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Kotaich F, Caillol D, Bomont P. Neurofilaments in health and Charcot-Marie-Tooth disease. Front Cell Dev Biol 2023; 11:1275155. [PMID: 38164457 PMCID: PMC10758125 DOI: 10.3389/fcell.2023.1275155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 10/02/2023] [Indexed: 01/03/2024] Open
Abstract
Neurofilaments (NFs) are the most abundant component of mature neurons, that interconnect with actin and microtubules to form the cytoskeleton. Specifically expressed in the nervous system, NFs present the particularity within the Intermediate Filament family of being formed by four subunits, the neurofilament light (NF-L), medium (NF-M), heavy (NF-H) proteins and α-internexin or peripherin. Here, we review the current knowledge on NF proteins and neurofilaments, from their domain structures and their model of assembly to the dynamics of their transport and degradation along the axon. The formation of the filament and its behaviour are regulated by various determinants, including post-transcriptional (miRNA and RBP proteins) and post-translational (phosphorylation and ubiquitination) modifiers. Altogether, the complex set of modifications enable the neuron to establish a stable but elastic NF array constituting the structural scaffold of the axon, while permitting the local expression of NF proteins and providing the dynamics necessary to fulfil local demands and respond to stimuli and injury. Thus, in addition to their roles in mechano-resistance, radial axonal outgrowth and nerve conduction, NFs control microtubule dynamics, organelle distribution and neurotransmission at the synapse. We discuss how the studies of neurodegenerative diseases with NF aggregation shed light on the biology of NFs. In particular, the NEFL and NEFH genes are mutated in Charcot-Marie-Tooth (CMT) disease, the most common inherited neurological disorder of the peripheral nervous system. The clinical features of the CMT forms (axonal CMT2E, CMT2CC; demyelinating CMT1F; intermediate I-CMT) with symptoms affecting the central nervous system (CNS) will allow us to further investigate the physiological roles of NFs in the brain. Thus, NF-CMT mouse models exhibit various degrees of sensory-motor deficits associated with CNS symptoms. Cellular systems brought findings regarding the dominant effect of NF-L mutants on NF aggregation and transport, although these have been recently challenged. Neurofilament detection without NF-L in recessive CMT is puzzling, calling for a re-examination of the current model in which NF-L is indispensable for NF assembly. Overall, we discuss how the fundamental and translational fields are feeding each-other to increase but also challenge our knowledge of NF biology, and to develop therapeutic avenues for CMT and neurodegenerative diseases with NF aggregation.
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Affiliation(s)
| | | | - Pascale Bomont
- ERC team, NeuroMyoGene Institute-Pathophysiology and Genetics of Neuron and Muscle, Inserm U1315, CNRS UMR5261, University of Lyon 1, Lyon, France
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2
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Doganyigit Z, Eroglu E, Okan A. Intermediate filament proteins are reliable immunohistological biomarkers to help diagnose multiple tissue-specific diseases. Anat Histol Embryol 2023; 52:655-672. [PMID: 37329162 DOI: 10.1111/ahe.12937] [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: 11/27/2022] [Revised: 05/18/2023] [Accepted: 05/31/2023] [Indexed: 06/18/2023]
Abstract
Cytoskeletal networks are proteins that effectively maintain cell integrity and provide mechanical support to cells by actively transmitting mechanical signals. Intermediate filaments, which are from the cytoskeleton family and are 10 nanometres in diameter, are unlike actin and microtubules, which are highly dynamic cytoskeletal elements. Intermediate filaments are flexible at low strain, harden at high strain and resist breaking. For this reason, these filaments fulfil structural functions by providing mechanical support to the cells through their different strain-hardening properties. Intermediate filaments are suitable in that cells both cope with mechanical forces and modulate signal transmission. These filaments are composed of fibrous proteins that exhibit a central α-helical rod domain with a conserved substructure. Intermediate filament proteins are divided into six groups. Type I and type II include acidic and basic keratins, type III, vimentin, desmin, peripheralin and glial fibrillary acidic protein (GFAP), respectively. Type IV intermediate filament group includes neurofilament proteins and a fourth neurofilament subunit, α-internexin proteins. Type V consists of lamins located in the nucleus, and the type VI group consists of lens-specific intermediate filaments, CP49/phakinin and filen. Intermediate filament proteins show specific immunoreactivity in differentiating cells and mature cells of various types. Various carcinomas such as colorectal, urothelial and ovarian, diseases such as chronic pancreatitis, cirrhosis, hepatitis and cataract have been associated with intermediate filaments. Accordingly, this section reviews available immunohistochemical antibodies to intermediate filament proteins. Identification of intermediate filament proteins by methodological methods may contribute to the understanding of complex diseases.
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Affiliation(s)
- Zuleyha Doganyigit
- Faculty of Medicine, Histology and Embryology, Yozgat Bozok University, Yozgat, Turkey
| | - Ece Eroglu
- Faculty of Medicine, Yozgat Bozok University, Yozgat, Turkey
| | - Aslı Okan
- Faculty of Medicine, Histology and Embryology, Yozgat Bozok University, Yozgat, Turkey
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3
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Lefebvre-Omar C, Liu E, Dalle C, d'Incamps BL, Bigou S, Daube C, Karpf L, Davenne M, Robil N, Jost Mousseau C, Blanchard S, Tournaire G, Nicaise C, Salachas F, Lacomblez L, Seilhean D, Lobsiger CS, Millecamps S, Boillée S, Bohl D. Neurofilament accumulations in amyotrophic lateral sclerosis patients' motor neurons impair axonal initial segment integrity. Cell Mol Life Sci 2023; 80:150. [PMID: 37184603 DOI: 10.1007/s00018-023-04797-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 04/24/2023] [Accepted: 05/03/2023] [Indexed: 05/16/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is the most common motor neuron (MN) disease in adults with no curative treatment. Neurofilament (NF) level in patient' fluids have recently emerged as the prime biomarker of ALS disease progression, while NF accumulation in MNs of patients is the oldest and one of the best pathological hallmarks. However, the way NF accumulations could lead to MN degeneration remains unknown. To assess NF accumulations and study the impact on MNs, we compared MNs derived from induced pluripotent stem cells (iPSC) of patients carrying mutations in C9orf72, SOD1 and TARDBP genes, the three main ALS genetic causes. We show that in all mutant MNs, light NF (NF-L) chains rapidly accumulate in MN soma, while the phosphorylated heavy/medium NF (pNF-M/H) chains pile up in axonal proximal regions of only C9orf72 and SOD1 MNs. Excitability abnormalities were also only observed in these latter MNs. We demonstrate that the integrity of the MN axonal initial segment (AIS), the region of action potential initiation and responsible for maintaining axonal integrity, is impaired in the presence of pNF-M/H accumulations in C9orf72 and SOD1 MNs. We establish a strong correlation between these pNF-M/H accumulations, an AIS distal shift, increased axonal calibers and modified repartition of sodium channels. The results expand our understanding of how NF accumulation could dysregulate components of the axonal cytoskeleton and disrupt MN homeostasis. With recent cumulative evidence that AIS alterations are implicated in different brain diseases, preserving AIS integrity could have important therapeutic implications for ALS.
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Affiliation(s)
- Cynthia Lefebvre-Omar
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Elise Liu
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Carine Dalle
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Boris Lamotte d'Incamps
- Université Paris-Cité, CNRS, Saints-Pères Paris Institute for the Neurosciences, Paris, France
| | - Stéphanie Bigou
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Clément Daube
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Léa Karpf
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Marc Davenne
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | | | - Coline Jost Mousseau
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Stéphane Blanchard
- Institut Pasteur, INSERM U1115, Unité Biothérapies pour les Maladies Neurodégénératives, Paris, France
| | - Guillaume Tournaire
- Institut Pasteur, INSERM U1115, Unité Biothérapies pour les Maladies Neurodégénératives, Paris, France
| | | | - François Salachas
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
- Département de Neurologie, Assistance Publique Hôpitaux de Paris (APHP), Centre de Référence SLA Ile de France, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Lucette Lacomblez
- Département de Neurologie, Assistance Publique Hôpitaux de Paris (APHP), Centre de Référence SLA Ile de France, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Danielle Seilhean
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
- Département de Neuropathologie, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Christian S Lobsiger
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Stéphanie Millecamps
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Séverine Boillée
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Delphine Bohl
- Sorbonne Université, Institut du Cerveau-Paris Brain Institute-ICM, Inserm, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France.
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4
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Rao MV, Darji S, Stavrides PH, Goulbourne CN, Kumar A, Yang DS, Yoo L, Peddy J, Lee JH, Yuan A, Nixon RA. Autophagy is a novel pathway for neurofilament protein degradation in vivo. Autophagy 2023; 19:1277-1292. [PMID: 36131358 PMCID: PMC10012948 DOI: 10.1080/15548627.2022.2124500] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
How macroautophagy/autophagy influences neurofilament (NF) proteins in neurons, a frequent target in neurodegenerative diseases and injury, is not known. NFs in axons have exceptionally long half-lives in vivo enabling formation of large stable supporting networks, but they can be rapidly degraded during Wallerian degeneration initiated by a limited calpain cleavage. Here, we identify autophagy as a previously unrecognized pathway for NF subunit protein degradation that modulates constitutive and inducible NF turnover in vivo. Levels of NEFL/NF-L, NEFM/NF-M, and NEFH/NF-H subunits rise substantially in neuroblastoma (N2a) cells after blocking autophagy either with the phosphatidylinositol 3-kinase (PtdIns3K) inhibitor 3-methyladenine (3-MA), by depleting ATG5 expression with shRNA, or by using both treatments. In contrast, activating autophagy with rapamycin significantly lowers NF levels in N2a cells. In the mouse brain, NF subunit levels increase in vivo after intracerebroventricular infusion of 3-MA. Furthermore, using tomographic confocal microscopy, immunoelectron microscopy, and biochemical fractionation, we demonstrate the presence of NF proteins intra-lumenally within autophagosomes (APs), autolysosomes (ALs), and lysosomes (LYs). Our findings establish a prominent role for autophagy in NF proteolysis. Autophagy may regulate axon cytoskeleton size and responses of the NF cytoskeleton to injury and disease.
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Affiliation(s)
- Mala V Rao
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA.,Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Sandipkumar Darji
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA
| | - Philip H Stavrides
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA
| | - Chris N Goulbourne
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA
| | - Asok Kumar
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA
| | - Dun-Sheng Yang
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA.,Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Lang Yoo
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA
| | - James Peddy
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA.,Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Ju-Hyun Lee
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA.,Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Aidong Yuan
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA
| | - Ralph A Nixon
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY, USA.,Department of Psychiatry, New York University Langone Medical Center, New York, NY, USA.,Cell Biology, NewYork University Langone Medical Center, NY, USA.,NYU Neuroscience Institute, New York University, New York, NY, USA
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5
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Zhang Q, Fan W, Sun J, Zhang J, Yin Y. Review of Neurofilaments as Biomarkers in Sepsis-Associated Encephalopathy. J Inflamm Res 2023; 16:161-168. [PMID: 36660377 PMCID: PMC9843472 DOI: 10.2147/jir.s391325] [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: 09/26/2022] [Accepted: 12/24/2022] [Indexed: 01/12/2023] Open
Abstract
Sepsis is a common and fatal disease, especially in critically ill patients. Sepsis-associated encephalopathy (SAE) is a diffuse brain dysfunction with acute altered consciousness, permanent cognitive impairment, and even coma, accompanied by sepsis, without direct central nervous system infection. When managing SAE, early identification and quantification of axonal damage facilitate faster and more accurate diagnosis and prognosis. Although no specific markers for SAE have been identified, several biomarkers have been proposed. Neurofilament light chain (NFL) is a highly expressed cytoskeletal component of neurofilament (NF) proteins that can be found in blood and cerebrospinal fluid (CSF) after exposure to axonal injury. NFs can be used as diagnostic and prognostic biomarkers for sepsis-related brain injury. Phosphorylation of NFs contributes to the maturation and stabilization of cytoskeletal structures, especially axons, and facilitates axonal transport, including mitochondrial transport and energy transport. The stability of NF proteins can be assessed by monitoring the expression of NF genes. Furthermore, phosphorylation levels of NFs can be monitored to determine mitochondrial axonal transport associated with cellular energy metabolism at distal axons to assess progression during SAE treatment. This paper provides new insights into the biological characteristics, detection techniques, and scientific achievements of NFs, and discusses the underlying mechanisms and future research directions of NFs in SAE.
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Affiliation(s)
- Qiulei Zhang
- Department of Emergency and Critical Care, The Second Hospital of Jilin University, Changchun, 130021, People’s Republic of China
| | - Weixuan Fan
- Department of Emergency and Critical Care, The Second Hospital of Jilin University, Changchun, 130021, People’s Republic of China
| | - Jian Sun
- Department of Emergency and Critical Care, The Second Hospital of Jilin University, Changchun, 130021, People’s Republic of China
| | - Jingxiao Zhang
- Department of Emergency and Critical Care, The Second Hospital of Jilin University, Changchun, 130021, People’s Republic of China,Correspondence: Jingxiao Zhang; Yongjie Yin, Tel +86-13756314698; +86-13596103459, Email ;
| | - Yongjie Yin
- Department of Emergency and Critical Care, The Second Hospital of Jilin University, Changchun, 130021, People’s Republic of China
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6
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Yuan A, Nixon RA. Posttranscriptional regulation of neurofilament proteins and tau in health and disease. Brain Res Bull 2023; 192:115-127. [PMID: 36441047 PMCID: PMC9907725 DOI: 10.1016/j.brainresbull.2022.10.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 10/20/2022] [Accepted: 10/26/2022] [Indexed: 01/16/2023]
Abstract
Neurofilament and tau proteins are neuron-specific cytoskeletal proteins that are enriched in axons, regulated by many of the same protein kinases, interact physically, and are the principal constituents of neurofibrillary lesions in major adult-onset dementias. Both proteins share functions related to the modulation of stability and functions of the microtubule network in axons, axonal transport and scaffolding of organelles, long-term synaptic potentiation, and learning and memory. Expression of these proteins is regulated not only at the transcriptional level but also through posttranscriptional control of pre-mRNA splicing, mRNA stability, transport, localization, local translation and degradation. Current evidence suggests that posttranscriptional determinants of their levels are usually regulated by RNA-binding proteins and microRNAs primarily through 3'-untranslated regions of neurofilament and tau mRNAs. Dysregulations of neurofilament and tau expression caused by mutations or pathologies of RNA-binding proteins such as TDP43, FUS and microRNAs are increasingly recognized in association with varied neurological disorders. In this review, we summarize the current understanding of posttranscriptional control of neurofilament and tau by examining the posttranscriptional regulation of neurofilament and tau by RNA-binding proteins and microRNAs implicated in health and diseases.
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Affiliation(s)
- Aidong Yuan
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA; NYU Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA.
| | - Ralph A. Nixon
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, NY 10962, USA,Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA,Department of Cell Biology, New York University Langone Health, New York, NY 10016, USA,NYU Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA,Correspondence to: Center for Dementia Research, Nathan Kline Institute, New York University Langone Health, New York, NY 10016, USA, (A. Yuan), (R.A. Nixon)
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7
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Petzold A. The 2022 Lady Estelle Wolfson lectureship on neurofilaments. J Neurochem 2022; 163:179-219. [PMID: 35950263 PMCID: PMC9826399 DOI: 10.1111/jnc.15682] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 01/11/2023]
Abstract
Neurofilament proteins (Nf) have been validated and established as a reliable body fluid biomarker for neurodegenerative pathology. This review covers seven Nf isoforms, Nf light (NfL), two splicing variants of Nf medium (NfM), two splicing variants of Nf heavy (NfH), α -internexin (INA) and peripherin (PRPH). The genetic and epigenetic aspects of Nf are discussed as relevant for neurodegenerative diseases and oncology. The comprehensive list of mutations for all Nf isoforms covers Amyotrophic Lateral Sclerosis, Charcot-Marie Tooth disease, Spinal muscular atrophy, Parkinson Disease and Lewy Body Dementia. Next, emphasis is given to the expanding field of post-translational modifications (PTM) of the Nf amino acid residues. Protein structural aspects are reviewed alongside PTMs causing neurodegenerative pathology and human autoimmunity. Molecular visualisations of NF PTMs, assembly and stoichiometry make use of Alphafold2 modelling. The implications for Nf function on the cellular level and axonal transport are discussed. Neurofilament aggregate formation and proteolytic breakdown are reviewed as relevant for biomarker tests and disease. Likewise, Nf stoichiometry is reviewed with regard to in vitro experiments and as a compensatory mechanism in neurodegeneration. The review of Nf across a spectrum of 87 diseases from all parts of medicine is followed by a critical appraisal of 33 meta-analyses on Nf body fluid levels. The review concludes with considerations for clinical trial design and an outlook for future research.
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Affiliation(s)
- Axel Petzold
- Department of NeurodegenerationQueen Square Insitute of Neurology, UCLLondonUK
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8
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Sainio MT, Rasila T, Molchanova SM, Järvilehto J, Torregrosa-Muñumer R, Harjuhaahto S, Pennonen J, Huber N, Herukka SK, Haapasalo A, Zetterberg H, Taira T, Palmio J, Ylikallio E, Tyynismaa H. Neurofilament Light Regulates Axon Caliber, Synaptic Activity, and Organelle Trafficking in Cultured Human Motor Neurons. Front Cell Dev Biol 2022; 9:820105. [PMID: 35237613 PMCID: PMC8883324 DOI: 10.3389/fcell.2021.820105] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/28/2021] [Indexed: 11/27/2022] Open
Abstract
Neurofilament light (NFL) is one of the proteins forming multimeric neuron-specific intermediate filaments, neurofilaments, which fill the axonal cytoplasm, establish caliber growth, and provide structural support. Dominant missense mutations and recessive nonsense mutations in the neurofilament light gene (NEFL) are among the causes of Charcot–Marie–Tooth (CMT) neuropathy, which affects the peripheral nerves with the longest axons. We previously demonstrated that a neuropathy-causing homozygous nonsense mutation in NEFL led to the absence of NFL in patient-specific neurons. To understand the disease-causing mechanisms, we investigate here the functional effects of NFL loss in human motor neurons differentiated from induced pluripotent stem cells (iPSC). We used genome editing to generate NEFL knockouts and compared them to patient-specific nonsense mutants and isogenic controls. iPSC lacking NFL differentiated efficiently into motor neurons with normal axon growth and regrowth after mechanical axotomy and contained neurofilaments. Electrophysiological analysis revealed that motor neurons without NFL fired spontaneous and evoked action potentials with similar characteristics as controls. However, we found that, in the absence of NFL, human motor neurons 1) had reduced axonal caliber, 2) the amplitude of miniature excitatory postsynaptic currents (mEPSC) was decreased, 3) neurofilament heavy (NFH) levels were reduced and no compensatory increases in other filament subunits were observed, and 4) the movement of mitochondria and to a lesser extent lysosomes was increased. Our findings elaborate the functional roles of NFL in human motor neurons. NFL is not only a structural protein forming neurofilaments and filling the axonal cytoplasm, but our study supports the role of NFL in the regulation of synaptic transmission and organelle trafficking. To rescue the NFL deficiency in the patient-specific nonsense mutant motor neurons, we used three drugs, amlexanox, ataluren (PTC-124), and gentamicin to induce translational read-through or inhibit nonsense-mediated decay. However, the drugs failed to increase the amount of NFL protein to detectable levels and were toxic to iPSC-derived motor neurons.
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Affiliation(s)
- Markus T Sainio
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Tiina Rasila
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Svetlana M Molchanova
- Molecular and Integrative Biosciences Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Julius Järvilehto
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Rubén Torregrosa-Muñumer
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Sandra Harjuhaahto
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jana Pennonen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Nadine Huber
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Sanna-Kaisa Herukka
- Department of Neurology, Kuopio University Hospital, Kuopio, Finland.,Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Annakaisa Haapasalo
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Henrik Zetterberg
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden.,Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden.,Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom.,UK Dementia Research Institute at UCL, London, United Kingdom.,Hong Kong Center for Neurodegenerative Diseases, Hong Kong, Hong Kong SAR, China
| | - Tomi Taira
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, Department of Veterinary Biosciences for Electrophysiology, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Johanna Palmio
- Neuromuscular Research Center, Tampere University Hospital and Tampere University, Tampere, Finland
| | - Emil Ylikallio
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland.,Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.,Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland
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9
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Ghosh A, Singh S. Regulation Of Microtubule: Current Concepts And Relevance To Neurodegenerative Diseases. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2021; 21:656-679. [PMID: 34323203 DOI: 10.2174/1871527320666210728144043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 01/05/2021] [Accepted: 02/23/2021] [Indexed: 11/22/2022]
Abstract
Neurodevelopmental disorders (NDDs) are abnormalities linked to neuronal structure and irregularities associated with the proliferation of cells, transportation, and differentiation. NDD also involves synaptic circuitry and neural network alterations known as synaptopathies. Microtubules (MTs) and MTs-associated proteins help to maintain neuronal health as well as their development. The microtubular dynamic structure plays a crucial role in the division of cells and forms mitotic spindles, thus take part in initiating stages of differentiation and polarization for various types of cells. The MTs also take part in the cellular death but MT-based cellular degenerations are not yet well excavated. In the last few years, studies have provided the protagonist activity of MTs in neuronal degeneration. In this review, we largely engrossed our discussion on the change of MT cytoskeleton structure, describing their organization, dynamics, transportation, and their failure causing NDDs. At end of this review, we are targeting the therapeutic neuroprotective strategies on clinical priority and also try to discuss the clues for the development of new MT-based therapy as a new pharmacological intervention. This will be a new potential site to block not only neurodegeneration but also promotes the regeneration of neurons.
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Affiliation(s)
- Anirban Ghosh
- Neuroscience Division, Department of Pharmacology, ISF College of Pharmacy, Moga-142001 Punjab, India
| | - Shamsher Singh
- Neuroscience Division, Department of Pharmacology, ISF College of Pharmacy, Moga-142001 Punjab, India
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10
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Khan MI, Hasan F, Mahmud KAHA, Adnan A. Viscoelastic Response of Neurofilaments: An Atomistic Simulation Approach. Biomolecules 2021; 11:biom11040540. [PMID: 33917073 PMCID: PMC8067762 DOI: 10.3390/biom11040540] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/29/2021] [Accepted: 04/05/2021] [Indexed: 12/05/2022] Open
Abstract
Existent literature has limitations regarding the mechanical behavior of axonal cytoskeletal components in a high strain rate scenario, which is mainly due to limitations regarding the structure of some components such as tau protein and neurofilaments (NF). This study performs molecular dynamics (MD) simulations on NFs to extract their strain rate-dependent behavior. It is found that they are highly stretchable and show multiple stages of unfolding. Furthermore, NFs show high tensile stiffness. Also, viscoelastic modeling shows that they correspond to simplified viscoelastic models. This study effectively enhances the existent axonal models focusing on axonal injury.
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11
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TSUBOI M, HIRABAYASHI Y. New insights into the regulation of synaptic transmission and plasticity by the endoplasmic reticulum and its membrane contacts. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2021; 97:559-572. [PMID: 34897182 PMCID: PMC8687855 DOI: 10.2183/pjab.97.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 10/18/2021] [Indexed: 06/14/2023]
Abstract
Mammalian neurons are highly compartmentalized yet very large cells. To provide each compartment with its distinct properties, metabolic homeostasis and molecular composition need to be precisely coordinated in a compartment-specific manner. Despite the importance of the endoplasmic reticulum (ER) as a platform for various biochemical reactions, such as protein synthesis, protein trafficking, and intracellular calcium control, the contribution of the ER to neuronal compartment-specific functions and plasticity remains elusive. Recent advances in the development of live imaging and serial scanning electron microscopy (sSEM) analysis have revealed that the neuronal ER is a highly dynamic organelle with compartment-specific structures. sSEM studies also revealed that the ER forms contacts with other membranes, such as the mitochondria and plasma membrane, although little is known about the functions of these ER-membrane contacts. In this review, we discuss the mechanisms and physiological roles of the ER structure and ER-mitochondria contacts in synaptic transmission and plasticity, thereby highlighting a potential link between organelle ultrastructure and neuronal functions.
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Affiliation(s)
- Masafumi TSUBOI
- Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
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12
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Abstract
It is increasingly recognized that local protein synthesis (LPS) contributes to fundamental aspects of axon biology, in both developing and mature neurons. Mutations in RNA-binding proteins (RBPs), as central players in LPS, and other proteins affecting RNA localization and translation are associated with a range of neurological disorders, suggesting disruption of LPS may be of pathological significance. In this review, we substantiate this hypothesis by examining the link between LPS and key axonal processes, and the implicated pathophysiological consequences of dysregulated LPS. First, we describe how the length and autonomy of axons result in an exceptional reliance on LPS. We next discuss the roles of LPS in maintaining axonal structural and functional polarity and axonal trafficking. We then consider how LPS facilitates the establishment of neuronal connectivity through regulation of axonal branching and pruning, how it mediates axonal survival into adulthood and its involvement in neuronal stress responses.
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Affiliation(s)
- Julie Qiaojin Lin
- UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Island Research Building, Cambridge Biomedical Campus, Cambridge, UK
| | | | - Christine E Holt
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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13
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Guillaud L, El-Agamy SE, Otsuki M, Terenzio M. Anterograde Axonal Transport in Neuronal Homeostasis and Disease. Front Mol Neurosci 2020; 13:556175. [PMID: 33071754 PMCID: PMC7531239 DOI: 10.3389/fnmol.2020.556175] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022] Open
Abstract
Neurons are highly polarized cells with an elongated axon that extends far away from the cell body. To maintain their homeostasis, neurons rely extensively on axonal transport of membranous organelles and other molecular complexes. Axonal transport allows for spatio-temporal activation and modulation of numerous molecular cascades, thus playing a central role in the establishment of neuronal polarity, axonal growth and stabilization, and synapses formation. Anterograde and retrograde axonal transport are supported by various molecular motors, such as kinesins and dynein, and a complex microtubule network. In this review article, we will primarily discuss the molecular mechanisms underlying anterograde axonal transport and its role in neuronal development and maturation, including the establishment of functional synaptic connections. We will then provide an overview of the molecular and cellular perturbations that affect axonal transport and are often associated with axonal degeneration. Lastly, we will relate our current understanding of the role of axonal trafficking concerning anterograde trafficking of mRNA and its involvement in the maintenance of the axonal compartment and disease.
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Affiliation(s)
- Laurent Guillaud
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Sara Emad El-Agamy
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Miki Otsuki
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Marco Terenzio
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
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14
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Beijer D, Sisto A, Van Lent J, Baets J, Timmerman V. Defects in Axonal Transport in Inherited Neuropathies. J Neuromuscul Dis 2020; 6:401-419. [PMID: 31561383 PMCID: PMC6918914 DOI: 10.3233/jnd-190427] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Axonal transport is a highly complex process essential for sustaining proper neuronal functioning. Disturbances can result in an altered neuronal homeostasis, aggregation of cargoes, and ultimately a dying-back degeneration of neurons. The impact of dysfunction in axonal transport is shown by genetic defects in key proteins causing a broad spectrum of neurodegenerative diseases, including inherited peripheral neuropathies. In this review, we provide an overview of the cytoskeletal components, molecular motors and adaptor proteins involved in axonal transport mechanisms and their implication in neuronal functioning. In addition, we discuss the involvement of axonal transport dysfunction in neurodegenerative diseases with a particular focus on inherited peripheral neuropathies. Lastly, we address some recent scientific advances most notably in therapeutic strategies employed in the area of axonal transport, patient-derived iPSC models, in vivo animal models, antisense-oligonucleotide treatments, and novel chemical compounds.
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Affiliation(s)
- Danique Beijer
- Neurogenetics Research Group, Department of Medical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium
| | - Angela Sisto
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium
| | - Jonas Van Lent
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium
| | - Jonathan Baets
- Neurogenetics Research Group, Department of Medical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium.,Neurology Department, University Hospital Antwerp, Antwerpen, Belgium
| | - Vincent Timmerman
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerpen, Belgium.,Neurogenetics Laboratory, Institute Born Bunge, Antwerpen, Belgium
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15
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Bott CJ, Winckler B. Intermediate filaments in developing neurons: Beyond structure. Cytoskeleton (Hoboken) 2020; 77:110-128. [PMID: 31970897 DOI: 10.1002/cm.21597] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/06/2020] [Accepted: 01/08/2020] [Indexed: 12/20/2022]
Abstract
Neuronal development relies on a highly choreographed progression of dynamic cellular processes by which newborn neurons migrate, extend axons and dendrites, innervate their targets, and make functional synapses. Many of these dynamic processes require coordinated changes in morphology, powered by the cell's cytoskeleton. Intermediate filaments (IFs) are the third major cytoskeletal elements in vertebrate cells, but are rarely considered when it comes to understanding axon and dendrite growth, pathfinding and synapse formation. In this review, we first introduce the many new and exciting concepts of IF function, discovered mostly in non-neuronal cells. These roles include dynamic rearrangements, crosstalk with microtubules and actin filaments, mechano-sensing and -transduction, and regulation of signaling cascades. We then discuss the understudied roles of neuronally expressed IFs, with a particular focus on IFs expressed during development, such as nestin, vimentin and α-internexin. Lastly, we illustrate how signaling modulation by the unconventional IF nestin shapes neuronal morphogenesis in unexpected and novel ways. Even though the first IF knockout mice were made over 20 years ago, the study of the cell biological functions of IFs in the brain still has much room for exciting new discoveries.
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Affiliation(s)
- Christopher J Bott
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia
| | - Bettina Winckler
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia
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16
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Roles for the Endoplasmic Reticulum in Regulation of Neuronal Calcium Homeostasis. Cells 2019; 8:cells8101232. [PMID: 31658749 PMCID: PMC6829861 DOI: 10.3390/cells8101232] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/01/2019] [Accepted: 10/03/2019] [Indexed: 02/06/2023] Open
Abstract
By influencing Ca2+ homeostasis in spatially and architecturally distinct neuronal compartments, the endoplasmic reticulum (ER) illustrates the notion that form and function are intimately related. The contribution of ER to neuronal Ca2+ homeostasis is attributed to the organelle being the largest reservoir of intracellular Ca2+ and having a high density of Ca2+ channels and transporters. As such, ER Ca2+ has incontrovertible roles in the regulation of axodendritic growth and morphology, synaptic vesicle release, and neural activity dependent gene expression, synaptic plasticity, and mitochondrial bioenergetics. Not surprisingly, many neurological diseases arise from ER Ca2+ dyshomeostasis, either directly due to alterations in ER resident proteins, or indirectly via processes that are coupled to the regulators of ER Ca2+ dynamics. In this review, we describe the mechanisms involved in the establishment of ER Ca2+ homeostasis in neurons. We elaborate upon how changes in the spatiotemporal dynamics of Ca2+ exchange between the ER and other organelles sculpt neuronal function and provide examples that demonstrate the involvement of ER Ca2+ dyshomeostasis in a range of neurological and neurodegenerative diseases.
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17
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Khan LA, Jafari G, Zhang N, Membreno E, Yan S, Zhang H, Gobel V. A tensile trilayered cytoskeletal endotube drives capillary-like lumenogenesis. J Cell Biol 2019; 218:2403-2424. [PMID: 31239283 PMCID: PMC6605810 DOI: 10.1083/jcb.201811175] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 04/09/2019] [Accepted: 05/14/2019] [Indexed: 01/01/2023] Open
Abstract
Unicellular tubes are components of internal organs and capillaries. It is unclear how they meet the architectural challenge to extend a centered intracellular lumen of uniform diameter. In an RNAi-based Caenorhabditis elegans screen, we identified three intermediate filaments (IFs)-IFA-4, IFB-1, and IFC-2-as interactors of the lumenal membrane-actin linker ERM-1 in excretory-canal tubulogenesis. We find that IFs, generally thought to affect morphogenesis indirectly by maintaining tissue integrity, directly promote lumenogenesis in this capillary-like single-cell tube. We show that ERM-1, ACT-5/actin, and TBB-2/tubulin recruit membrane-forming endosomal and flux-promoting canalicular vesicles to the lumen, whereas IFs, themselves recruited to the lumen by ERM-1 and TBB-2, restrain lateral vesicle access. IFs thereby prevent cystogenesis, equilibrate the lumen diameter, and promote lumen forward extension. Genetic and imaging analyses suggest that IFB-1/IFA-4 and IFB-1/IFC-2 polymers form a perilumenal triple IF lattice, sandwiched between actin and helical tubulin. Our findings characterize a novel mechanism of capillary-like lumenogenesis, where a tensile trilayered cytoskeletal endotube transforms concentric into directional growth.
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Affiliation(s)
- Liakot A Khan
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA
| | - Gholamali Jafari
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA
| | - Nan Zhang
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA
- Key Laboratory of Zoonosis Research, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun, China
| | - Edward Membreno
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA
| | - Siyang Yan
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA
| | - Hongjie Zhang
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA
- Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Verena Gobel
- Mucosal Immunology and Biology Research Center, Developmental Biology and Genetics Core, Massachusetts General Hospital for Children, Harvard Medical School, Boston, MA
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18
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Didonna A, Opal P. The role of neurofilament aggregation in neurodegeneration: lessons from rare inherited neurological disorders. Mol Neurodegener 2019; 14:19. [PMID: 31097008 PMCID: PMC6524292 DOI: 10.1186/s13024-019-0318-4] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 04/26/2019] [Indexed: 12/13/2022] Open
Abstract
Many neurodegenerative disorders, including Parkinson's, Alzheimer's, and amyotrophic lateral sclerosis, are well known to involve the accumulation of disease-specific proteins. Less well known are the accumulations of another set of proteins, neuronal intermediate filaments (NFs), which have been observed in these diseases for decades. NFs belong to the family of cytoskeletal intermediate filament proteins (IFs) that give cells their shape; they determine axonal caliber, which controls signal conduction; and they regulate the transport of synaptic vesicles and modulate synaptic plasticity by binding to neurotransmitter receptors. In the last two decades, a number of rare disorders caused by mutations in genes that encode NFs or regulate their metabolism have been discovered. These less prevalent disorders are providing novel insights into the role of NF aggregation in the more common neurological disorders.
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Affiliation(s)
- Alessandro Didonna
- Department of Neurology and Weill Institute for Neurosciences, University of California at San Francisco, San Francisco, CA, 94158, USA
| | - Puneet Opal
- Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA. .,Department of Cell and Molecular Biology, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA.
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19
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Rodrigues ACZ, Messi ML, Wang ZM, Abba MC, Pereyra A, Birbrair A, Zhang T, O’Meara M, Kwan P, Lopez EIS, Willis MS, Mintz A, Files DC, Furdui C, Oppenheim RW, Delbono O. The sympathetic nervous system regulates skeletal muscle motor innervation and acetylcholine receptor stability. Acta Physiol (Oxf) 2019; 225:e13195. [PMID: 30269419 PMCID: PMC7224611 DOI: 10.1111/apha.13195] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 09/23/2018] [Accepted: 09/26/2018] [Indexed: 12/19/2022]
Abstract
AIM Symptoms of autonomic failure are frequently the presentation of advanced age and neurodegenerative diseases that impair adaptation to common physiologic stressors. The aim of this work was to examine the interaction between the sympathetic and motor nervous system, the involvement of the sympathetic nervous system (SNS) in neuromuscular junction (NMJ) presynaptic motor function, the stability of postsynaptic molecular organization, and the skeletal muscle composition and function. METHODS Since muscle weakness is a symptom of diseases characterized by autonomic dysfunction, we studied the impact of regional sympathetic ablation on muscle motor innervation by using transcriptome analysis, retrograde tracing of the sympathetic outflow to the skeletal muscle, confocal and electron microscopy, NMJ transmission by electrophysiological methods, protein analysis, and state of the art microsurgical techniques, in C57BL6, MuRF1KO and Thy-1 mice. RESULTS We found that the SNS regulates motor nerve synaptic vesicle release, skeletal muscle transcriptome, muscle force generated by motor nerve activity, axonal neurofilament phosphorylation, myelin thickness, and myofibre subtype composition and CSA. The SNS also modulates the levels of postsynaptic membrane acetylcholine receptor by regulating the Gαi2 -Hdac4-Myogenin-MuRF1pathway, which is prevented by the overexpression of the guanine nucleotide-binding protein Gαi2 (Q205L), a constitutively active mutant G protein subunit. CONCLUSION The SNS regulates NMJ transmission, maintains optimal Gαi2 expression, and prevents any increase in Hdac4, myogenin, MuRF1, and miR-206. SNS ablation leads to upregulation of MuRF1, muscle atrophy, and downregulation of postsynaptic AChR. Our findings are relevant to clinical conditions characterized by progressive decline of sympathetic innervation, such as neurodegenerative diseases and aging.
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Affiliation(s)
- Anna C. Z. Rodrigues
- Department of Internal Medicine, Gerontology, Wake Forest School of Medicine, Winston-Salem, North Carolina
- Neuroscience Program, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Maria L. Messi
- Department of Internal Medicine, Gerontology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Zhong-Min Wang
- Department of Internal Medicine, Gerontology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Martin C. Abba
- Basic and Applied Immunological Research Center (CINIBA), School of Medicine, National University of La Plata, Buenos Aires, Argentina
| | - Andrea Pereyra
- Department of Internal Medicine, Gerontology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Alexander Birbrair
- Department of Internal Medicine, Gerontology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Tan Zhang
- Department of Internal Medicine, Gerontology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Meaghan O’Meara
- Department of Internal Medicine, Gerontology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Ping Kwan
- Department of Internal Medicine, Gerontology, Wake Forest School of Medicine, Winston-Salem, North Carolina
- Neuroscience Program, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Elsa I. S. Lopez
- Department of Internal Medicine, Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Monte S. Willis
- Department of Pathology, McAllister Heart Institute, University of North Carolina-Chapel Hill, Chapel Hill, North Carolina
| | - Akiva Mintz
- Department of Radiology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - D. Clark Files
- Department of Internal Medicine, Gerontology, Wake Forest School of Medicine, Winston-Salem, North Carolina
- Department of Internal Medicine, Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
- Department of Internal Medicine, Pulmonary, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Cristina Furdui
- Department of Internal Medicine, Molecular Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Ronald W. Oppenheim
- Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Osvaldo Delbono
- Department of Internal Medicine, Gerontology, Wake Forest School of Medicine, Winston-Salem, North Carolina
- Neuroscience Program, Wake Forest School of Medicine, Winston-Salem, North Carolina
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20
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Pierozan P, Pessoa-Pureur R. Cytoskeleton as a Target of Quinolinic Acid Neurotoxicity: Insight from Animal Models. Mol Neurobiol 2017. [PMID: 28647871 DOI: 10.1007/s12035-017-0654-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cytoskeletal proteins are increasingly recognized as having important roles as a target of the action of different neurotoxins. In the last years, several works of our group have shown that quinolinic acid (QUIN) was able to disrupt the homeostasis of the cytoskeleton of neural cells and this was associated with cell dysfunction and neurodegeneration. QUIN is an excitotoxic metabolite of tryptophan metabolism and its accumulation is associated with several neurodegenerative diseases. In the present review, we provide a comprehensive view of the actions of QUIN upstream of glutamate receptors, eliciting kinase/phosphatase signaling cascades that disrupt the homeostasis of the phosphorylation system associated with intermediate filament proteins of astrocytes and neurons. We emphasize the critical role of calcium in these actions and the evidence that misregulated cytoskeleton takes part of the cell response to the injury resulting in neurodegeneration in different brain regions, disrupted cell signaling in acute tissue slices, and disorganized cytoskeleton with altered cell morphology in primary cultures. We also discuss the interplay among misregulated cytoskeleton, oxidative stress, and cell-cell contact through gap junctions mediating the quinolinic acid injury in rat brain. The increasing amount of cross talks identified between cytoskeletal proteins and cellular signaling cascades reinforces the exciting possibility that cytoskeleton could be a new target in the neurotoxicity of QUIN and further studies will be necessary to develop strategies to protect the cytoskeleton and counteracts the cytotoxicity of this metabolite.
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Affiliation(s)
- Paula Pierozan
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600 Anexo, Porto Alegre, RS, 90035-003, Brazil
| | - Regina Pessoa-Pureur
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600 Anexo, Porto Alegre, RS, 90035-003, Brazil.
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21
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Leube RE, Moch M, Windoffer R. Intracellular Motility of Intermediate Filaments. Cold Spring Harb Perspect Biol 2017; 9:9/6/a021980. [PMID: 28572456 DOI: 10.1101/cshperspect.a021980] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
SUMMARYThe establishment and continuous cell type-specific adaptation of cytoplasmic intermediate filament (IF) networks are linked to various types of IF motility. Motor protein-driven active transport, linkage to other cellular structures, diffusion of small soluble subunits, and intrinsic network elasticity all contribute to the motile behavior of IFs. These processes are subject to regulation by multiple signaling pathways. IF motility is thereby connected to and involved in many basic cellular processes guarding the maintenance of cell and tissue integrity. Disturbances of IF motility are linked to diseases that are characterized by cytoplasmic aggregates containing IF proteins together with other cellular components.
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Affiliation(s)
- Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Marcin Moch
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
| | - Reinhard Windoffer
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52074 Aachen, Germany
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22
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Kirkcaldie MTK, Dwyer ST. The third wave: Intermediate filaments in the maturing nervous system. Mol Cell Neurosci 2017; 84:68-76. [PMID: 28554564 DOI: 10.1016/j.mcn.2017.05.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 05/10/2017] [Accepted: 05/25/2017] [Indexed: 01/16/2023] Open
Abstract
Intermediate filaments are critical for the extreme structural specialisations of neurons, providing integrity in dynamic environments and efficient communication along axons a metre or more in length. As neurons mature, an initial expression of nestin and vimentin gives way to the neurofilament triplet proteins and α-internexin, substituted by peripherin in axons outside the CNS, which physically consolidate axons as they elongate and find their targets. Once connection is established, these proteins are transported, assembled, stabilised and modified, structurally transforming axons and dendrites as they acquire their full function. The interaction between these neurons and myelinating glial cells optimises the structure of axons for peak functional efficiency, a property retained across their lifespan. This finely calibrated structural regulation allows the nervous system to maintain timing precision and efficient control across large distances throughout somatic growth and, in maturity, as a plasticity mechanism allowing functional adaptation.
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Affiliation(s)
- Matthew T K Kirkcaldie
- School of Medicine, Wicking Dementia Research and Education Centre, Faculty of Health, University of Tasmania, Australia.
| | - Samuel T Dwyer
- School of Medicine, Wicking Dementia Research and Education Centre, Faculty of Health, University of Tasmania, Australia
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23
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Yuan A, Rao MV, Veeranna, Nixon RA. Neurofilaments and Neurofilament Proteins in Health and Disease. Cold Spring Harb Perspect Biol 2017; 9:9/4/a018309. [PMID: 28373358 DOI: 10.1101/cshperspect.a018309] [Citation(s) in RCA: 419] [Impact Index Per Article: 59.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
SUMMARYNeurofilaments (NFs) are unique among tissue-specific classes of intermediate filaments (IFs) in being heteropolymers composed of four subunits (NF-L [neurofilament light]; NF-M [neurofilament middle]; NF-H [neurofilament heavy]; and α-internexin or peripherin), each having different domain structures and functions. Here, we review how NFs provide structural support for the highly asymmetric geometries of neurons and, especially, for the marked radial expansion of myelinated axons crucial for effective nerve conduction velocity. NFs in axons extensively cross-bridge and interconnect with other non-IF components of the cytoskeleton, including microtubules, actin filaments, and other fibrous cytoskeletal elements, to establish a regionally specialized network that undergoes exceptionally slow local turnover and serves as a docking platform to organize other organelles and proteins. We also discuss how a small pool of oligomeric and short filamentous precursors in the slow phase of axonal transport maintains this network. A complex pattern of phosphorylation and dephosphorylation events on each subunit modulates filament assembly, turnover, and organization within the axonal cytoskeleton. Multiple factors, and especially turnover rate, determine the size of the network, which can vary substantially along the axon. NF gene mutations cause several neuroaxonal disorders characterized by disrupted subunit assembly and NF aggregation. Additional NF alterations are associated with varied neuropsychiatric disorders. New evidence that subunits of NFs exist within postsynaptic terminal boutons and influence neurotransmission suggests how NF proteins might contribute to normal synaptic function and neuropsychiatric disease states.
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Affiliation(s)
- Aidong Yuan
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York 10962.,Department of Psychiatry, New York University School of Medicine, New York, New York 10016
| | - Mala V Rao
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York 10962.,Department of Psychiatry, New York University School of Medicine, New York, New York 10016
| | - Veeranna
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York 10962.,Department of Psychiatry, New York University School of Medicine, New York, New York 10016
| | - Ralph A Nixon
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York 10962.,Department of Psychiatry, New York University School of Medicine, New York, New York 10016.,Cell Biology, New York University School of Medicine, New York, New York 10016
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25
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Vickers J, Kirkcaldie M, Phipps A, King A. Alterations in neurofilaments and the transformation of the cytoskeleton in axons may provide insight into the aberrant neuronal changes of Alzheimer’s disease. Brain Res Bull 2016; 126:324-333. [DOI: 10.1016/j.brainresbull.2016.07.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 01/09/2023]
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Yuan A, Nixon RA. Specialized roles of neurofilament proteins in synapses: Relevance to neuropsychiatric disorders. Brain Res Bull 2016; 126:334-346. [PMID: 27609296 PMCID: PMC5079776 DOI: 10.1016/j.brainresbull.2016.09.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 09/02/2016] [Accepted: 09/03/2016] [Indexed: 01/05/2023]
Abstract
Neurofilaments are uniquely complex among classes of intermediate filaments in being composed of four subunits (NFL, NFM, NFH and alpha-internexin in the CNS) that differ in structure, regulation, and function. Although neurofilaments have been traditionally viewed as axonal structural components, recent evidence has revealed that distinctive assemblies of neurofilament subunits are integral components of synapses, especially at postsynaptic sites. Within the synaptic compartment, the individual subunits differentially modulate neurotransmission and behavior through interactions with specific neurotransmitter receptors. These newly uncovered functions suggest that alterations of neurofilament proteins not only underlie axonopathy in various neurological disorders but also may play vital roles in cognition and neuropsychiatric diseases. Here, we review evidence that synaptic neurofilament proteins are a sizable population in the CNS and we advance the concept that changes in the levels or post-translational modification of individual NF subunits contribute to synaptic and behavioral dysfunction in certain neuropsychiatric conditions.
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Affiliation(s)
- Aidong Yuan
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, 10962, United States; Departments of Psychiatry, New York University School of Medicine, New York, NY, 10016, United States.
| | - Ralph A Nixon
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, 10962, United States; Departments of Psychiatry, New York University School of Medicine, New York, NY, 10016, United States; Department of Cell Biology, New York University School of Medicine, New York, NY, 10016, United States.
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Kirkcaldie MTK, Collins JM. The axon as a physical structure in health and acute trauma. J Chem Neuroanat 2016; 76:9-18. [PMID: 27233660 DOI: 10.1016/j.jchemneu.2016.05.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 05/22/2016] [Accepted: 05/22/2016] [Indexed: 10/21/2022]
Abstract
The physical structure of neurons - dendrites converging on the soma, with an axon conveying activity to distant locations - is uniquely tied to their function. To perform their role, axons need to maintain structural precision in the soft, gelatinous environment of the central nervous system and the dynamic, flexible paths of nerves in the periphery. This requires close mechanical coupling between axons and the surrounding tissue, as well as an elastic, robust axoplasm resistant to pinching and flattening, and capable of sustaining transport despite physical distortion. These mechanical properties arise primarily from the properties of the internal cytoskeleton, coupled to the axonal membrane and the extracellular matrix. In particular, the two large constituents of the internal cytoskeleton, microtubules and neurofilaments, are braced against each other and flexibly interlinked by specialised proteins. Recent evidence suggests that the primary function of neurofilament sidearms is to structure the axoplasm into a linearly organised, elastic gel. This provides support and structure to the contents of axons in peripheral nerves subject to bending, protecting the relatively brittle microtubule bundles and maintaining them as transport conduits. Furthermore, a substantial proportion of axons are myelinated, and this thick jacket of membrane wrappings alters the form, function and internal composition of the axons to which it is applied. Together these structures determine the physical properties and integrity of neural tissue, both under conditions of normal movement, and in response to physical trauma. The effects of traumatic injury are directly dependent on the physical properties of neural tissue, especially axons, and because of axons' extreme structural specialisation, post-traumatic effects are usually characterised by particular modes of axonal damage. The physical realities of axons in neural tissue are integral to both normal function and their response to injury, and require specific consideration in evaluating research models of neurotrauma.
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Affiliation(s)
- Matthew T K Kirkcaldie
- School of Medicine, University of Tasmania, Australia; Wicking Dementia Research and Education Centre, Faculty of Health, University of Tasmania, Australia.
| | - Jessica M Collins
- Wicking Dementia Research and Education Centre, Faculty of Health, University of Tasmania, Australia
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Gentil BJ, Tibshirani M, Durham HD. Neurofilament dynamics and involvement in neurological disorders. Cell Tissue Res 2015; 360:609-20. [PMID: 25567110 DOI: 10.1007/s00441-014-2082-7] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 11/19/2014] [Indexed: 12/21/2022]
Abstract
Neurons are extremely polarised cells in which the cytoskeleton, composed of microtubules, microfilaments and neurofilaments, plays a crucial role in maintaining structure and function. Neurofilaments, the 10-nm intermediate filaments of neurons, provide structure and mechanoresistance but also provide a scaffolding for the organization of the nucleus and organelles such as mitochondria and ER. Disruption of neurofilament organization and expression or metabolism of neurofilament proteins is characteristic of certain neurological syndromes including Amyotrophic Lateral Sclerosis, Charcot-Marie-Tooth sensorimotor neuropathies and Giant Axonal Neuropathy. Microfluorometric live imaging techniques have been instrumental in revealing the dynamics of neurofilament assembly and transport and their functions in organizing intracellular organelle networks. The insolubility of neurofilament proteins has limited identifying interactors by conventional biochemical techniques but yeast two-hybrid experiments have revealed new roles for oligomeric, nonfilamentous structures including vesicular trafficking. Although having long half-lives, new evidence points to degradation of subunits by the ubiquitin-proteasome system as a mechanism of normal turnover. Although certain E3-ligases ubiquitinating neurofilament proteins have been identified, the overall process of neurofilament degradation is not well understood. We review these mechanisms of neurofilament homeostasis and abnormalities in motor neuron and peripheral nerve disorders. Much remains to discover about the disruption of processes that leads to their pathological aggregation and accumulation and the relevance to pathogenesis. Understanding these mechanisms is crucial for identifying novel therapeutic strategies.
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Affiliation(s)
- Benoit J Gentil
- Department of Neurology/Neurosurgery and Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4, Canada,
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29
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Larivière R, Gaudet R, Gentil BJ, Girard M, Conte TC, Minotti S, Leclerc-Desaulniers K, Gehring K, McKinney RA, Shoubridge EA, McPherson PS, Durham HD, Brais B. Sacs knockout mice present pathophysiological defects underlying autosomal recessive spastic ataxia of Charlevoix-Saguenay. Hum Mol Genet 2014; 24:727-39. [PMID: 25260547 DOI: 10.1093/hmg/ddu491] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS [MIM 270550]) is an early-onset neurodegenerative disorder caused by mutations in the SACS gene. Over 170 SACS mutations have been reported worldwide and are thought to cause loss of function of sacsin, a poorly characterized and massive 520 kDa protein. To establish an animal model and to examine the pathophysiological basis of ARSACS, we generated Sacs knockout (Sacs(-/-)) mice. Null animals displayed an abnormal gait with progressive motor, cerebellar and peripheral nerve dysfunctions highly reminiscent of ARSACS. These clinical features were accompanied by an early onset, progressive loss of cerebellar Purkinje cells followed by spinal motor neuron loss and peripheral neuropathy. Importantly, loss of sacsin function resulted in abnormal accumulation of non-phosphorylated neurofilament (NF) bundles in the somatodendritic regions of vulnerable neuronal populations, a phenotype also observed in an ARSACS brain. Moreover, motor neurons cultured from Sacs(-/-) embryos exhibited a similar NF rearrangement with significant reduction in mitochondrial motility and elongated mitochondria. The data points to alterations in the NF cytoskeleton and defects in mitochondrial dynamics as the underlying pathophysiological basis of ARSACS.
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Affiliation(s)
- Roxanne Larivière
- Department of Neurology and Neurosurgery, Laboratory of Neurogenetics of Motion and
| | - Rébecca Gaudet
- Department of Neurology and Neurosurgery, Laboratory of Neurogenetics of Motion and
| | - Benoit J Gentil
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada H3A 2B4
| | - Martine Girard
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada H3A 2B4
| | | | - Sandra Minotti
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada H3A 2B4
| | | | - Kalle Gehring
- Groupe de Recherche Axé sur la Structure des Protéines, Department of Biochemistry and
| | - R Anne McKinney
- Department of Pharmacology, McGill University, Montreal, QC, Canada H3G 0B1
| | - Eric A Shoubridge
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada H3A 2B4
| | - Peter S McPherson
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada H3A 2B4
| | - Heather D Durham
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC, Canada H3A 2B4
| | - Bernard Brais
- Department of Neurology and Neurosurgery, Laboratory of Neurogenetics of Motion and
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González C, Couve A. The axonal endoplasmic reticulum and protein trafficking: Cellular bootlegging south of the soma. Semin Cell Dev Biol 2013; 27:23-31. [PMID: 24361785 DOI: 10.1016/j.semcdb.2013.12.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 11/18/2013] [Accepted: 12/05/2013] [Indexed: 12/26/2022]
Abstract
Neurons are responsible for the generation and propagation of electrical impulses, which constitute the central mechanism of information transfer between the nervous system and internal or external environments. Neurons are large and polarized cells with dendrites and axons constituting their major functional domains. Axons are thin and extremely long specializations that mediate the conduction of these electrical impulses. Regulation of the axonal proteome is fundamental to generate and maintain neural function. Although classical mechanisms of protein transport have been around for decades, a variety newly identified mechanisms to control the abundance of axonal proteins have appeared in recent years. Here we briefly describe the classical models of axonal transport and compare them to the emerging concepts of axonal biosynthesis centered on the endoplasmic reticulum. We review the structure of the axonal endoplasmic reticulum, and its role in diffusion and trafficking of axonal proteins. We also analyze the contribution of other secretory organelles to axonal trafficking and evaluate the potential consequences of axonal endoplasmic reticulum malfunction in neuropathology.
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Affiliation(s)
- Carolina González
- Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM) and Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Andrés Couve
- Program of Physiology and Biophysics, Institute of Biomedical Sciences (ICBM) and Biomedical Neuroscience Institute (BNI), Faculty of Medicine, Universidad de Chile, Santiago, Chile.
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32
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Kanno TYN, Espreafico EM, Yan CYI. Role of myosin Va in neuritogenesis of chick dorsal root ganglia nociceptive neurons. Cell Biol Int 2013; 38:388-94. [DOI: 10.1002/cbin.10210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 10/19/2013] [Indexed: 01/24/2023]
Affiliation(s)
- Tatiane Y. N. Kanno
- Department of Cell and Developmental Biology; Institute of Biomedical Sciences; University of São Paulo; São Paulo SP Brazil
| | - Enilza M. Espreafico
- Department of Cell and Molecular Biology; Faculty of Medicine of Ribeirão Preto; University of São Paulo; Ribeirão Preto SP Brazil
| | - Chao Yun Irene Yan
- Department of Cell and Developmental Biology; Institute of Biomedical Sciences; University of São Paulo; São Paulo SP Brazil
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Subbanna S, Nagre NN, Shivakumar M, Umapathy NS, Psychoyos D, Basavarajappa BS. Ethanol induced acetylation of histone at G9a exon1 and G9a-mediated histone H3 dimethylation leads to neurodegeneration in neonatal mice. Neuroscience 2013; 258:422-32. [PMID: 24300108 DOI: 10.1016/j.neuroscience.2013.11.043] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 11/19/2013] [Accepted: 11/20/2013] [Indexed: 11/16/2022]
Abstract
The transient exposure of immature rodents to ethanol during postnatal day 7 (P7), comparable to a time point within the third trimester of human pregnancy, induces neurodegeneration. However, the molecular mechanisms underlying the deleterious effects of ethanol on the developing brain are poorly understood. In our previous study, we showed that a high dose administration of ethanol at P7 enhances G9a and leads to caspase-3-mediated degradation of dimethylated H3 on lysine 9 (H3K9me2). In this study, we investigated the potential role of epigenetic changes at G9a exon1, G9a-mediated H3 dimethylation on neurodegeneration and G9a-associated proteins in the P7 brain following exposure to a low dose of ethanol. We found that a low dose of ethanol induces mild neurodegeneration in P7 mice, enhances specific acetylation of H3 on lysine 14 (H3K14ace) at G9a exon1, G9a protein levels, augments the dimethylation of H3K9 and H3 lysine 27 (H3K27me2). However, neither dimethylated H3K9 nor K27 underwent degradation. Pharmacological inhibition of G9a activity prior to ethanol treatment prevented H3 dimethylation and neurodegeneration. Further, our immunoprecipitation data suggest that G9a directly associates with DNA methyltransferase (DNMT3A) and methyl-CpG-binding protein 2 (MeCP2). In addition, DNMT3A and MeCP2 protein levels were enhanced by a low dose of ethanol that was shown to induce mild neurodegeneration. Collectively, these epigenetic alterations lead to association of G9a, DNMT3A and MeCP2 to form a larger repressive complex and have a significant role in low-dose ethanol-induced neurodegeneration in the developing brain.
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Affiliation(s)
- S Subbanna
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - N N Nagre
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - M Shivakumar
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - N S Umapathy
- Vascular Biology Center, Georgia Regents University, Augusta, GA 30912, USA
| | - D Psychoyos
- Institute of Biosciences and Technology, Houston, Texas A&M University Health Science Center, Houston, TX 77030, USA
| | - B S Basavarajappa
- Division of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; New York State Psychiatric Institute, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA; Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA.
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34
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Affiliation(s)
- Aidong Yuan
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, NY 10962, USA.
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35
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36
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37
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Rao MV, Yuan A, Campbell J, Kumar A, Nixon RA. The C-terminal domains of NF-H and NF-M subunits maintain axonal neurofilament content by blocking turnover of the stationary neurofilament network. PLoS One 2012; 7:e44320. [PMID: 23028520 PMCID: PMC3448626 DOI: 10.1371/journal.pone.0044320] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 08/01/2012] [Indexed: 02/03/2023] Open
Abstract
Newly synthesized neurofilaments or protofilaments are incorporated into a highly stable stationary cytoskeleton network as they are transported along axons. Although the heavily phosphorylated carboxyl-terminal tail domains of the heavy and medium neurofilament (NF) subunits have been proposed to contribute to this process and particularly to stability of this structure, their function is still obscure. Here we show in NF-H/M tail deletion [NF-(H/M)(tailΔ)] mice that the deletion of both of these domains selectively lowers NF levels 3-6 fold along optic axons without altering either rates of subunit synthesis or the rate of slow axonal transport of NF. Pulse labeling studies carried out over 90 days revealed a significantly faster rate of disappearance of NF from the stationary NF network of optic axons in NF-(H/M)(tailΔ) mice. Faster NF disappearance was accompanied by elevated levels of NF-L proteolytic fragments in NF-(H/M)(tailΔ) axons. We conclude that NF-H and NF-M C-terminal domains do not normally regulate NF transport rates as previously proposed, but instead increase the proteolytic resistance of NF, thereby stabilizing the stationary neurofilament cytoskeleton along axons.
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Affiliation(s)
- Mala V Rao
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York, United States of America.
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Peripherin is a subunit of peripheral nerve neurofilaments: implications for differential vulnerability of CNS and peripheral nervous system axons. J Neurosci 2012; 32:8501-8. [PMID: 22723690 DOI: 10.1523/jneurosci.1081-12.2012] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Peripherin, a neuronal intermediate filament protein implicated in neurodegenerative disease, coexists with the neurofilament triplet proteins [neurofilament light (NFL), medium (NFM), and heavy (NFH) chain] but has an unknown function. The earlier peak expression of peripherin than the triplet during brain development and its ability to form homopolymers, unlike the triplet, which are obligate heteropolymers, have supported a widely held view that peripherin and neurofilament triplets form separate filament systems. However, here, we demonstrate that, despite a postnatal decline in expression, peripherin is as abundant as the triplet in the adult PNS and exists in a relatively fixed stoichiometry with these subunits. Peripherin exhibits a distribution pattern identical to those of triplet proteins in sciatic axons and colocalizes with NFL on single neurofilaments by immunogold electron microscopy. Peripherin also coassembles into a single network of filaments containing NFL, NFM, and NFH with and without α-internexin in quadruple- or quintuple-transfected SW13vim(-) cells. Genetically deleting NFL in mice dramatically reduces peripherin content in sciatic axons. Moreover, peripherin mutations has been shown to disrupt the neurofilament network in transfected SW13vim(-) cells. These data show that peripherin and the neurofilament proteins are functionally interdependent. The results strongly support the view that, rather than forming an independent structure, peripherin is a subunit of neurofilaments in the adult PNS. Our findings provide a basis for its close relationship with neurofilaments in PNS diseases associated with neurofilament accumulation.
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Yuan A, Sasaki T, Kumar A, Peterhoff CM, Rao MV, Liem RK, Julien JP, Nixon RA. Peripherin is a subunit of peripheral nerve neurofilaments: implications for differential vulnerability of CNS and peripheral nervous system axons. J Neurosci 2012. [PMID: 22723690 DOI: 10.1523/jneurosci.1081-12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023] Open
Abstract
Peripherin, a neuronal intermediate filament protein implicated in neurodegenerative disease, coexists with the neurofilament triplet proteins [neurofilament light (NFL), medium (NFM), and heavy (NFH) chain] but has an unknown function. The earlier peak expression of peripherin than the triplet during brain development and its ability to form homopolymers, unlike the triplet, which are obligate heteropolymers, have supported a widely held view that peripherin and neurofilament triplets form separate filament systems. However, here, we demonstrate that, despite a postnatal decline in expression, peripherin is as abundant as the triplet in the adult PNS and exists in a relatively fixed stoichiometry with these subunits. Peripherin exhibits a distribution pattern identical to those of triplet proteins in sciatic axons and colocalizes with NFL on single neurofilaments by immunogold electron microscopy. Peripherin also coassembles into a single network of filaments containing NFL, NFM, and NFH with and without α-internexin in quadruple- or quintuple-transfected SW13vim(-) cells. Genetically deleting NFL in mice dramatically reduces peripherin content in sciatic axons. Moreover, peripherin mutations has been shown to disrupt the neurofilament network in transfected SW13vim(-) cells. These data show that peripherin and the neurofilament proteins are functionally interdependent. The results strongly support the view that, rather than forming an independent structure, peripherin is a subunit of neurofilaments in the adult PNS. Our findings provide a basis for its close relationship with neurofilaments in PNS diseases associated with neurofilament accumulation.
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Affiliation(s)
- Aidong Yuan
- Center for Dementia Research, Nathan Kline Institute, Orangeburg, New York 10962, USA.
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40
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Gentil BJ, Cooper L. Molecular basis of axonal dysfunction and traffic impairments in CMT. Brain Res Bull 2012; 88:444-53. [PMID: 22595495 DOI: 10.1016/j.brainresbull.2012.05.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 05/01/2012] [Accepted: 05/04/2012] [Indexed: 12/17/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) is one of the most common inherited neurological disorders. It comprises a group of diseases caused by mutations in genes involved in Schwann cells homeostasis and neuronal function that affect the peripheral nerves. So far mutations in more than 33 genes have been identified causing either the demyelinating form (CMT1) or the axonal form (CMT2). Genes involving a large variety of unrelated functions may lead to the same phenotype when mutated. Our review will focus on the common link between genes causing axonal phenotypes like MFN2, KIF1B, DYNC1H1, Rab7, TRPV4, ARSs, NEFL, HSPB1, MPZ, and HSPB8. While KIF1B and DYNC1H1, two genes coding for molecular motors, are directly linked to axonal transport, the involvement of the other CMT2-causing genes in this function is less obvious. However, the last years have seen a growing list of evidence demonstrating that intracellular trafficking and mitochondrial dynamics might be dysfunctional in CMT2, and these mechanisms might present a common link between dissimilar CMT2-causing genes. The involvement of impaired transport in the pathogenesis of other rare neurological diseases or recessive CMT2 is also discussed.
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Affiliation(s)
- Benoit J Gentil
- Department of Neurology/Neurosurgery and Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4 Canada.
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Baucum AJ, Strack S, Colbran RJ. Age-dependent targeting of protein phosphatase 1 to Ca2+/calmodulin-dependent protein kinase II by spinophilin in mouse striatum. PLoS One 2012; 7:e31554. [PMID: 22348105 PMCID: PMC3278457 DOI: 10.1371/journal.pone.0031554] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Accepted: 01/11/2012] [Indexed: 12/02/2022] Open
Abstract
Mechanisms underlying age-dependent changes of dendritic spines on striatal medium spiny neurons are poorly understood. Spinophilin is an F-actin- and protein phosphatase 1 (PP1)-binding protein that targets PP1 to multiple downstream effectors to modulate dendritic spine morphology and function. We found that calcium/calmodulin-dependent protein kinase II (CaMKII) directly and indirectly associates with N- and C-terminal domains of spinophilin, but F-actin can displace CaMKII from the N-terminal domain. Spinophilin co-localizes PP1 with CaMKII on the F-actin cytoskeleton in heterologous cells, and spinophilin co-localizes with synaptic CaMKII in neuronal cultures. Thr286 autophosphorylation enhances the binding of CaMKII to spinophilin in vitro and in vivo. Although there is no change in total levels of Thr286 autophosphorylation, maturation from postnatal day 21 into adulthood robustly enhances the levels of CaMKII that co-immunoprecipitate with spinophilin from mouse striatal extracts. Moreover, N- and C-terminal domain fragments of spinophilin bind more CaMKII from adult vs. postnatal day 21 striatal lysates. Total levels of other proteins that interact with C-terminal domains of spinophilin decrease during maturation, perhaps reducing competition for CaMKII binding to the C-terminal domain. In contrast, total levels of α-internexin and binding of α-internexin to the spinophilin N-terminal domain increases with maturation, perhaps bridging an indirect interaction with CaMKII. Moreover, there is an increase in the levels of myosin Va, α-internexin, spinophilin, and PP1 in striatal CaMKII immune complexes isolated from adult and aged mice compared to those from postnatal day 21. These changes in spinophilin/CaMKII interactomes may contribute to changes in striatal dendritic spine density, morphology, and function during normal postnatal maturation and aging.
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Affiliation(s)
- Anthony J Baucum
- Department of Molecular Physiology and Biophysics, Vanderbilt-Kennedy Center, Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America.
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Gentil BJ, Minotti S, Beange M, Baloh RH, Julien JP, Durham HD. Normal role of the low-molecular-weight neurofilament protein in mitochondrial dynamics and disruption in Charcot-Marie-Tooth disease. FASEB J 2011; 26:1194-203. [PMID: 22155564 DOI: 10.1096/fj.11-196345] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Intermediate filaments serve important structural roles, but other cellular functions are increasingly recognized. This study demonstrated normal function of the low-molecular-weight neurofilament protein (NFL) in mitochondrial dynamics and disruption in Charcot-Marie-Tooth disease (CMT) due to mutations in the Nefl gene. In motor neurons of spinal cord cultured from Nefl-knockout mice, mitochondrial length and the rate of fusion were decreased concomitant with increased motility. These parameters were normalized after expression of NFL(wt) on the Nefl(-/-) background, but not by overexpression of the profusion protein, mitofusin 2 (MFN2). The effects of CMT-causing NFL mutants bore similarities to and differences from Nefl knockout. In the early phase of toxicity before disruption of the neurofilament network, NFL(Q333P) and NFL(P8R) integrated into neurofilaments and had effects on mitochondria similar to those with Nefl knockout. The reduction of fusion rate by NFL(Q333P) was partly due to interference with the function of the profusion protein MFN2, which is mutated in CMT2A, functionally linking these forms of CMT. In the later phase of toxicity, mitochondria essentially stopped moving in neurons expressing NFL mutants, probably a consequence of cytoskeletal disruption. Overall, the data point to important functions of neurofilaments in mitochondrial dynamics as well as primary involvement in CMT2E/1F.
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Affiliation(s)
- Benoit J Gentil
- Montreal Neurological Institute, 3801 University St., Room 649, Montreal, QC, Canada H3A 2B4.
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Yang DS, Lee JH, Vinod KY, Stavrides P, Amin ND, Pant HC, Nixon RA. Declining phosphatases underlie aging-related hyperphosphorylation of neurofilaments. Neurobiol Aging 2009; 32:2016-29. [PMID: 20031277 DOI: 10.1016/j.neurobiolaging.2009.12.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 11/24/2009] [Accepted: 12/02/2009] [Indexed: 01/03/2023]
Abstract
Cytoskeletal protein phosphorylation is frequently altered in neuropathologic states but little is known about changes during normal aging. Here we report that declining protein phosphatase activity, rather than activation of kinases, underlies aging-related neurofilament hyperphosphorylation. Purified PP2A or PP2B dephosphorylated the heavy neurofilament (NFH) subunit or its extensively phorphorylated carboxyl-terminal domain in vitro. In cultured primary hippocampal neurons, inhibiting either phosphatase induced NFH phosphorylation without activating known neurofilament kinases. Neurofilament phosphorylation in the mouse CNS, as reflected by levels of the RT-97 phosphoepitope associated with late axon maturation, more than doubled during the 12-month period after NFH expression plateaued at p21. This was accompanied by declines in levels and activity of PP2A but not PP2B, and no rise in activities of neurofilament kinases (Erk1,2, cdk5 and JNK1,2). Inhibiting PP2A in mice in vivo restored brain RT-97 to levels seen in young mice. Declining PP2A activity, therefore, can account for rising neurofilament phosphorylation in maturing brain, potentially compounding similar changes associated with adult-onset neurodegenerative diseases.
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