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Gagnon J, Caron V, Tremblay A. SUMOylation of nuclear receptor Nor1/NR4A3 coordinates microtubule cytoskeletal dynamics and stability in neuronal cells. Cell Biosci 2024; 14:91. [PMID: 38997783 DOI: 10.1186/s13578-024-01273-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 07/05/2024] [Indexed: 07/14/2024] Open
Abstract
BACKGROUND Nor1/NR4A3 is a member of the NR4A subfamily of nuclear receptors that play essential roles in regulating gene expression related to development, cell homeostasis and neurological functions. However, Nor1 is still considered an orphan receptor, as its natural ligand remains unclear for mediating transcriptional activation. Yet other activation signals may modulate Nor1 activity, although their precise role in the development and maintenance of the nervous system remains elusive. METHODS We used transcriptional reporter assays, gene expression profiling, protein turnover measurement, and cell growth assays to assess the functional relevance of Nor1 and SUMO-defective variants in neuronal cells. SUMO1 and SUMO2 conjugation to Nor1 were assessed by immunoprecipitation. Tubulin stability was determined by acetylation and polymerization assays, and live-cell fluorescent microscopy. RESULTS Here, we demonstrate that Nor1 undergoes SUMO1 conjugation at Lys-89 within a canonical ψKxE SUMOylation motif, contributing to the complex pattern of Nor1 SUMOylation, which also includes Lys-137. Disruption of Lys-89, thereby preventing SUMO1 conjugation, led to reduced Nor1 transcriptional competence and protein stability, as well as the downregulation of genes involved in cell growth and metabolism, such as ENO3, EN1, and CFLAR, and in microtubule cytoskeleton dynamics, including MAP2 and MAPT, which resulted in reduced survival of neuronal cells. Interestingly, Lys-89 SUMOylation was potentiated in response to nocodazole, a microtubule depolymerizing drug, although this was insufficient to rescue cells from microtubule disruption despite enhanced Nor1 gene expression. Instead, Lys-89 deSUMOylation reduced the expression of microtubule-severing genes like KATNA1, SPAST, and FIGN, and enhanced α-tubulin cellular levels, acetylation, and microfilament organization, promoting microtubule stability and resistance to nocodazole. These effects contrasted with Lys-137 SUMOylation, suggesting distinct regulatory mechanisms based on specific Nor1 input SUMOylation signals. CONCLUSIONS Our study provides novel insights into Nor1 transcriptional signaling competence and identifies a hierarchical mechanism whereby selective Nor1 SUMOylation may govern neuronal cytoskeleton network dynamics and resistance against microtubule disturbances, a condition strongly associated with neurodegenerative diseases.
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Affiliation(s)
- Jonathan Gagnon
- Research Center, CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, Québec, H3T 1C5, Canada
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Montreal, Montréal, Québec, H3T 1J4, Canada
| | - Véronique Caron
- Research Center, CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, Québec, H3T 1C5, Canada
| | - André Tremblay
- Research Center, CHU Sainte-Justine, 3175 Côte Ste-Catherine, Montréal, Québec, H3T 1C5, Canada.
- Department of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Montreal, Montréal, Québec, H3T 1J4, Canada.
- Centre de Recherche en Reproduction et Fertilité, University of Montreal, Saint-Hyacinthe, Québec, J2S 7C6, Canada.
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Montreal, Montréal, Québec, H3T 1J4, Canada.
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Qi L, Chen S, Liao Z, Fan M, Zhang J, Gao Y, Shen J, Sun Y, Wang Q. Comprehensive characterization of Fidgetin on tumor immune microenvironment evaluation and immunotherapy in human hepatocellular carcinoma. Aging (Albany NY) 2024; 16:4445-4468. [PMID: 38421251 PMCID: PMC10968695 DOI: 10.18632/aging.205598] [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: 10/18/2023] [Accepted: 01/29/2024] [Indexed: 03/02/2024]
Abstract
Most cancers have a downregulation of Fidgetin (FIGN), which has been linked to tumor growth. However, there aren't many papers that mention FIGN's connection to hepatocellular carcinoma (HCC). Here, FIGN expression in HCC tissues was markedly reduced as compared to nearby normal liver tissues. According to univariate and multivariate Cox regression, it served as an independent predictor of survival outcomes. Patients with high levels of FIGN expression had a worse outcome. FIGN was shown to be engaged in immune-related pathways and to have a positive correlation with immunological score and immune cells according to KEGG pathway analysis. In HCC patients, FIGN was substantially linked with immunological checkpoints and the hot tumor state. Additionally, immunotherapy and chemotherapy showed a significant therapeutic response in HCC patients with low FIGN expression. This research revealed that FIGN expression was tightly related to hepatoma immunity and might be employed as a biomarker to predict patient prognosis and guide medication.
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Affiliation(s)
- Longju Qi
- Laboratory Animal Center, Medical School, Nantong University, Nantong, China
- Affiliated Nantong Hospital 3 of Nantong University, Nantong University, Nantong, China
| | - Shiyuan Chen
- Laboratory Animal Center, Medical School, Nantong University, Nantong, China
| | - Zehua Liao
- Laboratory Animal Center, Medical School, Nantong University, Nantong, China
| | - Mengjie Fan
- Laboratory Animal Center, Medical School, Nantong University, Nantong, China
| | - Jiayi Zhang
- Laboratory Animal Center, Medical School, Nantong University, Nantong, China
| | - Yuan Gao
- Laboratory Animal Center, Medical School, Nantong University, Nantong, China
| | - Jiabao Shen
- Laboratory Animal Center, Medical School, Nantong University, Nantong, China
| | - Yuyu Sun
- Affiliated Nantong Hospital 3 of Nantong University, Nantong University, Nantong, China
| | - Qinghua Wang
- Laboratory Animal Center, Medical School, Nantong University, Nantong, China
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3
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Smart K, Sharp DJ. The fidgetin family: Shaking things up among the microtubule-severing enzymes. Cytoskeleton (Hoboken) 2024; 81:151-166. [PMID: 37823563 DOI: 10.1002/cm.21799] [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: 07/14/2023] [Revised: 09/23/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023]
Abstract
The microtubule cytoskeleton is required for several crucial cellular processes, including chromosome segregation, cell polarity and orientation, and intracellular transport. These functions rely on microtubule stability and dynamics, which are regulated by microtubule-binding proteins (MTBPs). One such type of regulator is the microtubule-severing enzymes (MSEs), which are ATPases Associated with Diverse Cellular Activities (AAA+ ATPases). The most recently identified family are the fidgetins, which contain three members: fidgetin, fidgetin-like 1 (FL1), and fidgetin-like 2 (FL2). Of the three known MSE families, the fidgetins have the most diverse range of functions in the cell, spanning mitosis/meiosis, development, cell migration, DNA repair, and neuronal function. Furthermore, they offer intriguing novel therapeutic targets for cancer, cardiovascular disease, and wound healing. In the two decades since their first report, there has been great progress in our understanding of the fidgetins; however, there is still much left unknown about this unusual family. This review aims to consolidate the present body of knowledge of the fidgetin family of MSEs and to inspire deeper exploration into the fidgetins and the MSEs as a whole.
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Affiliation(s)
- Karishma Smart
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - David J Sharp
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
- Microcures, Inc., Bronx, New York, USA
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Ma C, Wang J, Tu Q, Bo W, Hu Z, Zhuo R, Wu R, Dong Z, Qiang L, Liu Y, Liu M. Fidgetin interacting with microtubule end binding protein EB3 affects axonal regrowth in spinal cord injury. Neural Regen Res 2023; 18:2727-2732. [PMID: 37449637 DOI: 10.4103/1673-5374.373716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/18/2023] Open
Abstract
Fidgetin, a microtubule-severing enzyme, regulates neurite outgrowth, axonal regeneration, and cell migration by trimming off the labile domain of microtubule polymers. Because maintenance of the microtubule labile domain is essential for axon initiation, elongation, and navigation, it is of interest to determine whether augmenting the microtubule labile domain via depletion of fidgetin serves as a therapeutic approach to promote axonal regrowth in spinal cord injury. In this study, we constructed rat models of spinal cord injury and sciatic nerve injury. Compared with spinal cord injury, we found that expression level of tyrosinated microtubules in the labile portion of microtubules continuously increased, whereas fidgetin decreased after peripheral nerve injury. Depletion of fidgetin enhanced axon regeneration after spinal cord injury, whereas expression level of end binding protein 3 (EB3) markedly increased. Next, we performed RNA interference to knockdown EB3 or fidgetin. We found that deletion of EB3 did not change fidgetin expression. Conversely, deletion of fidgetin markedly increased expression of tyrosinated microtubules and EB3. Deletion of fidgetin increased the amount of EB3 at the end of neurites and thereby increased the level of tyrosinated microtubules. Finally, we deleted EB3 and overexpressed fidgetin. We found that fidgetin trimmed tyrosinated tubulins by interacting with EB3. When fidgetin was deleted, the labile portion of microtubules was elongated, and as a result the length of axons and number of axon branches were increased. These findings suggest that fidgetin can be used as a novel therapeutic target to promote axonal regeneration after spinal cord injury. Furthermore, they reveal an innovative mechanism by which fidgetin preferentially severs labile microtubules.
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Affiliation(s)
- Chao Ma
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University; Medical School of Nantong University, Nantong, Jiangsu Province, China
| | - Junpei Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu Province, China
| | - Qifeng Tu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu Province, China
| | - Weijuan Bo
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu Province, China
| | - Zunlu Hu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu Province, China
| | - Run Zhuo
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu Province, China
| | - Ronghua Wu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu Province, China
| | - Zhangji Dong
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu Province, China
| | - Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Yan Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu Province, China
| | - Mei Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Nantong University, Nantong, Jiangsu Province, China
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Atkins M, Nicol X, Fassier C. Microtubule remodelling as a driving force of axon guidance and pruning. Semin Cell Dev Biol 2023; 140:35-53. [PMID: 35710759 DOI: 10.1016/j.semcdb.2022.05.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/26/2022] [Accepted: 05/31/2022] [Indexed: 01/28/2023]
Abstract
The establishment of neuronal connectivity relies on the microtubule (MT) cytoskeleton, which provides mechanical support, roads for axonal transport and mediates signalling events. Fine-tuned spatiotemporal regulation of MT functions by tubulin post-translational modifications and MT-associated proteins is critical for the coarse wiring and subsequent refinement of neuronal connectivity. The defective regulation of these processes causes a wide range of neurodevelopmental disorders associated with connectivity defects. This review focuses on recent studies unravelling how MT composition, post-translational modifications and associated proteins influence MT functions in axon guidance and/or pruning to build functional neuronal circuits. We here summarise experimental evidence supporting the key role of this network as a driving force for growth cone steering and branch-specific axon elimination. We further provide a global overview of the MT-interactors that tune developing axon behaviours, with a special emphasis on their emerging versatility in the regulation of MT dynamics/structure. Recent studies establishing the key and highly selective role of the tubulin code in the regulation of MT functions in axon pathfinding are also reported. Finally, our review highlights the emerging molecular links between these MT regulation processes and guidance signals that wire the nervous system.
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Affiliation(s)
- Melody Atkins
- INSERM, UMR-S 1270, Institut du Fer à Moulin, Sorbonne Université, F-75005 Paris, France
| | - Xavier Nicol
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, F-75012 Paris, France
| | - Coralie Fassier
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, F-75012 Paris, France.
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Carmona B, Marinho HS, Matos CL, Nolasco S, Soares H. Tubulin Post-Translational Modifications: The Elusive Roles of Acetylation. BIOLOGY 2023; 12:biology12040561. [PMID: 37106761 PMCID: PMC10136095 DOI: 10.3390/biology12040561] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 03/27/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023]
Abstract
Microtubules (MTs), dynamic polymers of α/β-tubulin heterodimers found in all eukaryotes, are involved in cytoplasm spatial organization, intracellular transport, cell polarity, migration and division, and in cilia biology. MTs functional diversity depends on the differential expression of distinct tubulin isotypes and is amplified by a vast number of different post-translational modifications (PTMs). The addition/removal of PTMs to α- or β-tubulins is catalyzed by specific enzymes and allows combinatory patterns largely enriching the distinct biochemical and biophysical properties of MTs, creating a code read by distinct proteins, including microtubule-associated proteins (MAPs), which allow cellular responses. This review is focused on tubulin-acetylation, whose cellular roles continue to generate debate. We travel through the experimental data pointing to α-tubulin Lys40 acetylation role as being a MT stabilizer and a typical PTM of long lived MTs, to the most recent data, suggesting that Lys40 acetylation enhances MT flexibility and alters the mechanical properties of MTs, preventing MTs from mechanical aging characterized by structural damage. Additionally, we discuss the regulation of tubulin acetyltransferases/desacetylases and their impacts on cell physiology. Finally, we analyze how changes in MT acetylation levels have been found to be a general response to stress and how they are associated with several human pathologies.
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Affiliation(s)
- Bruno Carmona
- Centro de Química Estrutural, Institute of Molecular Sciences, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Av. D. João II, Lote 4.69.01, 1990-096 Lisboa, Portugal
| | - H Susana Marinho
- Centro de Química Estrutural, Institute of Molecular Sciences, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Catarina Lopes Matos
- Centro de Química Estrutural, Institute of Molecular Sciences, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - Sofia Nolasco
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Av. D. João II, Lote 4.69.01, 1990-096 Lisboa, Portugal
- CIISA-Centro de Investigação Interdisciplinar em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal
| | - Helena Soares
- Centro de Química Estrutural, Institute of Molecular Sciences, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
- Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Av. D. João II, Lote 4.69.01, 1990-096 Lisboa, Portugal
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Fidgetin impacts axonal growth and branching in a local mTOR signal dependent manner. Exp Neurol 2023; 361:114315. [PMID: 36586551 DOI: 10.1016/j.expneurol.2022.114315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 12/14/2022] [Accepted: 12/26/2022] [Indexed: 12/31/2022]
Abstract
Neurons require a constant increase in protein synthesis during axonal growth and regeneration. AKT-mTOR is a central pathway for mammalian cell survival and regeneration. Fidgetin (Fign) is an ATP-dependent microtubule (MT)-severing enzyme whose functions are associated with neurite outgrowth, axon regeneration and cell migration. Although most previous studies have indicated that depletion of Fign is involved in those biological activities by increasing labile MT mass, it remains unknown whether mTOR activation contributes to this process. Here, we showed that depletion of Fign enhanced p-mTOR/p-S6K activation, and the mTOR inhibitor Rapamycin inhibited axon outgrowth and p-rpS6 activation. We then investigated the effects of neuronal-specific Fign deletion in a rat spinal cord hemisection model by injecting syn-GFP Fign shRNA virus. BBB values revealed an improvement in functional recovery. The p-mTOR was activated along with neuronal Fign depletion. The syn-mCherry virus showed more sprouting neurites entering the injury region, which was confirmed by immunostaining GAP43 protein. Further, we showed that Fign siRNA treatment promoted axon outgrowth and branching, whose underlying mechanism was firstly attributed to local activation of the mTOR pathway, and increased MT dynamicity. Finally, considering L-leucine, promotes axonal growth and neuronal survival, we applied L-leucine with Fign depletion after spinal cord injury or in chondroitin sulfate proteoglycan inhibitory molecules. The phenomenon of synergistically augmented axon regeneration was observed. In summary, our results indicated a novel local mTOR pathway for fidgetin to impact axon growth and provided a combined strategy in SCI.
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Costa G, Ribeiro FF, Sebastião AM, Muir EM, Vaz SH. Bridging the gap of axonal regeneration in the central nervous system: A state of the art review on central axonal regeneration. Front Neurosci 2022; 16:1003145. [PMID: 36440273 PMCID: PMC9682039 DOI: 10.3389/fnins.2022.1003145] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/19/2022] [Indexed: 08/26/2023] Open
Abstract
Neuronal regeneration in the central nervous system (CNS) is an important field of research with relevance to all types of neuronal injuries, including neurodegenerative diseases. The glial scar is a result of the astrocyte response to CNS injury. It is made up of many components creating a complex environment in which astrocytes play various key roles. The glial scar is heterogeneous, diverse and its composition depends upon the injury type and location. The heterogeneity of the glial scar observed in different situations of CNS damage and the consequent implications for axon regeneration have not been reviewed in depth. The gap in this knowledge will be addressed in this review which will also focus on our current understanding of central axonal regeneration and the molecular mechanisms involved. The multifactorial context of CNS regeneration is discussed, and we review newly identified roles for components previously thought to solely play an inhibitory role in central regeneration: astrocytes and p75NTR and discuss their potential and relevance for deciding therapeutic interventions. The article ends with a comprehensive review of promising new therapeutic targets identified for axonal regeneration in CNS and a discussion of novel ways of looking at therapeutic interventions for several brain diseases and injuries.
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Affiliation(s)
- Gonçalo Costa
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Faculdade de Medicina, Universidade do Porto, Porto, Portugal
| | - Filipa F. Ribeiro
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Ana M. Sebastião
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Elizabeth M. Muir
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Sandra H. Vaz
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
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Kwon JT, Kim Y, Choi S, Yoon BL, Kim HS, Shim I, Sul D. Pulmonary Toxicity and Proteomic Analysis in Bronchoalveolar Lavage Fluids and Lungs of Rats Exposed to Copper Oxide Nanoparticles. Int J Mol Sci 2022; 23:13265. [PMID: 36362054 PMCID: PMC9655042 DOI: 10.3390/ijms232113265] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 10/14/2022] [Accepted: 10/25/2022] [Indexed: 07/21/2023] Open
Abstract
Copper oxide nanoparticles (CuO NPs) were intratracheally instilled into lungs at concentrations of 0, 0.15, and 1.5 mg/kg bodyweight to 7-week-old Sprague-Dawley rats. The cytotoxicity, immunotoxicity, and oxidative stress were evaluated, followed by proteomic analysis of bronchoalveolar lavage fluid (BALF) and lungs of rats. The CuO NPs-exposed groups revealed dose-dependent increases in total cells, polymorphonuclear leukocytes, lactate dyhydrogenase, and total protein levels in BALF. Inflammatory cytokines, including macrophage inflammatory protein-2 and tumor necrosis factor-α, were increased in the CuO NPs-treated groups. The expression levels of catalase, glutathione peroxidase-1, and peroxiredoxin-2 were downregulated, whereas that of superoxide dismutase-2 was upregulated in the CuO NPs-exposed groups. Five heat shock proteins were downregulated in rats exposed to high concentrations of CuO NPs. In proteomic analysis, 17 proteins were upregulated or downregulated, and 6 proteins were validated via Western blot analysis. Significant upregulation of 3-hydroxy-3-methylglutaryl-CoA synthase and fidgetin-like 1 and downregulation of annexin II, HSP 47 and proteasome α1 occurred in the CuO NPs exposed groups. Taken together, this study provides additional insight into pulmonary cytotoxicity and immunotoxicity as well as oxidative stress in rats exposed to CuO NPs. Proteomic analysis revealed potential toxicological biomarkers of CuO NPs, which also reveals the toxicity mechanisms of CuO NPs.
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Affiliation(s)
- Jung-Taek Kwon
- Environmental Health Research Department, National Institute of Environmental Research, Incheon 22689, Korea
| | - Yoonjin Kim
- Environmental Health Research Department, National Institute of Environmental Research, Incheon 22689, Korea
| | - Seonyoung Choi
- Graduate School of Medicine, Korea University, 73 Inchon-ro, Sungbuk-ku, Seoul 136-705, Korea
| | - Byung-ll Yoon
- College of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea
| | - Hyun-Sook Kim
- Department of Biomedical Laboratory Science, College of Health Science, Cheongju University, Cheongju 28503, Korea
| | - Ilseob Shim
- Environmental Health Research Department, National Institute of Environmental Research, Incheon 22689, Korea
| | - Donggeun Sul
- Graduate School of Medicine, Korea University, 73 Inchon-ro, Sungbuk-ku, Seoul 136-705, Korea
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Costa AC, Sousa MM. The Role of Spastin in Axon Biology. Front Cell Dev Biol 2022; 10:934522. [PMID: 35865632 PMCID: PMC9294387 DOI: 10.3389/fcell.2022.934522] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 06/07/2022] [Indexed: 12/05/2022] Open
Abstract
Neurons are highly polarized cells with elaborate shapes that allow them to perform their function. In neurons, microtubule organization—length, density, and dynamics—are essential for the establishment of polarity, growth, and transport. A mounting body of evidence shows that modulation of the microtubule cytoskeleton by microtubule-associated proteins fine tunes key aspects of neuronal cell biology. In this respect, microtubule severing enzymes—spastin, katanin and fidgetin—a group of microtubule-associated proteins that bind to and generate internal breaks in the microtubule lattice, are emerging as key modulators of the microtubule cytoskeleton in different model systems. In this review, we provide an integrative view on the latest research demonstrating the key role of spastin in neurons, specifically in the context of axonal cell biology. We focus on the function of spastin in the regulation of microtubule organization, and axonal transport, that underlie its importance in the intricate control of axon growth, branching and regeneration.
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Affiliation(s)
- Ana Catarina Costa
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular (IBMC), Instituto de Investigação e Inovação Em Saúde (i3S), University of Porto, Porto, Portugal
- Graduate Program in Molecular and Cell Biology, Instituto de Ciências Biomédicas Abel Salazar (ICBAS), University of Porto, Porto, Portugal
- *Correspondence: Ana Catarina Costa, ; Monica Mendes Sousa,
| | - Monica Mendes Sousa
- Nerve Regeneration Group, Instituto de Biologia Molecular e Celular (IBMC), Instituto de Investigação e Inovação Em Saúde (i3S), University of Porto, Porto, Portugal
- *Correspondence: Ana Catarina Costa, ; Monica Mendes Sousa,
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Rolls MM. Principles of microtubule polarity in linear cells. Dev Biol 2022; 483:112-117. [PMID: 35016908 PMCID: PMC10071391 DOI: 10.1016/j.ydbio.2022.01.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 01/06/2022] [Indexed: 01/30/2023]
Abstract
The microtubule cytoskeleton is critical for maintenance of long and long-lived neurons. The overlapping array of microtubules extends from the major site of synthesis in the cell body to the far reaches of axons and dendrites. New materials are transported from the cell body along these neuronal roads by motor proteins, and building blocks and information about the state of affairs in other parts of the cell are returned by motors moving in the opposite direction. As motor proteins walk only in one direction along microtubules, the combination of correct motor and correctly oriented microtubules is essential for moving cargoes in the right direction. In this review, we focus on how microtubule polarity is established and maintained in neurons. At first thought, it seems that figuring out how microtubules are organized in neurons should be simple. After all, microtubules are essentially sticks with a slow-growing minus end and faster-growing plus end, and arranging sticks within the constrained narrow tubes of axons and dendrites should be straightforward. It is therefore quite surprising how many mechanisms contribute to making sure they are arranged in the correct polarity. Some of these mechanisms operate to generate plus-end-out polarity of axons, and others control mixed or minus-end-out dendrites.
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Affiliation(s)
- Melissa M Rolls
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
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12
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Leong JCK, Li Y, Uesaka M, Uchida Y, Omori A, Hao M, Wan W, Dong Y, Ren Y, Zhang S, Zeng T, Wang F, Chen L, Wessel G, Livingston BT, Bradham C, Wang W, Irie N. Derivedness Index for Estimating Degree of Phenotypic Evolution of Embryos: A Study of Comparative Transcriptomic Analyses of Chordates and Echinoderms. Front Cell Dev Biol 2021; 9:749963. [PMID: 34900995 PMCID: PMC8661034 DOI: 10.3389/fcell.2021.749963] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/03/2021] [Indexed: 11/13/2022] Open
Abstract
Species retaining ancestral features, such as species called living fossils, are often regarded as less derived than their sister groups, but such discussions are usually based on qualitative enumeration of conserved traits. This approach creates a major barrier, especially when quantifying the degree of phenotypic evolution or degree of derivedness, since it focuses only on commonly shared traits, and newly acquired or lost traits are often overlooked. To provide a potential solution to this problem, especially for inter-species comparison of gene expression profiles, we propose a new method named "derivedness index" to quantify the degree of derivedness. In contrast to the conservation-based approach, which deals with expressions of commonly shared genes among species being compared, the derivedness index also considers those that were potentially lost or duplicated during evolution. By applying our method, we found that the gene expression profiles of penta-radial phases in echinoderm tended to be more highly derived than those of the bilateral phase. However, our results suggest that echinoderms may not have experienced much larger modifications to their developmental systems than chordates, at least at the transcriptomic level. In vertebrates, we found that the mid-embryonic and organogenesis stages were generally less derived than the earlier or later stages, indicating that the conserved phylotypic period is also less derived. We also found genes that potentially explain less derivedness, such as Hox genes. Finally, we highlight technical concerns that may influence the measured transcriptomic derivedness, such as read depth and library preparation protocols, for further improvement of our method through future studies. We anticipate that this index will serve as a quantitative guide in the search for constrained developmental phases or processes.
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Affiliation(s)
- Jason Cheok Kuan Leong
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Yongxin Li
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Masahiro Uesaka
- RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Yui Uchida
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.,Universal Biology Institute, The University of Tokyo, Tokyo, Japan
| | - Akihito Omori
- Sado Island Center for Ecological Sustainability, Niigata University, Niigata, Japan
| | - Meng Hao
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Wenting Wan
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Yang Dong
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Yandong Ren
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Si Zhang
- Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Tao Zeng
- Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Fayou Wang
- Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Luonan Chen
- Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.,Key Laboratory of Systems Biology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Hangzhou, China
| | - Gary Wessel
- Providence Institute of Molecular Oogenesis, Brown University, Providence, RI, United States
| | - Brian T Livingston
- Department of Biological Sciences, California State University, Long Beach, CA, United States
| | - Cynthia Bradham
- Department of Biology, Boston University, Boston, MA, United States
| | - Wen Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China.,School of Ecology and Environment, Northwestern Polytechnical University, Xi'an, China
| | - Naoki Irie
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan.,Universal Biology Institute, The University of Tokyo, Tokyo, Japan
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13
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Bu S, Yong WL, Lim BJW, Kondo S, Yu F. A systematic analysis of microtubule-destabilizing factors during dendrite pruning in Drosophila. EMBO Rep 2021; 22:e52679. [PMID: 34338441 DOI: 10.15252/embr.202152679] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 07/10/2021] [Accepted: 07/12/2021] [Indexed: 11/09/2022] Open
Abstract
It has long been thought that microtubule disassembly, one of the earliest cellular events, contributes to neuronal pruning and neurodegeneration in development and disease. However, how microtubule disassembly drives neuronal pruning remains poorly understood. Here, we conduct a systematic investigation of various microtubule-destabilizing factors and identify exchange factor for Arf6 (Efa6) and Stathmin (Stai) as new regulators of dendrite pruning in ddaC sensory neurons during Drosophila metamorphosis. We show that Efa6 is both necessary and sufficient to regulate dendrite pruning. Interestingly, Efa6 and Stai facilitate microtubule turnover and disassembly prior to dendrite pruning without compromising the minus-end-out microtubule orientation in dendrites. Moreover, our pharmacological and genetic manipulations strongly support a key role of microtubule disassembly in promoting dendrite pruning. Thus, this systematic study highlights the importance of two selective microtubule destabilizers in dendrite pruning and substantiates a causal link between microtubule disassembly and neuronal pruning.
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Affiliation(s)
- Shufeng Bu
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Wei Lin Yong
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
| | - Bryan Jian Wei Lim
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Shu Kondo
- Invertebrate Genetics Laboratory, National Institute of Genetics, Shizuoka, Japan
| | - Fengwei Yu
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
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14
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Hagita A, Wada-Kakuda S, Nobuhara M, Kakuda N, Miyasaka T. Quantitative fractionation of tissue microtubules with distinct biochemical properties reflecting their stability and lability. Biochem Biophys Res Commun 2021; 560:186-191. [PMID: 33992960 DOI: 10.1016/j.bbrc.2021.04.117] [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: 03/30/2021] [Accepted: 04/27/2021] [Indexed: 10/21/2022]
Abstract
Microtubules form a major cytoskeleton and exhibit dynamic instability through the repetitive polymerization/depolymerization of tubulin dimers. Although microtubule stability should be precisely controlled to maintain various cellular functions, it has been difficult to assess its status in vivo. Here, we propose a tubulin fractionation method reflecting the stability of microtubules in mouse tissues. Analyses of tubulin fractionated by two-step of ultracentrifugation demonstrated three distinct pools of tubulin, that appeared to be stable microtubule, labile microtubule, and free tubulin. Using this method, we were able to show the specific binding of different microtubule-associated proteins onto each pool of microtubules. Also, there were clear differences in the population of stable microtubule among tissues depending on the proliferative capacity of the constituent cells. These findings indicate that this method is useful for broad analysis of microtubule stability in physiological and pathological conditions.
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Affiliation(s)
- Ayaka Hagita
- Department of Neuropathology, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, 610-0394, Japan; Center for Research in Neurodegenerative Diseases, Doshisha University, Kyoto 610-0394, Japan
| | - Satoko Wada-Kakuda
- Department of Neuropathology, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, 610-0394, Japan
| | - Mika Nobuhara
- Department of Neuropathology, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, 610-0394, Japan
| | - Nobuto Kakuda
- Center for Research in Neurodegenerative Diseases, Doshisha University, Kyoto 610-0394, Japan
| | - Tomohiro Miyasaka
- Department of Neuropathology, Faculty of Life and Medical Sciences, Doshisha University, Kyoto, 610-0394, Japan; Center for Research in Neurodegenerative Diseases, Doshisha University, Kyoto 610-0394, Japan.
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15
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Mani N, Wijeratne SS, Subramanian R. Micron-scale geometrical features of microtubules as regulators of microtubule organization. eLife 2021; 10:e63880. [PMID: 34114950 PMCID: PMC8195601 DOI: 10.7554/elife.63880] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 06/02/2021] [Indexed: 12/20/2022] Open
Abstract
The organization of micron-sized, multi-microtubule arrays from individual microtubules is essential for diverse cellular functions. The microtubule polymer is largely viewed as a passive building block during the organization process. An exception is the 'tubulin code' where alterations to tubulin at the amino acid level can influence the activity of microtubule-associated proteins. Recent studies reveal that micron-scale geometrical features of individual microtubules and polymer networks, such as microtubule length, overlap length, contact angle, and lattice defects, can also regulate the activity of microtubule-associated proteins and modulate polymer dynamics. We discuss how the interplay between such geometrical properties of the microtubule lattice and the activity of associated proteins direct multiple aspects of array organization, from microtubule nucleation and coalignment to specification of array dimensions and remodeling of dynamic networks. The mechanisms reviewed here highlight micron-sized features of microtubules as critical parameters to be routinely investigated in the study of microtubule self-organization.
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Affiliation(s)
- Nandini Mani
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | - Sithara S Wijeratne
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
| | - Radhika Subramanian
- Department of Molecular Biology, Massachusetts General HospitalBostonUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
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16
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Baker L, Tar M, Kramer AH, Villegas GA, Charafeddine RA, Vafaeva O, Nacharaju P, Friedman J, Davies KP, Sharp DJ. Fidgetin-like 2 negatively regulates axonal growth and can be targeted to promote functional nerve regeneration. JCI Insight 2021; 6:138484. [PMID: 33872220 PMCID: PMC8262307 DOI: 10.1172/jci.insight.138484] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 04/01/2021] [Indexed: 02/05/2023] Open
Abstract
The microtubule (MT) cytoskeleton plays a critical role in axon growth and guidance. Here, we identify the MT-severing enzyme fidgetin-like 2 (FL2) as a negative regulator of axon regeneration and a therapeutic target for promoting nerve regeneration after injury. Genetic knockout of FL2 in cultured adult dorsal root ganglion neurons resulted in longer axons and attenuated growth cone retraction in response to inhibitory molecules. Given the axonal growth-promoting effects of FL2 depletion in vitro, we tested whether FL2 could be targeted to promote regeneration in a rodent model of cavernous nerve (CN) injury. The CNs are parasympathetic nerves that regulate blood flow to the penis, which are commonly damaged during radical prostatectomy (RP), resulting in erectile dysfunction (ED). Application of FL2-siRNA after CN injury significantly enhanced functional nerve recovery. Remarkably, following bilateral nerve transection, visible and functional nerve regeneration was observed in 7 out of 8 animals treated with FL2-siRNA, while no control-treated animals exhibited regeneration. These studies identify FL2 as a promising therapeutic target for enhancing regeneration after peripheral nerve injury and for mitigating neurogenic ED after RP - a condition for which, at present, only poor treatment options exist.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - David J. Sharp
- Department of Physiology and Biophysics
- Dominick P. Purpura Department of Neuroscience, and
- Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, New York, USA
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17
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Dong Z, Chen X, Li Y, Zhuo R, Lai X, Liu M. Microtubule Severing Protein Fignl2 Contributes to Endothelial and Neuronal Branching in Zebrafish Development. Front Cell Dev Biol 2021; 8:593234. [PMID: 33585441 PMCID: PMC7873885 DOI: 10.3389/fcell.2020.593234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 12/21/2020] [Indexed: 11/13/2022] Open
Abstract
Previously, fidgetin (fign) and its family members fidgetin-like 1 (fignl1) and fidgetin-like 2 (fignl2) were found to be highly expressed during zebrafish brain development, suggesting their functions in the nervous system. In this study, we report the effects of loss-of-function of these genes on development. We designed and identified single-guide RNAs targeted to generate fign, fignl1, and fignl2 mutants and then observed the overall morphological and behavioral changes. Our findings showed that while fign and fignl1 null mutants displayed no significant defects, fignl2 null zebrafish mutants displayed pericardial edema, reduced heart rate, and smaller eyes; fignl2 null mutants responded to the light-darkness shift with a lower swimming velocity. fignl2 mRNAs were identified in vascular endothelial cells by in situ hybridization and re-analysis of an online dataset of single-cell RNAseq results. Finally, we used morpholino oligonucleotides to confirm that fignl2 knockdown resulted in severe heart edema, which was caused by abnormal vascular branching. The zebrafish fignl2 morphants also showed longer axonal length and more branches of caudal primary neurons. Taken together, we summarize that Fignl2 functions on cellular branches in endothelial cells and neurons. This study reported for the first time that the microtubule-severing protein Fignl2 contributes to cell branching during development.
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Affiliation(s)
- Zhangji Dong
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Xu Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Yuanyuan Li
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Run Zhuo
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Xiaona Lai
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Mei Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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18
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Wu D, Jin Y, Shapiro TM, Hinduja A, Baas PW, Tom VJ. Chronic neuronal activation increases dynamic microtubules to enhance functional axon regeneration after dorsal root crush injury. Nat Commun 2020; 11:6131. [PMID: 33257677 PMCID: PMC7705672 DOI: 10.1038/s41467-020-19914-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 11/05/2020] [Indexed: 12/26/2022] Open
Abstract
After a dorsal root crush injury, centrally-projecting sensory axons fail to regenerate across the dorsal root entry zone (DREZ) to extend into the spinal cord. We find that chemogenetic activation of adult dorsal root ganglion (DRG) neurons improves axon growth on an in vitro model of the inhibitory environment after injury. Moreover, repeated bouts of daily chemogenetic activation of adult DRG neurons for 12 weeks post-crush in vivo enhances axon regeneration across a chondroitinase-digested DREZ into spinal gray matter, where the regenerating axons form functional synapses and mediate behavioral recovery in a sensorimotor task. Neuronal activation-mediated axon extension is dependent upon changes in the status of tubulin post-translational modifications indicative of highly dynamic microtubules (as opposed to stable microtubules) within the distal axon, illuminating a novel mechanism underlying stimulation-mediated axon growth. We have identified an effective combinatory strategy to promote functionally-relevant axon regeneration of adult neurons into the CNS after injury.
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Affiliation(s)
- Di Wu
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Ying Jin
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Tatiana M Shapiro
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Abhishek Hinduja
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Veronica J Tom
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, PA, USA.
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19
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Dong Z, Li Y, Chen X, Lai X, Liu M. A comparative study of the expression patterns of Fign family members in zebrafish embryonic development. Comp Biochem Physiol B Biochem Mol Biol 2020; 251:110522. [PMID: 33069857 DOI: 10.1016/j.cbpb.2020.110522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/07/2020] [Accepted: 10/09/2020] [Indexed: 10/23/2022]
Abstract
During development, highly dynamic reconstruction of microtubules is involved in many cellular processes, including cell division, migration, morphological changes, and material transportation within cells. Microtubule severing proteins (MSPs), with the function of cutting microtubules into short parts, are important regulators in the reconstruction of microtubule arrays. Fidgetin (fign) and its family members fidgetin like 1 (fignl1) and fignl2 are MSPs, and knowledge on the expression patterns of fign family members will benefit our understanding of their primary roles in one specific stage during development. In this study, we compared the evolutionary relationships of fign family members and found that fignl2 is closer to fign than fignl1. We utilized the zebrafish model and in situ hybridization (ISH) to parallelly identify the expression features of fign family members. Our findings revealed that before 12 h post fertilization (hpf), the expression patterns of fign and fignl1 and fignl2 genes were similar, but differences arose thereafter. Fignl2 transcripts were present in more tissues and organs of zebrafish after 12 hpf and potentially exhibited more ubiquitous functions. This study is the first to assess systematic comparable data on the expression patterns of fign family members during development.
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Affiliation(s)
- Zhangji Dong
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong Jiangsu 226001, China
| | - Yuanyuan Li
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong Jiangsu 226001, China
| | - Xu Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong Jiangsu 226001, China
| | - Xiaona Lai
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong Jiangsu 226001, China
| | - Mei Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong Jiangsu 226001, China.
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20
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Rolls MM, Thyagarajan P, Feng C. Microtubule dynamics in healthy and injured neurons. Dev Neurobiol 2020; 81:321-332. [PMID: 32291942 DOI: 10.1002/dneu.22746] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/22/2020] [Accepted: 04/08/2020] [Indexed: 12/28/2022]
Abstract
Most neurons must last a lifetime and their microtubule cytoskeleton is an important contributor to their longevity. Neurons have some of the most stable microtubules of all cells, but the tip of every microtubule remains dynamic and, although requiring constant GTP consumption, microtubules are always being rebuilt. While some ongoing level of rebuilding always occurs, overall microtubule stability can be modulated in response to injury and stress as well as the normal developmental process of pruning. Specific microtubule severing proteins act in different contexts to increase microtubule dynamicity and promote degeneration and pruning. After axon injury, complex changes in dynamics occur and these are important for both neuroprotection induced by injury and subsequent outgrowth of a new axon. Understanding how microtubule dynamics is modulated in different scenarios, as well as the impact of the changes in stability, is an important avenue to explore for development of strategies to promote neuroprotection and regeneration.
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Affiliation(s)
- Melissa M Rolls
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Pankajam Thyagarajan
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Chengye Feng
- Biochemistry and Molecular Biology and Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
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21
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Li J, Wu F, Cheng L, Zhang J, Cha C, Chen L, Feng T, Zhang J, Guo G. A nuclear localization signal is required for the nuclear translocation of Fign and its microtubule‑severing function. Mol Med Rep 2020; 21:2367-2374. [PMID: 32236575 PMCID: PMC7185285 DOI: 10.3892/mmr.2020.11040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 03/04/2020] [Indexed: 01/21/2023] Open
Abstract
It is commonly known that the specific function of a given ATPase associated with diverse cellular activities protein (i.e., a member of the AAA superfamily of proteins) depends primarily on its subcellular location. The microtubule-severing protein fidgetin (Fign) possesses a nuclear localization signal (NLS) that facilitates its translocation to the nucleus, where its assembly is finalized; here, Fign contributes to the regulation of microtubule configuration by cutting and trimming microtubule polymers. In the present study, Fign was found to be a nuclear protein, whose N-terminal sequence (SSLKRKAFYM; residues 314–323) acts as an NLS. Following substitution (KR to NN; 317–318) or deletion (NT; 314–323) mutations within the NLS, Fign, which is predominantly expressed in the nucleus, was found to reside in the cytoplasm of transfected cells. Furthermore, Fign was found to have an essential role in microtubule severing by preferentially targeting highly-tyrosinated microtubules (tyr-MTs). Mutation of the Fign NLS did not affect its microtubule-severing function or the cleavage of tyr-MTs, but did affect the cellular distribution of the Fign protein itself. Taken altogether, an NLS for Fign was identified, and it was demonstrated that the basic amino acids K317 and R318 are necessary for regulating its entry into the nucleus, whereas an increase in Fign in the cytosol due to mutations of the NLS did not affect its cleavage function.
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Affiliation(s)
- Jiong Li
- Department of Anatomy, Neuroscience Laboratory for Cognitive and Developmental Disorders, Medical College of Jinan University, Guangzhou, Guangdong 510632, P.R. China
| | - Fengming Wu
- Department of Anatomy, Neuroscience Laboratory for Cognitive and Developmental Disorders, Medical College of Jinan University, Guangzhou, Guangdong 510632, P.R. China
| | - Longfei Cheng
- Department of Anatomy, Neuroscience Laboratory for Cognitive and Developmental Disorders, Medical College of Jinan University, Guangzhou, Guangdong 510632, P.R. China
| | - Jiaqi Zhang
- Department of Anatomy, Neuroscience Laboratory for Cognitive and Developmental Disorders, Medical College of Jinan University, Guangzhou, Guangdong 510632, P.R. China
| | - Caihui Cha
- Department of Anatomy, Neuroscience Laboratory for Cognitive and Developmental Disorders, Medical College of Jinan University, Guangzhou, Guangdong 510632, P.R. China
| | - Li Chen
- Department of Anatomy, Neuroscience Laboratory for Cognitive and Developmental Disorders, Medical College of Jinan University, Guangzhou, Guangdong 510632, P.R. China
| | - Taoshan Feng
- Department of Anatomy, Neuroscience Laboratory for Cognitive and Developmental Disorders, Medical College of Jinan University, Guangzhou, Guangdong 510632, P.R. China
| | - Jifeng Zhang
- Department of Anatomy, Neuroscience Laboratory for Cognitive and Developmental Disorders, Medical College of Jinan University, Guangzhou, Guangdong 510632, P.R. China
| | - Guoqing Guo
- Department of Anatomy, Neuroscience Laboratory for Cognitive and Developmental Disorders, Medical College of Jinan University, Guangzhou, Guangdong 510632, P.R. China
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22
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RhoA-GTPase Modulates Neurite Outgrowth by Regulating the Expression of Spastin and p60-Katanin. Cells 2020; 9:cells9010230. [PMID: 31963385 PMCID: PMC7016723 DOI: 10.3390/cells9010230] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/10/2020] [Accepted: 01/14/2020] [Indexed: 12/17/2022] Open
Abstract
RhoA-GTPase (RhoA) is widely regarded as a key molecular switch to inhibit neurite outgrowth by rigidifying the actin cytoskeleton. However, during neurite outgrowth, whether and how microtubule dynamics are regulated by RhoA remains to be elucidated. Herein, CT04 and Y27632 were used to inactivate RhoA and its downstream effector Rho-associated coiled coil-forming kinase (ROCK), while the RhoAQ63L lentiviral vector was utilized to overexpress the constitutively activated RhoA in dorsal root ganglion (DRG) neurons or neuronal differentiated PC12 cells. The current data illustrate that the RhoA signaling pathway negatively modulates neurite outgrowth and elevates the expression of Glu-tubulin (a marker for a stabilized microtubule). Meanwhile, the microtubule-severing proteins spastin and p60-katanin were downregulated by the RhoA signaling pathway. When spastin and p60-katanin were knocked down, the effects of RhoA inhibition on neurite outgrowth were significantly reversed. Taken together, this study demonstrates that the RhoA pathway-mediated inhibition of neurite outgrowth is not only related to the modulation of microfilament dynamics but is also attributable to the regulation of the expression of spastin and p60-katanin and thus influences microtubule dynamics.
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23
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Hahn I, Voelzmann A, Liew YT, Costa-Gomes B, Prokop A. The model of local axon homeostasis - explaining the role and regulation of microtubule bundles in axon maintenance and pathology. Neural Dev 2019; 14:11. [PMID: 31706327 PMCID: PMC6842214 DOI: 10.1186/s13064-019-0134-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 10/02/2019] [Indexed: 12/20/2022] Open
Abstract
Axons are the slender, cable-like, up to meter-long projections of neurons that electrically wire our brains and bodies. In spite of their challenging morphology, they usually need to be maintained for an organism's lifetime. This makes them key lesion sites in pathological processes of ageing, injury and neurodegeneration. The morphology and physiology of axons crucially depends on the parallel bundles of microtubules (MTs), running all along to serve as their structural backbones and highways for life-sustaining cargo transport and organelle dynamics. Understanding how these bundles are formed and then maintained will provide important explanations for axon biology and pathology. Currently, much is known about MTs and the proteins that bind and regulate them, but very little about how these factors functionally integrate to regulate axon biology. As an attempt to bridge between molecular mechanisms and their cellular relevance, we explain here the model of local axon homeostasis, based on our own experiments in Drosophila and published data primarily from vertebrates/mammals as well as C. elegans. The model proposes that (1) the physical forces imposed by motor protein-driven transport and dynamics in the confined axonal space, are a life-sustaining necessity, but pose a strong bias for MT bundles to become disorganised. (2) To counterbalance this risk, MT-binding and -regulating proteins of different classes work together to maintain and protect MT bundles as necessary transport highways. Loss of balance between these two fundamental processes can explain the development of axonopathies, in particular those linking to MT-regulating proteins, motors and transport defects. With this perspective in mind, we hope that more researchers incorporate MTs into their work, thus enhancing our chances of deciphering the complex regulatory networks that underpin axon biology and pathology.
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Affiliation(s)
- Ines Hahn
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK
| | - André Voelzmann
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK
| | - Yu-Ting Liew
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK
| | - Beatriz Costa-Gomes
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK
| | - Andreas Prokop
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, The University of Manchester, School of Biology, Manchester, UK.
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24
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Kuo YW, Trottier O, Howard J. Predicted Effects of Severing Enzymes on the Length Distribution and Total Mass of Microtubules. Biophys J 2019; 117:2066-2078. [PMID: 31708162 DOI: 10.1016/j.bpj.2019.10.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/17/2019] [Accepted: 10/22/2019] [Indexed: 01/12/2023] Open
Abstract
Microtubules are dynamic cytoskeletal polymers whose growth and shrinkage are highly regulated as eukaryotic cells change shape, move, and divide. One family of microtubule regulators includes the ATP-hydrolyzing enzymes spastin, katanin, and fidgetin, which sever microtubule polymers into shorter fragments. Paradoxically, severases can increase microtubule number and mass in cells. Recent work with purified spastin and katanin accounts for this phenotype by showing that, in addition to severing, these enzymes modulate microtubule dynamics by accelerating the conversion of microtubules from their shrinking to their growing states and thereby promoting their regrowth. This leads to the observed exponential increase in microtubule mass. Spastin also influences the steady-state distribution of microtubule lengths, changing it from an exponential, as predicted by models of microtubule dynamic instability, to a peaked distribution. This effect of severing and regrowth by spastin on the microtubule length distribution has not been explained theoretically. To solve this problem, we formulated and solved a master equation for the time evolution of microtubule lengths in the presence of severing and microtubule dynamic instability. We then obtained numerical solutions to the steady-state length distribution and showed that the rate of severing and the speed of microtubule growth are the dominant parameters determining the steady-state length distribution. Furthermore, we found that the amplification rate is predicted to increase with severing, which is, to our knowledge, a new result. Our results establish a theoretical basis for how severing and dynamics together can serve to nucleate new microtubules, constituting a versatile mechanism to regulate microtubule length and mass.
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Affiliation(s)
- Yin-Wei Kuo
- Department of Chemistry, Yale University, New Haven, Connecticut; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut
| | - Olivier Trottier
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut; Department of Physics, Yale University, New Haven, Connecticut
| | - Jonathon Howard
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut.
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25
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Ansari A, Maffioletti E, Milanesi E, Marizzoni M, Frisoni GB, Blin O, Richardson JC, Bordet R, Forloni G, Gennarelli M, Bocchio-Chiavetto L. miR-146a and miR-181a are involved in the progression of mild cognitive impairment to Alzheimer's disease. Neurobiol Aging 2019; 82:102-109. [PMID: 31437718 DOI: 10.1016/j.neurobiolaging.2019.06.005] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 06/12/2019] [Accepted: 06/12/2019] [Indexed: 12/22/2022]
Abstract
The identification of mechanisms associated with Alzheimer's disease (AD) development in mild cognitive impairment (MCI) would be of great usefulness to clarify AD pathogenesis and to develop preventive and therapeutic strategies. In this study, blood levels of the candidate microRNAs (small noncoding RNAs that play a pivotal role in gene expression) miR-146a, miR-181a, miR-181b, miR-24-3p, miR-186a, miR-101, miR-339, miR-590, and miR-22 have been investigated for association to AD conversion within 2 years in a group of 45 patients with MCI. Baseline miR-146a (p = 0.036) and miR-181a (p = 0.026) showed a significant upregulation in patients with MCI who later converted to AD. These alterations were related to AD hallmarks: a significant negative correlation was found with amyloid beta cerebrospinal fluid concentration for miR-146a (p = 0.006) and miR-181a (p = 0.001). Moreover, higher levels of miR-146a were associated to apolipoprotein E ε4 allele presence, smaller volume of the hippocampus (p = 0.045) and of the CA1 (p = 0.013) and the subiculum (p = 0.027) subfields. Increased levels of miR-146a (p = 0.031) and miR-181a (p = 0.002) were also linked with diffusivity alterations in the cingulum. These data support a role for miR-146a and miR-181a in the mechanisms of AD progression.
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Affiliation(s)
- Abulaish Ansari
- Division of Biology and Genetics, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Elisabetta Maffioletti
- Division of Biology and Genetics, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Elena Milanesi
- Genetics Unit, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy; Department of Cellular and Molecular Medicine, 'Victor Babes' National Institute of Pathology, Bucharest, Romania
| | - Moira Marizzoni
- Laboratory of Neuroimaging and Alzheimer's Epidemiology, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy
| | - Giovanni B Frisoni
- Laboratory of Neuroimaging and Alzheimer's Epidemiology, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy; Memory Clinic and LANVIE - Laboratory of Neuroimaging of Aging, University Hospitals and University of Geneve, Geneve, Switzerland
| | - Oliver Blin
- AP-HM, CHU Timone, CIC CPCET, Service de Pharmacologie Clinique et Pharmacovigilance, Marseille, France
| | - Jill C Richardson
- Neurosciences Therapeutic Area Unit, GlaxoSmithKline R&D, Stevenage, UK; MRL UK, MSD, 2 Royal College Street, London, UK
| | - Regis Bordet
- U1171 Inserm, CHU Lille, Degenerative and Vascular Cognitive Disorders, University of Lille, Lille, France
| | - Gianluigi Forloni
- Neuroscience Department, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milano, Italy
| | - Massimo Gennarelli
- Division of Biology and Genetics, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy; Genetics Unit, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy.
| | - Luisella Bocchio-Chiavetto
- Genetics Unit, IRCCS Istituto Centro San Giovanni di Dio Fatebenefratelli, Brescia, Italy; Faculty of Psychology, eCampus University, Novedrate (Como), Italy
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26
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Baas PW, Qiang L. Tau: It's Not What You Think. Trends Cell Biol 2019; 29:452-461. [PMID: 30929793 PMCID: PMC6527491 DOI: 10.1016/j.tcb.2019.02.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 02/12/2019] [Accepted: 02/21/2019] [Indexed: 12/12/2022]
Abstract
Tau is a multifunctional microtubule-associated protein in the neuron. For decades, tau's main function in neurons has been broadly accepted as stabilizing microtubules in the axon; however, this conclusion was reached mainly on the basis of studies performed in vitro and on ectopic expression of tau in non-neuronal cells. The idea has become so prevailing that some disease researchers are even seeking to use microtubule-stabilizing drugs to treat diseases in which tau dissociates from microtubules. Recent work suggests that tau is not a stabilizer of microtubules in the axon, but rather enables axonal microtubules to have long labile domains, in part by outcompeting genuine stabilizers. This new perspective on tau challenges long-standing dogma.
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Affiliation(s)
- Peter W Baas
- Drexel University College of Medicine, Department of Neurobiology and Anatomy, 2900 Queen Lane, Philadelphia, PA 19129, USA.
| | - Liang Qiang
- Drexel University College of Medicine, Department of Neurobiology and Anatomy, 2900 Queen Lane, Philadelphia, PA 19129, USA
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27
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Knockdown of Fidgetin Improves Regeneration of Injured Axons by a Microtubule-Based Mechanism. J Neurosci 2019; 39:2011-2024. [PMID: 30647150 DOI: 10.1523/jneurosci.1888-18.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 11/21/2018] [Accepted: 12/24/2018] [Indexed: 12/16/2022] Open
Abstract
Fidgetin is a microtubule-severing protein that pares back the labile domains of microtubules in the axon. Experimental depletion of fidgetin results in elongation of the labile domains of microtubules and faster axonal growth. To test whether fidgetin knockdown assists axonal regeneration, we plated dissociated adult rat DRGs transduced using AAV5-shRNA-fidgetin on a laminin substrate with spots of aggrecan, a growth-inhibitory chondroitin sulfate proteoglycan. This cell culture assay mimics the glial scar formed after CNS injury. Aggrecan is more concentrated at the edge of the spot, such that axons growing from within the spot toward the edge encounter a concentration gradient that causes growth cones to become dystrophic and axons to retract or curve back on themselves. Fidgetin knockdown resulted in faster-growing axons on both laminin and aggrecan and enhanced crossing of axons from laminin onto aggrecan. Strikingly, axons from within the spot grew more avidly against the inhibitory aggrecan concentration gradient to cross onto laminin, without retracting or curving back. We also tested whether depleting fidgetin improves axonal regeneration in vivo after a dorsal root crush in adult female rats. Whereas control DRG neurons failed to extend axons across the dorsal root entry zone after injury, DRG neurons in which fidgetin was knocked down displayed enhanced regeneration of axons across the dorsal root entry zone into the spinal cord. Collectively, these results establish fidgetin as a novel therapeutic target to augment nerve regeneration and provide a workflow template by which microtubule-related targets can be compared in the future.SIGNIFICANCE STATEMENT Here we establish a workflow template from cell culture to animals in which microtubule-based treatments can be tested and compared with one another for their effectiveness in augmenting regeneration of injured axons relevant to spinal cord injury. The present work uses a viral transduction approach to knock down fidgetin from rat neurons, which coaxes nerve regeneration by elevating microtubule mass in their axons. Unlike previous strategies using microtubule-stabilizing drugs, fidgetin knockdown adds microtubule mass that is labile (rather than stable), thereby better recapitulating the growth status of a developing axon.
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28
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McNally FJ, Roll-Mecak A. Microtubule-severing enzymes: From cellular functions to molecular mechanism. J Cell Biol 2018; 217:4057-4069. [PMID: 30373906 PMCID: PMC6279391 DOI: 10.1083/jcb.201612104] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 08/13/2018] [Accepted: 10/04/2018] [Indexed: 12/24/2022] Open
Abstract
McNally and Roll-Mecak review the molecular mechanism of microtubule-severing enzymes and their diverse roles in processes ranging from cell division to ciliogensis and morphogenesis. Microtubule-severing enzymes generate internal breaks in microtubules. They are conserved in eukaryotes from ciliates to mammals, and their function is important in diverse cellular processes ranging from cilia biogenesis to cell division, phototropism, and neurogenesis. Their mutation leads to neurodegenerative and neurodevelopmental disorders in humans. All three known microtubule-severing enzymes, katanin, spastin, and fidgetin, are members of the meiotic subfamily of AAA ATPases that also includes VPS4, which disassembles ESCRTIII polymers. Despite their conservation and importance to cell physiology, the cellular and molecular mechanisms of action of microtubule-severing enzymes are not well understood. Here we review a subset of cellular processes that require microtubule-severing enzymes as well as recent advances in understanding their structure, biophysical mechanism, and regulation.
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Affiliation(s)
- Francis J McNally
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA
| | - Antonina Roll-Mecak
- Cell Biology and Biophysics Unit, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, Bethesda, MD .,Biochemistry and Biophysics Center, National Heart, Lung and Blood Institute, Bethesda, MD
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29
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Sudo H. Microtubule Hyperacetylation Enhances KL1-Dependent Micronucleation under a Tau Deficiency in Mammary Epithelial Cells. Int J Mol Sci 2018; 19:ijms19092488. [PMID: 30142893 PMCID: PMC6165458 DOI: 10.3390/ijms19092488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 08/19/2018] [Indexed: 12/20/2022] Open
Abstract
Enhanced microtubule acetylation has been identified as a negative prognostic indicator in breast cancer. We reported previously that primary cultured human mammary epithelial cells manifest breast cancer-related aneuploidization via the activation of severing protein katanin-like (KL)1 when tau is deficient. To address in this current study whether microtubule hyperacetylation is involved in breast carcinogenesis through mitosis, the effects of tubacin on human mammary epithelial cells were tested using immunofluorescence techniques. Tau-knockdown cells showed enhancement of KL1-dependent events, chromosome-bridging and micronucleation in response to tubacin. These enhancements were suppressed by further expression of an acetylation-deficient tubulin mutant. Consistently, using a rat fibroblast-based microtubule sensitivity test, it was confirmed that KL1 also shows enhanced activity in response to microtubule hyperacetylation as well as katanin. It was further observed in rat fibroblasts that exogenously expressed KL1 results in more micronucleation under microtubule hyperacetylation conditions. These data suggest that microtubule acetylation upregulates KL1 and induces more aneuploidy if tau is deficient. It is thus plausible that microtubule hyperacetylation promotes tumor progression by enhancing microtubule sensitivity to KL1, thereby disrupting spindle microtubules and this process could be reversed by the microtubule-binding and microtubule protective octapeptide NAPVSIPQ (NAP) which recruits tau to the microtubules.
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Affiliation(s)
- Haruka Sudo
- Faculty of Health Science, Tokoha University, 1-30, Mizuochi-cho, Aoi-ku, Shizuoka-shi, Shizuoka 420-0831, Japan.
- Department of Biochemistry, The Nippon Dental University School of Life Dentistry at Tokyo, 1-9-20 Fujimi, Chiyoda-ku, Tokyo 102-8159, Japan.
- Department of Anatomy, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
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Tau Does Not Stabilize Axonal Microtubules but Rather Enables Them to Have Long Labile Domains. Curr Biol 2018; 28:2181-2189.e4. [PMID: 30008334 DOI: 10.1016/j.cub.2018.05.045] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/16/2018] [Accepted: 05/16/2018] [Indexed: 11/22/2022]
Abstract
It is widely believed that tau stabilizes microtubules in the axon [1-3] and, hence, that disease-induced loss of tau from axonal microtubules leads to their destabilization [3-5]. An individual microtubule in the axon has a stable domain and a labile domain [6-8]. We found that tau is more abundant on the labile domain, which is inconsistent with tau's proposed role as a microtubule stabilizer. When tau is experimentally depleted from cultured rat neurons, the labile microtubule mass of the axon drops considerably, the remaining labile microtubule mass becomes less labile, and the stable microtubule mass increases. MAP6 (also called stable tubule-only polypeptide), which is normally enriched on the stable domain [9], acquires a broader distribution across the microtubule when tau is depleted, providing a potential explanation for the increase in stable microtubule mass. When MAP6 is depleted, the labile microtubule mass becomes even more labile, indicating that, unlike tau, MAP6 is a genuine stabilizer of axonal microtubules. We conclude that tau is not a stabilizer of axonal microtubules but is enriched on the labile domain of the microtubule to promote its assembly while limiting the binding to it of genuine stabilizers, such as MAP6. This enables the labile domain to achieve great lengths without being stabilized. These conclusions are contrary to tau dogma.
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31
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Lasser M, Tiber J, Lowery LA. The Role of the Microtubule Cytoskeleton in Neurodevelopmental Disorders. Front Cell Neurosci 2018; 12:165. [PMID: 29962938 PMCID: PMC6010848 DOI: 10.3389/fncel.2018.00165] [Citation(s) in RCA: 129] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 05/28/2018] [Indexed: 12/28/2022] Open
Abstract
Neurons depend on the highly dynamic microtubule (MT) cytoskeleton for many different processes during early embryonic development including cell division and migration, intracellular trafficking and signal transduction, as well as proper axon guidance and synapse formation. The coordination and support from MTs is crucial for newly formed neurons to migrate appropriately in order to establish neural connections. Once connections are made, MTs provide structural integrity and support to maintain neural connectivity throughout development. Abnormalities in neural migration and connectivity due to genetic mutations of MT-associated proteins can lead to detrimental developmental defects. Growing evidence suggests that these mutations are associated with many different neurodevelopmental disorders, including intellectual disabilities (ID) and autism spectrum disorders (ASD). In this review article, we highlight the crucial role of the MT cytoskeleton in the context of neurodevelopment and summarize genetic mutations of various MT related proteins that may underlie or contribute to neurodevelopmental disorders.
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Affiliation(s)
- Micaela Lasser
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Jessica Tiber
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Laura Anne Lowery
- Department of Biology, Boston College, Chestnut Hill, MA, United States
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32
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Fassier C, Fréal A, Gasmi L, Delphin C, Ten Martin D, De Gois S, Tambalo M, Bosc C, Mailly P, Revenu C, Peris L, Bolte S, Schneider-Maunoury S, Houart C, Nothias F, Larcher JC, Andrieux A, Hazan J. Motor axon navigation relies on Fidgetin-like 1-driven microtubule plus end dynamics. J Cell Biol 2018. [PMID: 29535193 PMCID: PMC5940295 DOI: 10.1083/jcb.201604108] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Fassier et al. identify Fidgetin-like 1 (Fignl1) as a key growth cone (GC)-enriched microtubule (MT)-associated protein in motor circuit wiring. They show that Fignl1 modulates motor GC morphology and steering behavior by down-regulating EB binding at MT plus ends and promoting MT depolymerization beneath the cell cortex. During neural circuit assembly, extrinsic signals are integrated into changes in growth cone (GC) cytoskeleton underlying axon guidance decisions. Microtubules (MTs) were shown to play an instructive role in GC steering. However, the numerous actors required for MT remodeling during axon navigation and their precise mode of action are far from being deciphered. Using loss- and gain-of-function analyses during zebrafish development, we identify in this study the meiotic clade adenosine triphosphatase Fidgetin-like 1 (Fignl1) as a key GC-enriched MT-interacting protein in motor circuit wiring and larval locomotion. We show that Fignl1 controls GC morphology and behavior at intermediate targets by regulating MT plus end dynamics and growth directionality. We further reveal that alternative translation of Fignl1 transcript is a sophisticated mechanism modulating MT dynamics: a full-length isoform regulates MT plus end–tracking protein binding at plus ends, whereas shorter isoforms promote their depolymerization beneath the cell cortex. Our study thus pinpoints Fignl1 as a multifaceted key player in MT remodeling underlying motor circuit connectivity.
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Affiliation(s)
- Coralie Fassier
- Sorbonne Universités, Université Pierre et Marie Curie-Université Paris 6, Institut de Biologie Paris-Seine, Unité de Neuroscience Paris Seine, Centre National de la Recherche Scientifique UMR 8246, Institut National de la Santé et de la Recherche Médicale U1130, Paris, France
| | - Amélie Fréal
- Sorbonne Universités, Université Pierre et Marie Curie-Université Paris 6, Institut de Biologie Paris-Seine, Unité de Neuroscience Paris Seine, Centre National de la Recherche Scientifique UMR 8246, Institut National de la Santé et de la Recherche Médicale U1130, Paris, France
| | - Laïla Gasmi
- Sorbonne Universités, Université Pierre et Marie Curie-Université Paris 6, Institut de Biologie Paris-Seine, Unité de Neuroscience Paris Seine, Centre National de la Recherche Scientifique UMR 8246, Institut National de la Santé et de la Recherche Médicale U1130, Paris, France
| | - Christian Delphin
- Institut National de la Santé et de la Recherche Médicale U1216, Université Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
| | - Daniel Ten Martin
- Sorbonne Universités, Université Pierre et Marie Curie-Université Paris 6, Institut de Biologie Paris-Seine, Unité de Neuroscience Paris Seine, Centre National de la Recherche Scientifique UMR 8246, Institut National de la Santé et de la Recherche Médicale U1130, Paris, France
| | - Stéphanie De Gois
- Sorbonne Universités, Université Pierre et Marie Curie-Université Paris 6, Institut de Biologie Paris-Seine, Unité de Neuroscience Paris Seine, Centre National de la Recherche Scientifique UMR 8246, Institut National de la Santé et de la Recherche Médicale U1130, Paris, France
| | - Monica Tambalo
- Sorbonne Universités, Université Pierre et Marie Curie-Université Paris 6, Institut de Biologie Paris-Seine, Unité de Neuroscience Paris Seine, Centre National de la Recherche Scientifique UMR 8246, Institut National de la Santé et de la Recherche Médicale U1130, Paris, France
| | - Christophe Bosc
- Institut National de la Santé et de la Recherche Médicale U1216, Université Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
| | - Philippe Mailly
- Centre for Interdisciplinary Research in Biology, Collège de France, Paris, France
| | - Céline Revenu
- Department of Genetics and Developmental Biology, Institut Curie, Paris, France
| | - Leticia Peris
- Institut National de la Santé et de la Recherche Médicale U1216, Université Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
| | - Susanne Bolte
- Sorbonne Universités, Université Pierre et Marie Curie-Université Paris 6, Institut de Biologie Paris-Seine, Centre National de la Recherche Scientifique FR3631, Paris, France
| | - Sylvie Schneider-Maunoury
- Sorbonne Universités, Université Pierre et Marie Curie-Université Paris 6, Institut de Biologie Paris-Seine, Biologie du Développement, Centre National de la Recherche Scientifique UMR7622, Paris, France
| | - Corinne Houart
- Medical Research Council Centre for Developmental Neurobiology, King's College London, Guy's Hospital Campus, London, England, UK
| | - Fatiha Nothias
- Sorbonne Universités, Université Pierre et Marie Curie-Université Paris 6, Institut de Biologie Paris-Seine, Unité de Neuroscience Paris Seine, Centre National de la Recherche Scientifique UMR 8246, Institut National de la Santé et de la Recherche Médicale U1130, Paris, France
| | - Jean-Christophe Larcher
- Sorbonne Universités, Université Pierre et Marie Curie-Université Paris 6, Institut de Biologie Paris-Seine, Biologie du Développement, Centre National de la Recherche Scientifique UMR7622, Paris, France
| | - Annie Andrieux
- Institut National de la Santé et de la Recherche Médicale U1216, Université Grenoble Alpes, Grenoble Institut Neurosciences, Grenoble, France
| | - Jamilé Hazan
- Sorbonne Universités, Université Pierre et Marie Curie-Université Paris 6, Institut de Biologie Paris-Seine, Unité de Neuroscience Paris Seine, Centre National de la Recherche Scientifique UMR 8246, Institut National de la Santé et de la Recherche Médicale U1130, Paris, France
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Wloga D, Joachimiak E, Fabczak H. Tubulin Post-Translational Modifications and Microtubule Dynamics. Int J Mol Sci 2017; 18:ijms18102207. [PMID: 29065455 PMCID: PMC5666887 DOI: 10.3390/ijms18102207] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/12/2017] [Accepted: 10/19/2017] [Indexed: 11/24/2022] Open
Abstract
Microtubules are hollow tube-like polymeric structures composed of α,β-tubulin heterodimers. They play an important role in numerous cellular processes, including intracellular transport, cell motility and segregation of the chromosomes during cell division. Moreover, microtubule doublets or triplets form a scaffold of a cilium, centriole and basal body, respectively. To perform such diverse functions microtubules have to differ in their properties. Post-translational modifications are one of the factors that affect the properties of the tubulin polymer. Here we focus on the direct and indirect effects of post-translational modifications of tubulin on microtubule dynamics.
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Affiliation(s)
- Dorota Wloga
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093 Warsaw, Poland.
| | - Ewa Joachimiak
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093 Warsaw, Poland.
| | - Hanna Fabczak
- Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str., 02-093 Warsaw, Poland.
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34
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Leo L, Weissmann C, Burns M, Kang M, Song Y, Qiang L, Brady ST, Baas PW, Morfini G. Mutant spastin proteins promote deficits in axonal transport through an isoform-specific mechanism involving casein kinase 2 activation. Hum Mol Genet 2017; 26:2321-2334. [PMID: 28398512 DOI: 10.1093/hmg/ddx125] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 03/24/2017] [Indexed: 01/19/2023] Open
Abstract
Mutations of various genes cause hereditary spastic paraplegia (HSP), a neurological disease involving dying-back degeneration of upper motor neurons. From these, mutations in the SPAST gene encoding the microtubule-severing protein spastin account for most HSP cases. Cumulative genetic and experimental evidence suggests that alterations in various intracellular trafficking events, including fast axonal transport (FAT), may contribute to HSP pathogenesis. However, the mechanisms linking SPAST mutations to such deficits remain largely unknown. Experiments presented here using isolated squid axoplasm reveal inhibition of FAT as a common toxic effect elicited by spastin proteins with different HSP mutations, independent of microtubule-binding or severing activity. Mutant spastin proteins produce this toxic effect only when presented as the tissue-specific M1 isoform, not when presented as the ubiquitously-expressed shorter M87 isoform. Biochemical and pharmacological experiments further indicate that the toxic effects of mutant M1 spastins on FAT involve casein kinase 2 (CK2) activation. In mammalian cells, expression of mutant M1 spastins, but not their mutant M87 counterparts, promotes abnormalities in the distribution of intracellular organelles that are correctable by pharmacological CK2 inhibition. Collectively, these results demonstrate isoform-specific toxic effects of mutant M1 spastin on FAT, and identify CK2 as a critical mediator of these effects.
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Affiliation(s)
- Lanfranco Leo
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Carina Weissmann
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Matthew Burns
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA
| | - Minsu Kang
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA.,Marine Biological Laboratory, Woods Hole, MA, USA
| | - Yuyu Song
- Marine Biological Laboratory, Woods Hole, MA, USA.,Department of Genetics, School of Medicine, Yale University, New Haven, CT, USA
| | - Liang Qiang
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Scott T Brady
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA.,Marine Biological Laboratory, Woods Hole, MA, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Gerardo Morfini
- Department of Anatomy and Cell Biology, University of Illinois at Chicago, Chicago, IL, USA.,Marine Biological Laboratory, Woods Hole, MA, USA
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35
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Qu X, Yuan FN, Corona C, Pasini S, Pero ME, Gundersen GG, Shelanski ML, Bartolini F. Stabilization of dynamic microtubules by mDia1 drives Tau-dependent Aβ 1-42 synaptotoxicity. J Cell Biol 2017; 216:3161-3178. [PMID: 28877993 PMCID: PMC5626542 DOI: 10.1083/jcb.201701045] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 06/15/2017] [Accepted: 07/26/2017] [Indexed: 01/17/2023] Open
Abstract
Oligomeric Amyloid β1-42 (Aβ) plays a crucial synaptotoxic role in Alzheimer's disease, and hyperphosphorylated tau facilitates Aβ toxicity. The link between Aβ and tau, however, remains controversial. In this study, we find that in hippocampal neurons, Aβ acutely induces tubulin posttranslational modifications (PTMs) and stabilizes dynamic microtubules (MTs) by reducing their catastrophe frequency. Silencing or acute inhibition of the formin mDia1 suppresses these activities and corrects the synaptotoxicity and deficits of axonal transport induced by Aβ. We explored the mechanism of rescue and found that stabilization of dynamic MTs promotes tau-dependent loss of dendritic spines and tau hyperphosphorylation. Collectively, these results uncover a novel role for mDia1 in Aβ-mediated synaptotoxicity and demonstrate that inhibition of MT dynamics and accumulation of PTMs are driving factors for the induction of tau-mediated neuronal damage.
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Affiliation(s)
- Xiaoyi Qu
- Department of Pathology, Anatomy and Cell Biology, Columbia University, New York, NY
| | - Feng Ning Yuan
- Department of Pathology, Anatomy and Cell Biology, Columbia University, New York, NY
| | - Carlo Corona
- Department of Pathology, Anatomy and Cell Biology, Columbia University, New York, NY
| | - Silvia Pasini
- Department of Pathology, Anatomy and Cell Biology, Columbia University, New York, NY
| | - Maria Elena Pero
- Department of Pathology, Anatomy and Cell Biology, Columbia University, New York, NY.,Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - Gregg G Gundersen
- Department of Pathology, Anatomy and Cell Biology, Columbia University, New York, NY
| | - Michael L Shelanski
- Department of Pathology, Anatomy and Cell Biology, Columbia University, New York, NY
| | - Francesca Bartolini
- Department of Pathology, Anatomy and Cell Biology, Columbia University, New York, NY
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36
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Austin TO, Matamoros AJ, Friedman JM, Friedman AJ, Nacharaju P, Yu W, Sharp DJ, Baas PW. Nanoparticle Delivery of Fidgetin siRNA as a Microtubule-based Therapy to Augment Nerve Regeneration. Sci Rep 2017; 7:9675. [PMID: 28852085 PMCID: PMC5575010 DOI: 10.1038/s41598-017-10250-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/04/2017] [Indexed: 12/28/2022] Open
Abstract
Microtubule-stabilizing drugs have gained popularity for treating injured adult axons, the rationale being that increased stabilization of microtubules will prevent the axon from retracting and fortify it to grow through inhibitory molecules associated with nerve injury. We have posited that a better approach would be not to stabilize the microtubules, but to increase labile microtubule mass to levels more conducive to axonal growth. Recent work on fetal neurons suggests this can be accomplished using RNA interference to reduce the levels of fidgetin, a microtubule-severing protein. Methods to introduce RNA interference into adult neurons, in vitro or in vivo, have been problematic and not translatable to human patients. Here we show that a novel nanoparticle approach, previously shown to deliver siRNA into tissues and organs, enables siRNA to gain entry into adult rat dorsal root ganglion neurons in culture. Knockdown of fidgetin is partial with this approach, but sufficient to increase the labile microtubule mass of the axon, thereby increasing axonal growth. The increase in axonal growth occurs on both a favorable substrate and a growth-inhibitory molecule associated with scar formation in injured spinal cord. The nanoparticles are readily translatable to in vivo studies on animals and ultimately to clinical applications.
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Affiliation(s)
- Timothy O Austin
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - Andrew J Matamoros
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - Joel M Friedman
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Adam J Friedman
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.,Department of Dermatology, George Washington School of Medicine and Health Sciences, Washington, DC, 20037, USA
| | - Parimala Nacharaju
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Wenqian Yu
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - David J Sharp
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA.
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37
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Bailey ME, Jiang N, Dima RI, Ross JL. Invited review: Microtubule severing enzymes couple atpase activity with tubulin GTPase spring loading. Biopolymers 2017; 105:547-56. [PMID: 27037673 DOI: 10.1002/bip.22842] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 03/23/2016] [Accepted: 03/28/2016] [Indexed: 12/21/2022]
Abstract
Microtubules are amazing filaments made of GTPase enzymes that store energy used for their own self-destruction to cause a stochastically driven dynamics called dynamic instability. Dynamic instability can be reproduced in vitro with purified tubulin, but the dynamics do not mimic that observed in cells. This is because stabilizers and destabilizers act to alter microtubule dynamics. One interesting and understudied class of destabilizers consists of the microtubule-severing enzymes from the ATPases Associated with various cellular Activities (AAA+) family of ATP-enzymes. Here we review current knowledge about GTP-driven microtubule dynamics and how that couples to ATP-driven destabilization by severing enzymes. We present a list of challenges regarding the mechanism of severing, which require development of experimental and modeling approaches to shed light as to how severing enzymes can act to regulate microtubule dynamics in cells. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 547-556, 2016.
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Affiliation(s)
- Megan E Bailey
- Department of Physiology and Biophysics, 1705 NE Pacific St., Seattle, WA 98195
| | - Nan Jiang
- Department of Chemistry, University of Cincinnati, Cincinnati OH 45221
| | - Ruxandra I Dima
- Department of Chemistry, University of Cincinnati, Cincinnati OH 45221
| | - Jennifer L Ross
- Department of Physics, 666 N. Pleasant St. University of Massachusetts, Amherst, MA 01003
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38
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Brunden KR, Lee VMY, Smith AB, Trojanowski JQ, Ballatore C. Altered microtubule dynamics in neurodegenerative disease: Therapeutic potential of microtubule-stabilizing drugs. Neurobiol Dis 2016; 105:328-335. [PMID: 28012891 DOI: 10.1016/j.nbd.2016.12.021] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/12/2016] [Accepted: 12/21/2016] [Indexed: 02/04/2023] Open
Abstract
Many neurodegenerative diseases are characterized by deficiencies in neuronal axonal transport, a process in which cellular cargo is shuttled with the aid of molecular motors from the cell body to axonal termini and back along microtubules (MTs). Proper axonal transport is critical to the normal functioning of neurons, and impairments in this process could contribute to the neuronal damage and death that is characteristic of neurodegenerative disease. Although the causes of axonal transport abnormalities may vary among the various neurodegenerative conditions, in many cases it appears that the transport deficiencies result from a diminution of axonal MT stability. Here we review the evidence of MT abnormalities in a number of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and traumatic brain injury, and highlight the potential benefit of MT-stabilizing agents in improving axonal transport and nerve function in these diseases. Moreover, we discuss the challenges associated with the utilization of MT-stabilizing drugs as therapeutic candidates for neurodegenerative conditions.
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Affiliation(s)
- Kurt R Brunden
- Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States.
| | - Virginia M-Y Lee
- Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Amos B Smith
- Department of Chemistry, School of Arts and Science, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - John Q Trojanowski
- Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Carlo Ballatore
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, United States
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39
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Hu Z, Feng J, Bo W, Wu R, Dong Z, Liu Y, Qiang L, Liu M. Fidgetin regulates cultured astrocyte migration by severing tyrosinated microtubules at the leading edge. Mol Biol Cell 2016; 28:545-553. [PMID: 27974640 PMCID: PMC5305261 DOI: 10.1091/mbc.e16-09-0628] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 12/02/2022] Open
Abstract
Fign regulates cultured astrocyte migration by severing tyrosinated microtubules (MTs). Inhibition of cellular migration induced by Fign knockdown can be rescued with concomitant knockdown of kinesin-12. A working model is given for the MT reconfiguration underlying cellular migration elicited by the cooperation of two distinct MT-related proteins. Microtubule (MT) organization is essential for many cellular events, including mitosis, migration, and cell polarity. Fidgetin (Fign), an ATP-dependent, MT-severing protein, contributes to the regulation of MT configuration by cutting and trimming MT polymers. Functions of Fign have been indicated in neurite outgrowth, mitosis, meiosis, and cellular migration. Here we focus on migration of astrocytes. We find that Fign plays an essential role in cultured astrocyte migration by preferentially targeting MTs (or regions of MTs) that are rich in tyrosinated tubulin, a marker for especially dynamic MTs or especially dynamic regions of MTs. Inhibition of cellular migration induced by Fign knockdown can be rescued with concomitant knockdown of kinesin-12, a motor protein best known for its role in mitosis. We propose a novel working model for MT reconfiguration underlying cellular migration elicited by the functional cooperation of two distinct MT-related proteins.
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Affiliation(s)
- Zunlu Hu
- Key Laboratory of Neuroregeneration, Jiangsu, and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Jie Feng
- Key Laboratory of Neuroregeneration, Jiangsu, and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Weijuan Bo
- Key Laboratory of Neuroregeneration, Jiangsu, and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Ronghua Wu
- Key Laboratory of Neuroregeneration, Jiangsu, and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Zhangji Dong
- Key Laboratory of Neuroregeneration, Jiangsu, and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Yan Liu
- Key Laboratory of Neuroregeneration, Jiangsu, and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Liang Qiang
- Key Laboratory of Neuroregeneration, Jiangsu, and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China .,Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129
| | - Mei Liu
- Key Laboratory of Neuroregeneration, Jiangsu, and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
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40
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Baas PW, Rao AN, Matamoros AJ, Leo L. Stability properties of neuronal microtubules. Cytoskeleton (Hoboken) 2016; 73:442-60. [PMID: 26887570 PMCID: PMC5541393 DOI: 10.1002/cm.21286] [Citation(s) in RCA: 184] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/02/2016] [Accepted: 02/12/2016] [Indexed: 01/12/2023]
Abstract
Neurons are terminally differentiated cells that use their microtubule arrays not for cell division but rather as architectural elements required for the elaboration of elongated axons and dendrites. In addition to acting as compression-bearing struts that provide for the shape of the neuron, microtubules also act as directional railways for organelle transport. The stability properties of neuronal microtubules are commonly discussed in the biomedical literature as crucial to the development and maintenance of the nervous system, and have recently gained attention as central to the etiology of neurodegenerative diseases. Drugs that affect microtubule stability are currently under investigation as potential therapies for disease and injury of the nervous system. There is often a lack of consistency, however, in how the issue of microtubule stability is discussed in the literature, and this can affect the design and interpretation of experiments as well as potential therapeutic regimens. Neuronal microtubules are considered to be more stable than microtubules in dividing cells. On average, this is true, but in addition to an abundant stable microtubule fraction in neurons, there is also an abundant labile microtubule fraction. Both are functionally important. Individual microtubules consist of domains that differ in their stability properties, and these domains can also differ markedly in their composition as well as how they interact with various microtubule-related proteins in the neuron. Myriad proteins and pathways have been discussed as potential contributors to microtubule stability in neurons. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA.
| | - Anand N Rao
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Andrew J Matamoros
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Lanfranco Leo
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
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41
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van Beuningen SFB, Hoogenraad CC. Neuronal polarity: remodeling microtubule organization. Curr Opin Neurobiol 2016; 39:1-7. [DOI: 10.1016/j.conb.2016.02.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 02/12/2016] [Indexed: 01/16/2023]
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42
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Zhao X, Jin M, Wang M, Sun L, Hong X, Cao Y, Wang C. Fidgetin-like 1 is a ciliogenesis-inhibitory centrosome protein. Cell Cycle 2016; 15:2367-75. [PMID: 27384458 DOI: 10.1080/15384101.2016.1204059] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Fidgetin-like 1 (FIGL-1) is a homolog of fidgetin, an AAA protein that was identified as the protein encoded by the gene mutated in fidget mice. Because the phenotypes of fidget mice are reminiscent of the phenotypes of ciliopathy diseases, and because fidgetin has microtubule-severing activity, we hypothesize that these proteins participate in cilia-related processes. Indeed, overexpression of FIGL-1 interfered with ciliogenesis in cultured cells. In particular, overexpressed FIGL-1 strongly accumulated at the centrosome, and, when highly expressed, perturbed the localization of centrosomal proteins such as pericentrin, CP110, and centrin. Using a polyclonal antibody against human FIGL-1, we found that endogenous FIGL-1 localized preferentially around the mother centriole. Consistently, depletion of FIGL-1 by shRNA treatment enhanced ciliogenesis in HEK293T cells. By checking the integrity of the cytoplasmic microtubule network in FIGL-1-overexpressing cells, we found that FIGL-1 probably has microtubule-severing activity, as suggested by its sequence homology with other microtubule-severing proteins. Furthermore, we showed that overexpression of FIGL-1 in zebrafish embryo decreased the length of cilia and perturbed the heart laterality. Taken together, these results demonstrate that FIGL-1 is a new centrosomal protein and inhibits ciliogenesis. These results extend the already long list of centrosomal proteins and provide new insights into the regulation of ciliogenesis.
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Affiliation(s)
- Xiaoyu Zhao
- a Department of Central Laboratory , Shanghai 10th People's Hospital, School of Life Sciences and Technology, Tongji University , Shanghai , China
| | - Miaomiao Jin
- a Department of Central Laboratory , Shanghai 10th People's Hospital, School of Life Sciences and Technology, Tongji University , Shanghai , China
| | - Mengzhu Wang
- a Department of Central Laboratory , Shanghai 10th People's Hospital, School of Life Sciences and Technology, Tongji University , Shanghai , China
| | - Lili Sun
- a Department of Central Laboratory , Shanghai 10th People's Hospital, School of Life Sciences and Technology, Tongji University , Shanghai , China
| | - Xuejiao Hong
- a Department of Central Laboratory , Shanghai 10th People's Hospital, School of Life Sciences and Technology, Tongji University , Shanghai , China
| | - Ying Cao
- a Department of Central Laboratory , Shanghai 10th People's Hospital, School of Life Sciences and Technology, Tongji University , Shanghai , China
| | - Chunguang Wang
- a Department of Central Laboratory , Shanghai 10th People's Hospital, School of Life Sciences and Technology, Tongji University , Shanghai , China
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43
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Microtubules in health and degenerative disease of the nervous system. Brain Res Bull 2016; 126:217-225. [PMID: 27365230 DOI: 10.1016/j.brainresbull.2016.06.016] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/22/2016] [Accepted: 06/27/2016] [Indexed: 01/04/2023]
Abstract
Microtubules are essential for the development and maintenance of axons and dendrites throughout the life of the neuron, and are vulnerable to degradation and disorganization in a variety of neurodegenerative diseases. Microtubules, polymers of tubulin heterodimers, are intrinsically polar structures with a plus end favored for assembly and disassembly and a minus end less favored for these dynamics. In the axon, microtubules are nearly uniformly oriented with plus ends out, whereas in dendrites, microtubules have mixed orientations. Microtubules in developing neurons typically have a stable domain toward the minus end and a labile domain toward the plus end. This domain structure becomes more complex during neuronal maturation when especially stable patches of polyaminated tubulin become more prominent within the microtubule. Microtubules are the substrates for molecular motor proteins that transport cargoes toward the plus or minus end of the microtubule, with motor-driven forces also responsible for organizing microtubules into their distinctive polarity patterns in axons and dendrites. A vast array of microtubule-regulatory proteins impart direct and indirect changes upon the microtubule arrays of the neuron, and these include microtubule-severing proteins as well as proteins responsible for the stability properties of the microtubules. During neurodegenerative diseases, microtubule mass is commonly diminished, and the potential exists for corruption of the microtubule polarity patterns and microtubule-mediated transport. These ill effects may be a primary causative factor in the disease or may be secondary effects, but regardless, therapeutics capable of correcting these microtubule abnormalities have great potential to improve the status of the degenerating nervous system.
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44
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Kahn OI, Baas PW. Microtubules and Growth Cones: Motors Drive the Turn. Trends Neurosci 2016; 39:433-440. [PMID: 27233682 DOI: 10.1016/j.tins.2016.04.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 04/19/2016] [Accepted: 04/21/2016] [Indexed: 01/09/2023]
Abstract
Navigation of the growth cone at the tip of the developing axon is crucial for the proper wiring of the nervous system. Mechanisms of actin-dependent growth cone steering, via signaling cascades, are well documented. Microtubules are also important in growth cone guidance, because their polarized invasion into the peripheral domain on one side of the growth cone is essential for it to turn in that direction. Classically, microtubules have been considered secondary players, invading the peripheral domain only where the actin cytoskeleton permits them to go. Presented here is evidence for an underappreciated mechanism by which signaling cascades can potentially affect growth cone turning, namely through regulatable forces imposed on the microtubules by molecular motor proteins.
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Affiliation(s)
- Olga I Kahn
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA
| | - Peter W Baas
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, USA.
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45
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Abstract
Dendrite branching is an essential process for building complex nervous systems. It determines the number, distribution and integration of inputs into a neuron, and is regulated to create the diverse dendrite arbor branching patterns characteristic of different neuron types. The microtubule cytoskeleton is critical to provide structure and exert force during dendrite branching. It also supports the functional requirements of dendrites, reflected by differential microtubule architectural organization between neuron types, illustrated here for sensory neurons. Both anterograde and retrograde microtubule polymerization occur within growing dendrites, and recent studies indicate that branching is enhanced by anterograde microtubule polymerization events in nascent branches. The polarities of microtubule polymerization events are regulated by the position and orientation of microtubule nucleation events in the dendrite arbor. Golgi outposts are a primary microtubule nucleation center in dendrites and share common nucleation machinery with the centrosome. In addition, pre-existing dendrite microtubules may act as nucleation sites. We discuss how balancing the activities of distinct nucleation machineries within the growing dendrite can alter microtubule polymerization polarity and dendrite branching, and how regulating this balance can generate neuron type-specific morphologies.
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Affiliation(s)
- Caroline Delandre
- a Laboratory for Genetic Control of Neuronal Architecture, RIKEN Brain Science Institute , Wako , Saitama , Japan
| | - Reiko Amikura
- a Laboratory for Genetic Control of Neuronal Architecture, RIKEN Brain Science Institute , Wako , Saitama , Japan
| | - Adrian W Moore
- a Laboratory for Genetic Control of Neuronal Architecture, RIKEN Brain Science Institute , Wako , Saitama , Japan
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46
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Zempel H, Mandelkow EM. Tau missorting and spastin-induced microtubule disruption in neurodegeneration: Alzheimer Disease and Hereditary Spastic Paraplegia. Mol Neurodegener 2015; 10:68. [PMID: 26691836 PMCID: PMC4687341 DOI: 10.1186/s13024-015-0064-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 12/08/2015] [Indexed: 12/16/2022] Open
Abstract
In Alzheimer Disease (AD), the mechanistic connection of the two major pathological hallmarks, namely deposition of Amyloid-beta (Aβ) in the form of extracellular plaques, and the pathological changes of the intracellular protein Tau (such as phosphorylation, missorting, aggregation), is not well understood. Genetic evidence from AD and Down Syndrome (Trisomy 21), and animal models thereof, suggests that aberrant production of Aβ is upstream of Tau aggregation, but also points to Tau as a critical effector in the pathological process. Yet, the cascade of events leading from increased levels of Aβ to Tau-dependent toxicity remains a matter of debate. Using primary neurons exposed to oligomeric forms of Aβ, we have found that Tau becomes mislocalized (missorted) into the somatodendritic compartment. Missorting of Tau correlates with loss of microtubules and downstream consequences such as loss of mature spines, loss of synaptic activity, and mislocalization of mitochondria. In this cascade, missorting of Tau induces mislocalization of TTLL6 (Tubulin-Tyrosine-Ligase-Like 6) into the dendrites. TTLL6 induces polyglutamylation of microtubules, which acts as a trigger for spastin mediated severing of dendritic microtubules. Loss of microtubules makes cells unable to maintain transport of mitochondria, which in turn results in synaptic dysfunction and loss of mature spines. These pathological changes are absent in TauKO derived primary neurons. Thus, Tau mediated mislocalization of TTLL6 and spastin activation reveals a pathological gain of function for Tau and spastin in this cellular model system of AD. In contrast, in hereditary spastic paraplegia (HSP) caused by mutations of the gene encoding spastin (spg4 alias SPAST), spastin function in terms of microtubule severing is decreased at least for the gene product of the mutated allele, resulting in overstable microtubules in disease model systems. Whether total spastin severing activity or microtubule stability in human disease is also affected is not yet clear. No human disease has been associated so far with the long-chain polyglutamylation enzyme TTLL6, or the other TTLLs (1,5,11) possibly involved. Here we review the findings supporting a role for Tau, spastin and TTLL6 in AD and other tauopathies, HSP and neurodegeneration, and summarize possible therapeutic approaches for AD and HSP.
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Affiliation(s)
- Hans Zempel
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany. .,MPI for Metabolism Research, Hamburg Outstation, c/o DESY, Hamburg, Germany.
| | - Eva-Maria Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany. .,CAESAR Research Center, Bonn, Germany. .,MPI for Metabolism Research, Hamburg Outstation, c/o DESY, Hamburg, Germany.
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