axons and dendrites. The phosphorylation of the alpha subunit of the translation initiation factor 2 (eIF2α) is one of the mechanisms of translational control. The phosphorylation of eIF2α has classically been viewed as a stress response, halting translation initiation. However, in the nervous system this type of regulation has been related to other mechanisms besides stress response, such as behavior, memory consolidation and nervous system development. Additionally, neurodegenerative diseases have a major stress component, thus eIF2α phosphorylation plays a preeminent role and its modulation is currently viewed as a new opportunity for therapeutic interventions. This review consolidates current information regarding eIF2α phosphorylation in neurons and its impact in neurodegenerative diseases. © 2016 Wiley Periodicals, Inc.
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Miao L, Yang L, Huang H, Liang F, Ling C, Hu Y. mTORC1 is necessary but mTORC2 and GSK3β are inhibitory for AKT3-induced axon regeneration in the central nervous system. eLife 2016; 5:e14908. [PMID: 27026523 PMCID: PMC4841781 DOI: 10.7554/elife.14908] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/21/2016] [Indexed: 01/11/2023] Open
Abstract
Injured mature CNS axons do not regenerate in mammals. Deletion of PTEN, the negative regulator of PI3K, induces CNS axon regeneration through the activation of PI3K-mTOR signaling. We have conducted an extensive molecular dissection of the cross-regulating mechanisms in axon regeneration that involve the downstream effectors of PI3K, AKT and the two mTOR complexes (mTORC1 and mTORC2). We found that the predominant AKT isoform in CNS, AKT3, induces much more robust axon regeneration than AKT1 and that activation of mTORC1 and inhibition of GSK3β are two critical parallel pathways for AKT-induced axon regeneration. Surprisingly, phosphorylation of T308 and S473 of AKT play opposite roles in GSK3β phosphorylation and inhibition, by which mTORC2 and pAKT-S473 negatively regulate axon regeneration. Thus, our study revealed a complex neuron-intrinsic balancing mechanism involving AKT as the nodal point of PI3K, mTORC1/2 and GSK3β that coordinates both positive and negative cues to regulate adult CNS axon regeneration. DOI:http://dx.doi.org/10.7554/eLife.14908.001 The central nervous system consists of the neurons that make up the brain and spinal cord. An important part of a neuron is the long, slender projection along which electrical signals travel, called the axon. In the central nervous system of mammals, damaged axons cannot regrow, which is why spinal injuries or optic nerve injuries can result in life-long neuronal deficits. Recent studies have found that activating a particular signaling pathway in central nervous system neurons causes their axons to regenerate. A key protein in this pathway is called AKT. Several signaling cascades are triggered by AKT to regulate cell survival and growth, but it was not known how the different branches of the AKT pathway are involved in axon regeneration. Miao, Yang et al. have now investigated AKT’s role in axon regeneration using a range of approaches to manipulate signaling in damaged mouse neurons. This revealed that a particular form of AKT (called AKT3) causes damaged axons to regenerate to a greater extent than other forms of this protein. This response depends on two parallel pathways: one in which AKT3 activates a protein complex called mTORC1, and one where AKT3 inhibits a protein called GSK3β. In addition, another protein complex called mTORC2, which is closely related to mTORC1, helps to inhibit the activity of AKT3 on GSK3β and hence inhibits axon regeneration. These findings reveal that a complex balancing mechanism, with AKT at its center, coordinates the many signals that regulate axon regeneration. Future studies into this system could ultimately help to develop new treatments for brain and spinal injuries. DOI:http://dx.doi.org/10.7554/eLife.14908.002
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Affiliation(s)
- Linqing Miao
- Shriners Hospitals Pediatric Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, United States
| | - Liu Yang
- Shriners Hospitals Pediatric Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, United States
| | - Haoliang Huang
- Shriners Hospitals Pediatric Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, United States
| | - Feisi Liang
- Shriners Hospitals Pediatric Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, United States
| | - Chen Ling
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida College of Medicine, Gainesville, United States
| | - Yang Hu
- Shriners Hospitals Pediatric Research Center, Temple University Lewis Katz School of Medicine, Philadelphia, United States.,Department of Anatomy and Cell Biology, Temple University Lewis Katz School of Medicine, Philadelphia, United States
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