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van Asperen JV, Kotaich F, Caillol D, Bomont P. Neurofilaments: Novel findings and future challenges. Curr Opin Cell Biol 2024; 87:102326. [PMID: 38401181 DOI: 10.1016/j.ceb.2024.102326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 01/07/2024] [Indexed: 02/26/2024]
Abstract
Neurofilaments (NFs) are abundant cytoskeletal proteins that emerge as a critical hub for cell signalling within neurons. As we start to uncover essential roles of NFs in regulating microtubule and organelle dynamics, nerve conduction and neurotransmission, novel discoveries are expected to arise in genetics, with NFs identified as causal genes for various neurodegenerative diseases. This review will discuss how the latest advances in fundamental and translational research illuminate our understanding of NF biology, particularly their assembly, organisation, transport and degradation. We will emphasise the notion that filaments are not one entity and that future challenges will be to apprehend their diverse composition and structural heterogeneity and to scrutinize how this regulates signalling, sustains neuronal physiology and drives pathophysiology in disease.
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Affiliation(s)
- Jessy V van Asperen
- ERC Team, NeuroMyoGene Insitute, INMG-PGNM, Inserm U1315, CNRS UMR5261, University of Lyon 1, Lyon, France
| | - Farah Kotaich
- ERC Team, NeuroMyoGene Insitute, INMG-PGNM, Inserm U1315, CNRS UMR5261, University of Lyon 1, Lyon, France
| | - Damien Caillol
- ERC Team, NeuroMyoGene Insitute, INMG-PGNM, Inserm U1315, CNRS UMR5261, University of Lyon 1, Lyon, France
| | - Pascale Bomont
- ERC Team, NeuroMyoGene Insitute, INMG-PGNM, Inserm U1315, CNRS UMR5261, University of Lyon 1, Lyon, France.
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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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Chen X, Ma L, Gan K, Pan X, Chen S. Phosphorylated proteomics-based analysis of the effects of semaglutide on hippocampi of high-fat diet-induced-obese mice. Diabetol Metab Syndr 2023; 15:63. [PMID: 36998046 PMCID: PMC10064769 DOI: 10.1186/s13098-023-01023-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2023] [Accepted: 03/08/2023] [Indexed: 04/01/2023] Open
Abstract
The aim of this paper was to investigate the effects of semaglutide on phosphorylated protein expression, and its neuroprotective mechanism in hippocampi of high-fat-diet-induced obese mice. In total, 16 obese mice were randomly divided into model group (H group) and semaglutide group (S group), with 8 mice in each group. In addition, a control group (C group) was set up comprising 8 C57BL/6J male normal mice. The Morris water maze assay was conducted to detect cognitive function changes in the mice, and to observe and compare body weight and expression levels of serological indicators between groups after the intervention. Phosphorylated proteomic analysis was performed to detect the hippocampal protein profile in mice. Proteins up-regulated twofold or down-regulated 0.5-fold in each group and with t-test p < 0.05 were defined as differentially phosphorylated proteins and were analyzed bioinformatically. The results showed that the high-fat diet-induced obese mice had reduced body weight, improved oxidative stress indexes, significantly increased the percentage of water maze trips and the number of platform crossings, and significantly shortened the water maze platform latency after semaglutide intervention. The phosphorylated proteomics results identified that 44 overlapping proteins among the three experimental groups. Most of the phosphorylated proteins identified were closely associated with pathways of neurodegeneration-multiple diseases. In addition, we identified Huntington, Neurofilament light chain, Neurofilament heavy chain as drug targets. This study demonstrates for the first time that semaglutide exerts neuroprotective effects by reducing HTT Ser1843, NEFH Ser 661 phosphorylation and increasing NEFL Ser 473 phosphorylation in hippocampal tissue of obese mice.
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Affiliation(s)
- Xiaoyi Chen
- Graduate School of Hebei North University, Zhangjiakou, China
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China
| | - Liang Ma
- Department of Neurology, Hebei General Hospital, Shijiazhuang, China
| | - Kexin Gan
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China
| | - Xiaoyu Pan
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China
| | - Shuchun Chen
- Department of Endocrinology, Hebei General Hospital, Shijiazhuang, China.
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Stone EJ, Kolb SJ, Brown A. A review and analysis of the clinical literature on Charcot-Marie-Tooth disease caused by mutations in neurofilament protein L. Cytoskeleton (Hoboken) 2021; 78:97-110. [PMID: 33993654 PMCID: PMC10174713 DOI: 10.1002/cm.21676] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 01/22/2023]
Abstract
Charcot-Marie-Tooth disease (CMT) is one of the most common inherited neurological disorders and can be caused by mutations in over 100 different genes. One of the causative genes is NEFL on chromosome 8 which encodes neurofilament light protein (NEFL), one of five proteins that co-assemble to form neurofilaments. At least 34 different CMT-causing mutations in NEFL have been reported which span the head, rod, and tail domains of the protein. The majority of these mutations are inherited dominantly, but some are inherited recessively. The resulting disease is classified variably in clinical reports based on electrodiagnostic studies as either axonal (type 2; CMT2E), demyelinating (type 1; CMT1F), or a form intermediate between the two (dominant intermediate; DI-CMTG). In this article, we first present a brief introduction to CMT and neurofilaments. We then collate and analyze the data from the clinical literature on the disease classification, age of onset and electrodiagnostic test results for the various mutations. We find that mutations in the head, rod, and tail domains can all cause disease with early onset and profound neurological impairment, with a trend toward greater severity for head domain mutations. We also find that the disease classification does not correlate with specific mutation or domain. In fact, different individuals with the same mutation can be classified as having axonal, demyelinating, or dominant intermediate forms of the disease. This suggests that the classification of the disease as CMT2E, CMT1F or DI-CMTG has more to do with variable disease presentation than to differences in the underlying disease mechanism, which is most likely primarily axonal in all cases.
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Affiliation(s)
- Elizabeth J Stone
- Department of Neuroscience, Ohio State University, Columbus, Ohio, USA.,Neuroscience Graduate Program, Ohio State University, Columbus, Ohio, USA
| | - Stephen J Kolb
- Department of Neurology, Ohio State University, Columbus, Ohio, USA.,Department of Biological Chemistry and Pharmacology, Ohio State University, Columbus, Ohio, USA
| | - Anthony Brown
- Department of Neuroscience, Ohio State University, Columbus, Ohio, USA
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Moss KR, Bopp TS, Johnson AE, Höke A. New evidence for secondary axonal degeneration in demyelinating neuropathies. Neurosci Lett 2021; 744:135595. [PMID: 33359733 PMCID: PMC7852893 DOI: 10.1016/j.neulet.2020.135595] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 10/31/2020] [Accepted: 12/19/2020] [Indexed: 12/28/2022]
Abstract
Development of peripheral nervous system (PNS) myelin involves a coordinated series of events between growing axons and the Schwann cell (SC) progenitors that will eventually ensheath them. Myelin sheaths have evolved out of necessity to maintain rapid impulse propagation while accounting for body space constraints. However, myelinating SCs perform additional critical functions that are required to preserve axonal integrity including mitigating energy consumption by establishing the nodal architecture, regulating axon caliber by organizing axonal cytoskeleton networks, providing trophic and potentially metabolic support, possibly supplying genetic translation materials and protecting axons from toxic insults. The intermediate steps between the loss of these functions and the initiation of axon degeneration are unknown but the importance of these processes provides insightful clues. Prevalent demyelinating diseases of the PNS include the inherited neuropathies Charcot-Marie-Tooth Disease, Type 1 (CMT1) and Hereditary Neuropathy with Liability to Pressure Palsies (HNPP) and the inflammatory diseases Acute Inflammatory Demyelinating Polyneuropathy (AIDP) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP). Secondary axon degeneration is a common feature of demyelinating neuropathies and this process is often correlated with clinical deficits and long-lasting disability in patients. There is abundant electrophysiological and histological evidence for secondary axon degeneration in patients and rodent models of PNS demyelinating diseases. Fully understanding the involvement of secondary axon degeneration in these diseases is essential for expanding our knowledge of disease pathogenesis and prognosis, which will be essential for developing novel therapeutic strategies.
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Affiliation(s)
- Kathryn R Moss
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Taylor S Bopp
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Anna E Johnson
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Ahmet Höke
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States.
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Stone EJ, Uchida A, Brown A. Charcot-Marie-Tooth disease Type 2E/1F mutant neurofilament proteins assemble into neurofilaments. Cytoskeleton (Hoboken) 2019; 76:423-439. [PMID: 31574566 DOI: 10.1002/cm.21566] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/30/2019] [Accepted: 09/13/2019] [Indexed: 11/12/2022]
Abstract
Charcot-Marie-Tooth disease Type 2E/1F (CMT2E/1F) is a peripheral neuropathy caused by mutations in neurofilament protein L (NFL), which is one of five neurofilament subunit proteins that co-assemble to form neurofilaments in vivo. Prior studies on cultured cells have shown that CMT2E/1F mutations disrupt neurofilament assembly and lead to protein aggregation, suggesting a possible disease mechanism. However, electron microscopy of axons in peripheral nerve biopsies from patients has revealed accumulations of neurofilament polymers of normal appearance and no evidence of protein aggregates. To reconcile these observations, we reexamined the assembly of seven CMT2E/1F NFL mutants in cultured cells. None of the mutants assembled into homopolymers in SW13vim- cells, but P8R, P22S, L268/269P, and P440/441L mutant NFL assembled into heteropolymers in the presence of neurofilament protein M (NFM) alone, and N98S, Q332/333P, and E396/397K mutant NFL assembled in the presence of NFM and peripherin. P8R, P22S, N98S, L268/269P, E396/397K, and P440/441L mutant NFL co-assembled into neurofilaments with endogenous NFL, NFM, and α-internexin in cultured neurons, although the N98S and E396/397K mutants showed reduced filament incorporation, and the Q332/333P mutant showed limited incorporation. We conclude that all the mutants are capable of assembling into neurofilaments, but for some of the mutants this was dependent on the identity of the other neurofilament proteins available for co-assembly, and most likely also their relative expression level. Thus, caution should be exercised when drawing conclusions about the assembly capacity of CMT2E/1F mutants based on transient transfections in cultured cells.
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Affiliation(s)
- Elizabeth J Stone
- Department of Neuroscience, Ohio State University, Columbus, Ohio.,Neuroscience Graduate Program, Ohio State University, Columbus, Ohio
| | - Atsuko Uchida
- Department of Neuroscience, Ohio State University, Columbus, Ohio
| | - Anthony Brown
- Department of Neuroscience, Ohio State University, Columbus, Ohio
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Yang FR, Chen J, Yi H, Peng LY, Hu XL, Guo QL. MicroRNA-7a ameliorates neuropathic pain in a rat model of spinal nerve ligation via the neurofilament light polypeptide-dependent signal transducer and activator of transcription signaling pathway. Mol Pain 2019; 15:1744806919842464. [PMID: 30987515 PMCID: PMC6537231 DOI: 10.1177/1744806919842464] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Neuropathic pain is a type of chronic pain induced by either central or
peripheral nerve injury. MicroRNAs have been recently linked to many diseases,
including neuropathic pain. However, the role of miR-7a in neuropathic pain
still remains elusive. Thus, we aim to investigate the effects of miR-7a on
neuropathic pain based on the spinal nerve ligation rat model. After
establishment of spinal nerve ligation rat models, rats were infected with
adeno-associated virus-neurofilament light polypeptide, adeno-associated
virus-miR-7a or treated with metformin. The paw withdrawal threshold and paw
withdrawal latency were assessed afterward, and the expression of miR-7a and
neurofilament light polypeptide as well as their interaction was determined.
Subsequently, miR-7a was overexpressed or silenced in dorsal root ganglion cells
to investigate the role of miR-7a in neuropathic pain. Furthermore, the
regulatory effect of neurofilament light polypeptide on neuropathic pain was
detected using plasmid overexpressing neurofilament light polypeptide. Spinal
nerve ligation rat model exhibited upregulation of neurofilament light
polypeptide but downregulation of miR-7a. In addition, neurofilament light
polypeptide accumulation or miR-7a inhibition decreased paw withdrawal threshold
and paw withdrawal latency. Then, neurofilament light polypeptide accumulation
or miR-7a inhibition was observed to increase the phosphorylation level of
signal transducer and activator of transcription. miR-7a was found to directly
target neurofilament light polypeptide and downregulate neurofilament light
polypeptide. In addition, inhibiting the signal transducer and activator of
transcription signaling pathway was also revealed to increase paw withdrawal
threshold and paw withdrawal latency. Collectively, our study demonstrated that
miR-7a ameliorated neuropathic pain via blocking the signal transducer and
activator of transcription signaling pathway by repressing neurofilament light
polypeptide. These findings, if taken further, can be of important clinical
significance in treating patients with neuropathic pain.
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Affiliation(s)
- Feng-Rui Yang
- 1 Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, P.R. China.,2 Department of Anesthesiology, the First Affiliated Hospital of University of South China, Hengyang, P.R. China
| | - Ji Chen
- 3 Department of Endocrinology, the First Affiliated Hospital of University of South China, Hengyang, P.R. China
| | - Han Yi
- 2 Department of Anesthesiology, the First Affiliated Hospital of University of South China, Hengyang, P.R. China
| | - Liang-Yu Peng
- 2 Department of Anesthesiology, the First Affiliated Hospital of University of South China, Hengyang, P.R. China
| | - Xiao-Ling Hu
- 2 Department of Anesthesiology, the First Affiliated Hospital of University of South China, Hengyang, P.R. China
| | - Qu-Lian Guo
- 1 Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha, P.R. China
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