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Gujar V, Pande RD, Hardas BM, Das S. Nerve Growth Factor Signaling Modulates the Expression of Glutaminase in Dorsal Root Ganglion Neurons during Peripheral Inflammation. Int J Mol Sci 2024; 25:6053. [PMID: 38892241 PMCID: PMC11172420 DOI: 10.3390/ijms25116053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/28/2024] [Accepted: 05/29/2024] [Indexed: 06/21/2024] Open
Abstract
Glutamate functions as the major excitatory neurotransmitter for primary sensory neurons and has a crucial role in sensitizing peripheral nociceptor terminals producing sensitization. Glutaminase (GLS) is the synthetic enzyme that converts glutamine to glutamate. GLS-immunoreactivity (-ir) and enzyme activity are elevated in dorsal root ganglion (DRG) neuronal cell bodies during chronic peripheral inflammation, but the mechanism for this GLS elevation is yet to be fully characterized. It has been well established that, after nerve growth factor (NGF) binds to its high-affinity receptor tropomyosin receptor kinase A (TrkA), a retrograde signaling endosome is formed. This endosome contains the late endosomal marker Rab7GTPase and is retrogradely transported via axons to the cell soma located in the DRG. This complex is responsible for regulating the transcription of several critical nociceptive genes. Here, we show that this retrograde NGF signaling mediates the expression of GLS in DRG neurons during the process of peripheral inflammation. We disrupted the normal NGF/TrkA signaling in adjuvant-induced arthritic (AIA) Sprague Dawley rats by the pharmacological inhibition of TrkA or blockade of Rab7GTPase, which significantly attenuated the expression of GLS in DRG cell bodies. The results indicate that NGF/TrkA signaling is crucial for the production of glutamate and has a vital role in the development of neurogenic inflammation. In addition, our pain behavioral data suggest that Rab7GTPase can be a potential target for attenuating peripheral inflammatory pain.
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Affiliation(s)
- Vikramsingh Gujar
- Department of Anatomy and Cell Biology, Oklahoma State University, Center for Health Sciences, Tulsa, OK 74107, USA
| | - Radhika D. Pande
- Department of Biochemistry and Microbiology, Oklahoma State University, Center for Health Sciences, Tulsa, OK 74107, USA; (R.D.P.); (S.D.)
| | - Bhalchandra M. Hardas
- Department of Electronics Engineering, Shri Ramdeobaba College of Engineering and Management, Nagpur 440013, India;
| | - Subhas Das
- Department of Biochemistry and Microbiology, Oklahoma State University, Center for Health Sciences, Tulsa, OK 74107, USA; (R.D.P.); (S.D.)
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2
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Newman LE, Weiser Novak S, Rojas GR, Tadepalle N, Schiavon CR, Grotjahn DA, Towers CG, Tremblay MÈ, Donnelly MP, Ghosh S, Medina M, Rocha S, Rodriguez-Enriquez R, Chevez JA, Lemersal I, Manor U, Shadel GS. Mitochondrial DNA replication stress triggers a pro-inflammatory endosomal pathway of nucleoid disposal. Nat Cell Biol 2024; 26:194-206. [PMID: 38332353 PMCID: PMC11026068 DOI: 10.1038/s41556-023-01343-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 12/20/2023] [Indexed: 02/10/2024]
Abstract
Mitochondrial DNA (mtDNA) encodes essential subunits of the oxidative phosphorylation system, but is also a major damage-associated molecular pattern (DAMP) that engages innate immune sensors when released into the cytoplasm, outside of cells or into circulation. As a DAMP, mtDNA not only contributes to anti-viral resistance, but also causes pathogenic inflammation in many disease contexts. Cells experiencing mtDNA stress caused by depletion of the mtDNA-packaging protein, transcription factor A, mitochondrial (TFAM) or during herpes simplex virus-1 infection exhibit elongated mitochondria, enlargement of nucleoids (mtDNA-protein complexes) and activation of cGAS-STING innate immune signalling via mtDNA released into the cytoplasm. However, the relationship among aberrant mitochondria and nucleoid dynamics, mtDNA release and cGAS-STING activation remains unclear. Here we show that, under a variety of mtDNA replication stress conditions and during herpes simplex virus-1 infection, enlarged nucleoids that remain bound to TFAM exit mitochondria. Enlarged nucleoids arise from mtDNA experiencing replication stress, which causes nucleoid clustering via a block in mitochondrial fission at a stage when endoplasmic reticulum actin polymerization would normally commence, defining a fission checkpoint that ensures mtDNA has completed replication and is competent for segregation into daughter mitochondria. Chronic engagement of this checkpoint results in enlarged nucleoids trafficking into early and then late endosomes for disposal. Endosomal rupture during transit through this endosomal pathway ultimately causes mtDNA-mediated cGAS-STING activation. Thus, we propose that replication-incompetent nucleoids are selectively eliminated by an adaptive mitochondria-endosomal quality control pathway that is prone to innate immune system activation, which might represent a therapeutic target to prevent mtDNA-mediated inflammation during viral infection and other pathogenic states.
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Affiliation(s)
- Laura E Newman
- Salk Institute for Biological Studies, La Jolla, CA, USA
| | | | - Gladys R Rojas
- Salk Institute for Biological Studies, La Jolla, CA, USA
| | | | | | | | | | | | - Matthew P Donnelly
- Salk Institute for Biological Studies, La Jolla, CA, USA
- Medical Scientist Training Program, University of California, San Diego, La Jolla, CA, USA
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
| | - Sagnika Ghosh
- Salk Institute for Biological Studies, La Jolla, CA, USA
| | | | - Sienna Rocha
- Salk Institute for Biological Studies, La Jolla, CA, USA
| | | | - Joshua A Chevez
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Ian Lemersal
- La Jolla Institute for Immunology, La Jolla, CA, USA
| | - Uri Manor
- Salk Institute for Biological Studies, La Jolla, CA, USA.
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA.
- Department of Cell & Developmental Biology, University of California, San Diego, La Jolla, CA, USA.
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3
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Wong YC, Jayaraj ND, Belton TB, Shum GC, Ball HE, Ren D, Tadenev ALD, Krainc D, Burgess RW, Menichella DM. Misregulation of mitochondria-lysosome contact dynamics in Charcot-Marie-Tooth Type 2B disease Rab7 mutant sensory peripheral neurons. Proc Natl Acad Sci U S A 2023; 120:e2313010120. [PMID: 37878717 PMCID: PMC10622892 DOI: 10.1073/pnas.2313010120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 09/12/2023] [Indexed: 10/27/2023] Open
Abstract
Inter-organelle contact sites between mitochondria and lysosomes mediate the crosstalk and bidirectional regulation of their dynamics in health and disease. However, mitochondria-lysosome contact sites and their misregulation have not been investigated in peripheral sensory neurons. Charcot-Marie-Tooth type 2B disease is an autosomal dominant axonal neuropathy affecting peripheral sensory neurons caused by mutations in the GTPase Rab7. Using live super-resolution and confocal time-lapse microscopy, we showed that mitochondria-lysosome contact sites dynamically form in the soma and axons of peripheral sensory neurons. Interestingly, Charcot-Marie-Tooth type 2B mutant Rab7 led to prolonged mitochondria-lysosome contact site tethering preferentially in the axons of peripheral sensory neurons, due to impaired Rab7 GTP hydrolysis-mediated contact site untethering. We further generated a Charcot-Marie-Tooth type 2B mutant Rab7 knock-in mouse model which exhibited prolonged axonal mitochondria-lysosome contact site tethering and defective downstream axonal mitochondrial dynamics due to impaired Rab7 GTP hydrolysis as well as fragmented mitochondria in the axon of the sciatic nerve. Importantly, mutant Rab7 mice further demonstrated preferential sensory behavioral abnormalities and neuropathy, highlighting an important role for mutant Rab7 in driving degeneration of peripheral sensory neurons. Together, this study identifies an important role for mitochondria-lysosome contact sites in the pathogenesis of peripheral neuropathy.
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Affiliation(s)
- Yvette C. Wong
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Nirupa D. Jayaraj
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Tayler B. Belton
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - George C. Shum
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Hannah E. Ball
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Dongjun Ren
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | | | - Dimitri Krainc
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Simpson Querrey Center for Neurogenetics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | | | - Daniela M. Menichella
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL60611
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4
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Mulligan RJ, Winckler B. Regulation of Endosomal Trafficking by Rab7 and Its Effectors in Neurons: Clues from Charcot-Marie-Tooth 2B Disease. Biomolecules 2023; 13:1399. [PMID: 37759799 PMCID: PMC10527268 DOI: 10.3390/biom13091399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 09/09/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Intracellular endosomal trafficking controls the balance between protein degradation and synthesis, i.e., proteostasis, but also many of the cellular signaling pathways that emanate from activated growth factor receptors after endocytosis. Endosomal trafficking, sorting, and motility are coordinated by the activity of small GTPases, including Rab proteins, whose function as molecular switches direct activity at endosomal membranes through effector proteins. Rab7 is particularly important in the coordination of the degradative functions of the pathway. Rab7 effectors control endosomal maturation and the properties of late endosomal and lysosomal compartments, such as coordination of recycling, motility, and fusion with downstream compartments. The spatiotemporal regulation of endosomal receptor trafficking is particularly challenging in neurons because of their enormous size, their distinct intracellular domains with unique requirements (dendrites vs. axons), and their long lifespans as postmitotic, differentiated cells. In Charcot-Marie-Tooth 2B disease (CMT2B), familial missense mutations in Rab7 cause alterations in GTPase cycling and trafficking, leading to an ulcero-mutilating peripheral neuropathy. The prevailing hypothesis to account for CMT2B pathologies is that CMT2B-associated Rab7 alleles alter endocytic trafficking of the neurotrophin NGF and its receptor TrkA and, thereby, disrupt normal trophic signaling in the peripheral nervous system, but other Rab7-dependent pathways are also impacted. Here, using TrkA as a prototypical endocytic cargo, we review physiologic Rab7 effector interactions and control in neurons. Since neurons are among the largest cells in the body, we place particular emphasis on the temporal and spatial regulation of endosomal sorting and trafficking in neuronal processes. We further discuss the current findings in CMT2B mutant Rab7 models, the impact of mutations on effector interactions or balance, and how this dysregulation may confer disease.
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Affiliation(s)
- Ryan J. Mulligan
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22903, USA
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA 22903, USA
| | - Bettina Winckler
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22903, USA
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5
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Abstract
Neurons are markedly compartmentalized, which makes them reliant on axonal transport to maintain their health. Axonal transport is important for anterograde delivery of newly synthesized macromolecules and organelles from the cell body to the synapse and for the retrograde delivery of signaling endosomes and autophagosomes for degradation. Dysregulation of axonal transport occurs early in neurodegenerative diseases and plays a key role in axonal degeneration. Here, we provide an overview of mechanisms for regulation of axonal transport; discuss how these mechanisms are disrupted in neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, Huntington's disease, hereditary spastic paraplegia, amyotrophic lateral sclerosis, and Charcot-Marie-Tooth disease; and discuss therapeutic approaches targeting axonal transport.
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6
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Pacifico P, Testa G, Amodeo R, Mainardi M, Tiberi A, Convertino D, Arevalo JC, Marchetti L, Costa M, Cattaneo A, Capsoni S. Human TrkAR649W mutation impairs nociception, sweating and cognitive abilities: a mouse model of HSAN IV. Hum Mol Genet 2023; 32:1380-1400. [PMID: 36537577 PMCID: PMC10077510 DOI: 10.1093/hmg/ddac295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/11/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022] Open
Abstract
A functional nerve growth factor NGF-Tropomyosin Receptor kinase A (TrkA) system is an essential requisite for the generation and maintenance of long-lasting thermal and mechanical hyperalgesia in adult mammals. Indeed, mutations in the gene encoding for TrkA are responsible for a rare condition, named Hereditary Sensory and Autonomic Neuropathy type IV (HSAN IV), characterized by the loss of response to noxious stimuli, anhidrosis and cognitive impairment. However, to date, there is no available mouse model to properly understand how the NGF-TrkA system can lead to pathological phenotypes that are distinctive of HSAN IV. Here, we report the generation of a knock-in mouse line carrying the HSAN IV TrkAR649W mutation. First, by in vitro biochemical and biophysical analyses, we show that the pathological R649W mutation leads to kinase-inactive TrkA also affecting its membrane dynamics and trafficking. In agreement with the HSAN IV human phenotype, TrkAR649W/m mice display a lower response to thermal and chemical noxious stimuli, correlating with reduced skin innervation, in addition to decreased sweating in comparison to TrkAh/m controls. Moreover, the R649W mutation decreases anxiety-like behavior and compromises cognitive abilities, by impairing spatial-working and social memory. Our results further uncover unexplored roles of TrkA in thermoregulation and sociability. In addition to accurately recapitulating the clinical manifestations of HSAN IV patients, our findings contribute to clarifying the involvement of the NGF-TrkA system in pain sensation.
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Affiliation(s)
- Paola Pacifico
- Bio@SNS Laboratory, Scuola Normale Superiore, Pisa 56124, Italy
| | - Giovanna Testa
- Bio@SNS Laboratory, Scuola Normale Superiore, Pisa 56124, Italy
| | - Rosy Amodeo
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa 56127, Italy
- NEST, Scuola Normale Superiore, Pisa 56127, Italy
| | - Marco Mainardi
- Bio@SNS Laboratory, Scuola Normale Superiore, Pisa 56124, Italy
- Neuroscience Institute, National Research Council (IN-CNR), Pisa 56124, Italy
| | - Alexia Tiberi
- Bio@SNS Laboratory, Scuola Normale Superiore, Pisa 56124, Italy
| | - Domenica Convertino
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa 56127, Italy
- NEST, Scuola Normale Superiore, Pisa 56127, Italy
| | - Juan Carlos Arevalo
- Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain
- Institute of Biomedical Research of Salamanca, Salamanca 37007, Spain
| | - Laura Marchetti
- Center for Nanotechnology Innovation @NEST, Istituto Italiano di Tecnologia, Pisa 56127, Italy
- Department of Pharmacy, University of Pisa, Pisa 56126, Italy
| | - Mario Costa
- Neuroscience Institute, National Research Council (IN-CNR), Pisa 56124, Italy
- Pisa Center for Research and Clinical Implementation Flash Radiotherapy (CPFR@CISUP), Pisa 56126, Italy
| | - Antonino Cattaneo
- Bio@SNS Laboratory, Scuola Normale Superiore, Pisa 56124, Italy
- Rita Levi-Montalcini European Brain Research Institute (EBRI), Rome 00161, Italy
| | - Simona Capsoni
- Bio@SNS Laboratory, Scuola Normale Superiore, Pisa 56124, Italy
- Department of Neuroscience and Rehabilitation, Institute of Physiology, University of Ferrara, Ferrara 44121, Italy
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7
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Krzystek TJ, White JA, Rathnayake R, Thurston L, Hoffmar-Glennon H, Li Y, Gunawardena S. HTT (huntingtin) and RAB7 co-migrate retrogradely on a signaling LAMP1-containing late endosome during axonal injury. Autophagy 2023; 19:1199-1220. [PMID: 36048753 PMCID: PMC10012955 DOI: 10.1080/15548627.2022.2119351] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 12/09/2022] Open
Abstract
ABBREVIATIONS Atg5: Autophagy-related 5; Atg8a: Autophagy-related 8a; AL: autolysosome; AP: autophagosome; BAF1: bafilomycin A1; BDNF: brain derived neurotrophic factor; BMP: bone morphogenetic protein; Cyt-c-p: Cytochrome c proximal; CQ: chloroquine; DCTN1: dynactin 1; Dhc: dynein heavy chain; EE: early endosome; DYNC1I1: dynein cytoplasmic 1 intermediate chain 1; HD: Huntington disease; HIP1/Hip1: huntingtin interacting protein 1; HTT/htt: huntingtin; iNeuron: iPSC-derived human neurons; IP: immunoprecipitation; Khc: kinesin heavy chain; KIF5C: kinesin family member 5C; LAMP1/Lamp1: lysosomal associated membrane protein 1; LE: late endosome; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAP3K12/DLK: mitogen-activated protein kinase kinase kinase 12; MAPK8/JNK/bsk: mitogen-activated protein kinase 8/basket; MAPK8IP3/JIP3: mitogen-activated protein kinase 8 interacting protein 3; NGF: nerve growth factor; NMJ: neuromuscular junction; NTRK1/TRKA: neurotrophic receptor tyrosine kinase 1; NRTK2/TRKB: neurotrophic receptor tyrosine kinase 2; nuf: nuclear fallout; PG: phagophore; PtdIns3P: phosphatidylinositol-3-phosphate; puc: puckered; ref(2)P: refractory to sigma P; Rilpl: Rab interacting lysosomal protein like; Rip11: Rab11 interacting protein; RTN1: reticulon 1; syd: sunday driver; SYP: synaptophysin; SYT1/Syt1: synaptotagmin 1; STX17/Syx17: syntaxin 17; tkv: thickveins; VF: vesicle fraction; wit: wishful thinking; wnd: wallenda.
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Affiliation(s)
- Thomas J. Krzystek
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, New York, USA
| | - Joseph A. White
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, New York, USA
| | - Rasika Rathnayake
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, New York, USA
| | - Layne Thurston
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, New York, USA
| | - Hayley Hoffmar-Glennon
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, New York, USA
| | - Yichen Li
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, New York, USA
| | - Shermali Gunawardena
- Department of Biological Sciences, The State University of New York at Buffalo, Buffalo, New York, USA
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8
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Lin S, Leitão ADG, Fang S, Gu Y, Barber S, Gilliard-Telefoni R, Castro A, Sung K, Shen R, Florio JB, Mante ML, Ding J, Spencer B, Masliah E, Rissman RA, Wu C. Overexpression of alpha synuclein disrupts APP and Endolysosomal axonal trafficking in a mouse model of synucleinopathy. Neurobiol Dis 2023; 178:106010. [PMID: 36702318 PMCID: PMC10754494 DOI: 10.1016/j.nbd.2023.106010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 01/18/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
Mutations or triplication of the alpha synuclein (ASYN) gene contribute to synucleinopathies including Parkinson's disease (PD), Dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). Recent evidence suggests that ASYN also plays an important role in amyloid-induced neurotoxicity, although the mechanism(s) remains unknown. One hypothesis is that accumulation of ASYN alters endolysosomal pathways to impact axonal trafficking and processing of the amyloid precursor protein (APP). To define an axonal function for ASYN, we used a transgenic mouse model of synucleinopathy that expresses a GFP-human ASYN (GFP-hASYN) transgene and an ASYN knockout (ASYN-/-) mouse model. Our results demonstrate that expression of GFP-hASYN in primary neurons derived from a transgenic mouse impaired axonal trafficking and processing of APP. In addition, axonal transport of BACE1, Rab5, Rab7, lysosomes and mitochondria were also reduced in these neurons. Interestingly, axonal transport of these organelles was also affected in ASYN-/- neurons, suggesting that ASYN plays an important role in maintaining normal axonal transport function. Therefore, selective impairment of trafficking and processing of APP by ASYN may act as a potential mechanism to induce pathological features of Alzheimer's disease (AD) in PD patients.
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Affiliation(s)
- Suzhen Lin
- Institute of Neurology, Ruijing Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China; Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - André D G Leitão
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Savannah Fang
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Yingli Gu
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Sophia Barber
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | | | - Alfredo Castro
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Kijung Sung
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Ruinan Shen
- Institute of Neurology, Ruijing Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China; Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Jazmin B Florio
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Michael L Mante
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Jianqing Ding
- Institute of Neurology, Ruijing Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Brian Spencer
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Eliezer Masliah
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Robert A Rissman
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA; VA San Diego Health System, La Jolla, CA, USA.
| | - Chengbiao Wu
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA.
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9
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Gu Y, Guerra F, Hu M, Pope A, Sung K, Yang W, Jetha S, Shoff TA, Gunatilake T, Dahlkamp O, Shi LZ, Manganelli F, Nolano M, Zhou Y, Ding J, Bucci C, Wu C. Mitochondria dysfunction in Charcot Marie Tooth 2B Peripheral Sensory Neuropathy. Commun Biol 2022; 5:717. [PMID: 35851620 PMCID: PMC9293960 DOI: 10.1038/s42003-022-03632-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 06/23/2022] [Indexed: 11/21/2022] Open
Abstract
Rab7 GTPase regulates mitochondrial morphology and function. Missense mutation(s) of Rab7 underlies the pathogenesis of Charcot Marie Tooth 2B (CMT2B) peripheral neuropathy. Herein, we investigate how mitochondrial morphology and function are impacted by the CMT2B associated Rab7V162M mutation. In contrast to recent studies of using heterologous overexpression systems, our results demonstrate significant mitochondrial fragmentation in both human CMT2B patient fibroblasts and CMT2B embryonic fibroblasts (MEFs). Primary cultured E18 dorsal root ganglion (DRG) sensory neurons also show mitochondrial fragmentation and altered axonal mitochondrial movement. In addition, we demonstrate that inhibitors to either the mitochondrial fission protein Drp1 or to the nucleotide binding to Rab7 normalize the mitochondrial deficits in both MEFs and E18 cultured DRG neurons. Our study reveals, for the first time, that expression of CMT2B Rab7 mutation at the physiological level enhances Drp1 activity to promote mitochondrial fission, potentially underlying selective vulnerability of peripheral sensory neurons in CMT2B pathogenesis. The Rab7V162M mutation associated with Charcot Marie Tooth 2B peripheral neuropathy causes mitochondrial fragmentation in patient-derived fibroblasts and primary cultured dorsal root ganglion sensory neurons from E18 mouse embryos.
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Affiliation(s)
- Yingli Gu
- Department of Neurosciences, University of California San Diego, La Jolla, 92093, CA, USA.,Department of Neurology, the Fourth Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Flora Guerra
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), Università del Salento, Via Provinciale Lecce-Monteroni n. 165, 73100, Lecce, Italy
| | - Mingzheng Hu
- Department of Neurosciences, University of California San Diego, La Jolla, 92093, CA, USA
| | - Alexander Pope
- Department of Neurosciences, University of California San Diego, La Jolla, 92093, CA, USA
| | - Kijung Sung
- Department of Neurosciences, University of California San Diego, La Jolla, 92093, CA, USA
| | - Wanlin Yang
- Department of Neurosciences, University of California San Diego, La Jolla, 92093, CA, USA.,Department of Neurology, Zhujiang Hospital of Southern Medical University Guangzhou, Guangzhou, 510280, Guangdong Sheng, China
| | - Simone Jetha
- Department of Neurosciences, University of California San Diego, La Jolla, 92093, CA, USA
| | - Thomas A Shoff
- Department of Neurosciences, University of California San Diego, La Jolla, 92093, CA, USA
| | - Tessanya Gunatilake
- Department of Neurosciences, University of California San Diego, La Jolla, 92093, CA, USA
| | - Owen Dahlkamp
- Department of Neurosciences, University of California San Diego, La Jolla, 92093, CA, USA
| | - Linda Zhixia Shi
- Department of Bioengineering, University of California San Diego, La Jolla, 92093, CA, USA
| | - Fiore Manganelli
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples "Federico II", Via Sergio Pansini 5, 80131, Naples, Italy
| | - Maria Nolano
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples "Federico II", Via Sergio Pansini 5, 80131, Naples, Italy
| | - Yue Zhou
- School of Biomedical Engineering, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai, 200030, China
| | - Jianqing Ding
- Institute of Neurology, Ruijin Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Cecilia Bucci
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), Università del Salento, Via Provinciale Lecce-Monteroni n. 165, 73100, Lecce, Italy.
| | - Chengbiao Wu
- Department of Neurosciences, University of California San Diego, La Jolla, 92093, CA, USA.
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10
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Liu Y, Lu Y, Tang Z, Cao Y, Huang D, Wu F, Zhang Y, Li C, Chen G, Wang Q. Single-particle fluorescence tracking combined with TrackMate assay reveals highly heterogeneous and discontinuous lysosomal transport in freely orientated axons. Biotechnol J 2022; 17:e2200006. [PMID: 35765726 DOI: 10.1002/biot.202200006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 06/11/2022] [Accepted: 06/22/2022] [Indexed: 11/12/2022]
Abstract
Axonal transport plays a significant role in the establishment of neuronal polarity, axon growth, and synapse formation during neuronal development. The axon of a naturally growing neuron is a highly complex and multifurcated structure with a large number of bends and branches. Nowadays, the study of dynamic axonal transport in morphologically complex neurons is greatly limited by the technological barrier. Here, a sparse gene transfection strategy was developed to locate fluorescent mCherry in the lysosome of primary neurons, thus enabling us to track the lysosome-based axonal transport with a single-particle resolution. Thereby, several axonal transport models were observed, including the forward or backward transport model, stop-and-go model, repeated back-and-forth transport model, and cross-branch transport model. Then, the accurate single-particle velocity quantification by TrackMate revealed a highly heterogeneous and discontinuous transportation process of lysosome-based axonal transport in freely orientated axons. And, multiple physical factors, such as the axonal structure and the size of particles, were disclosed to affect the velocity of particle transporting in freely orientated axons. The combined single-particle fluorescence tracking and TrackMate assay can be served as a facile tool for evaluating axonal transport in neuronal development and axonal transport-related diseases.
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Affiliation(s)
- Yongyang Liu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Yaxin Lu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Zhiyong Tang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China
| | - Yuheng Cao
- CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China.,School of Physical Science and Technology, ShanghaiTech University, Shanghai, China
| | - Dehua Huang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China
| | - Feng Wu
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China
| | - Yejun Zhang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China
| | - Chunyan Li
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Guangcun Chen
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Qiangbin Wang
- School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.,CAS Key Laboratory of Nano-Bio Interface, Suzhou Key Laboratory of Functional Molecular Imaging Technology, Division of Nanobiomedicine and i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China.,School of Physical Science and Technology, ShanghaiTech University, Shanghai, China.,College of Materials Sciences and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, China
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11
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Lischka A, Lassuthova P, Çakar A, Record CJ, Van Lent J, Baets J, Dohrn MF, Senderek J, Lampert A, Bennett DL, Wood JN, Timmerman V, Hornemann T, Auer-Grumbach M, Parman Y, Hübner CA, Elbracht M, Eggermann K, Geoffrey Woods C, Cox JJ, Reilly MM, Kurth I. Genetic pain loss disorders. Nat Rev Dis Primers 2022; 8:41. [PMID: 35710757 DOI: 10.1038/s41572-022-00365-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/10/2022] [Indexed: 01/05/2023]
Abstract
Genetic pain loss includes congenital insensitivity to pain (CIP), hereditary sensory neuropathies and, if autonomic nerves are involved, hereditary sensory and autonomic neuropathy (HSAN). This heterogeneous group of disorders highlights the essential role of nociception in protecting against tissue damage. Patients with genetic pain loss have recurrent injuries, burns and poorly healing wounds as disease hallmarks. CIP and HSAN are caused by pathogenic genetic variants in >20 genes that lead to developmental defects, neurodegeneration or altered neuronal excitability of peripheral damage-sensing neurons. These genetic variants lead to hyperactivity of sodium channels, disturbed haem metabolism, altered clathrin-mediated transport and impaired gene regulatory mechanisms affecting epigenetic marks, long non-coding RNAs and repetitive elements. Therapies for pain loss disorders are mainly symptomatic but the first targeted therapies are being tested. Conversely, chronic pain remains one of the greatest unresolved medical challenges, and the genes and mechanisms associated with pain loss offer new targets for analgesics. Given the progress that has been made, the coming years are promising both in terms of targeted treatments for pain loss disorders and the development of innovative pain medicines based on knowledge of these genetic diseases.
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Affiliation(s)
- Annette Lischka
- Institute of Human Genetics, Medical Faculty, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Petra Lassuthova
- Department of Paediatric Neurology, 2nd Faculty of Medicine, Charles University in Prague and Motol University Hospital, Prague, Czech Republic
| | - Arman Çakar
- Neuromuscular Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | - Christopher J Record
- Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Jonas Van Lent
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born Bunge, Antwerp, Belgium
| | - Jonathan Baets
- Laboratory of Neuromuscular Pathology, Institute Born Bunge, Antwerp, Belgium.,Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
| | - Maike F Dohrn
- Department of Neurology, Medical Faculty, Uniklinik RWTH Aachen University, Aachen, Germany.,Dr. John T. Macdonald Foundation, Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, FL, USA
| | - Jan Senderek
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University, Munich, Germany
| | - Angelika Lampert
- Institute of Physiology, Medical Faculty, Uniklinik RWTH Aachen University, Aachen, Germany
| | - David L Bennett
- Nuffield Department of Clinical Neuroscience, Oxford University, Oxford, UK
| | - John N Wood
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, UK
| | - Vincent Timmerman
- Peripheral Neuropathy Research Group, Department of Biomedical Sciences, University of Antwerp, Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born Bunge, Antwerp, Belgium
| | - Thorsten Hornemann
- Department of Clinical Chemistry, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Michaela Auer-Grumbach
- Department of Orthopedics and Trauma Surgery, Medical University of Vienna, Vienna, Austria
| | - Yesim Parman
- Neuromuscular Unit, Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Istanbul, Turkey
| | | | - Miriam Elbracht
- Institute of Human Genetics, Medical Faculty, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Katja Eggermann
- Institute of Human Genetics, Medical Faculty, Uniklinik RWTH Aachen University, Aachen, Germany
| | - C Geoffrey Woods
- Cambridge Institute for Medical Research, Keith Peters Building, Cambridge Biomedical Campus, Cambridge, UK
| | - James J Cox
- Molecular Nociception Group, Wolfson Institute for Biomedical Research, University College London, London, UK
| | - Mary M Reilly
- Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Ingo Kurth
- Institute of Human Genetics, Medical Faculty, Uniklinik RWTH Aachen University, Aachen, Germany.
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12
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Mitochondria-lysosome contact site dynamics and misregulation in neurodegenerative diseases. Trends Neurosci 2022; 45:312-322. [PMID: 35249745 PMCID: PMC8930467 DOI: 10.1016/j.tins.2022.01.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 01/11/2022] [Accepted: 01/26/2022] [Indexed: 02/06/2023]
Abstract
Neurons rely heavily on properly regulated mitochondrial and lysosomal homeostasis, with multiple neurodegenerative diseases linked to dysfunction in these two organelles. Interestingly, mitochondria-lysosome membrane contact sites have been identified as a key pathway mediating their crosstalk in neurons. Recent studies have further elucidated the regulation of mitochondria-lysosome contact dynamics via distinct tethering/untethering protein machinery. Moreover, this pathway has been shown to have additional functions in regulating organelle network dynamics and metabolite transfer between lysosomes and mitochondria. In this review, we highlight recent advances in the field of mitochondria-lysosome contact sites and their misregulation across multiple neurodegenerative disorders, which further underscore a potential role for this pathway in neuronal homeostasis and disease.
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13
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Nassal JP, Murphy FH, Toonen RF, Verhage M. Differential axonal trafficking of Neuropeptide Y-, LAMP1-, and RAB7-tagged organelles in vivo. eLife 2022; 11:81721. [PMID: 36459486 PMCID: PMC9718525 DOI: 10.7554/elife.81721] [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: 07/08/2022] [Accepted: 11/22/2022] [Indexed: 12/04/2022] Open
Abstract
Different organelles traveling through neurons exhibit distinct properties in vitro, but this has not been investigated in the intact mammalian brain. We established simultaneous dual color two-photon microscopy to visualize the trafficking of Neuropeptide Y (NPY)-, LAMP1-, and RAB7-tagged organelles in thalamocortical axons imaged in mouse cortex in vivo. This revealed that LAMP1- and RAB7-tagged organelles move significantly faster than NPY-tagged organelles in both anterograde and retrograde direction. NPY traveled more selectively in anterograde direction than LAMP1 and RAB7. By using a synapse marker and a calcium sensor, we further investigated the transport dynamics of NPY-tagged organelles. We found that these organelles slow down and pause at synapses. In contrast to previous in vitro studies, a significant increase of transport speed was observed after spontaneous activity and elevated calcium levels in vivo as well as electrically stimulated activity in acute brain slices. Together, we show a remarkable diversity in speeds and properties of three axonal organelle marker in vivo that differ from properties previously observed in vitro.
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Affiliation(s)
- Joris P Nassal
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU University Medical CenterAmsterdamNetherlands
| | - Fiona H Murphy
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU University Medical CenterAmsterdamNetherlands
| | - Ruud F Toonen
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU University Medical CenterAmsterdamNetherlands
| | - Matthijs Verhage
- Departments of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR), VU University Amsterdam and VU University Medical CenterAmsterdamNetherlands
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14
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Markworth R, Dambeck V, Steinbeck LM, Koufali A, Bues B, Dankovich TM, Wichmann C, Burk K. Tubular microdomains of Rab7-positive endosomes retrieve TrkA, a mechanism disrupted in Charcot-Marie-Tooth disease 2B. J Cell Sci 2021; 134:272650. [PMID: 34486665 DOI: 10.1242/jcs.258559] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 08/23/2021] [Indexed: 01/04/2023] Open
Abstract
Axonal survival and growth requires signalling from tropomyosin receptor kinases (Trks). To transmit their signals, receptor-ligand complexes are endocytosed and undergo retrograde trafficking to the soma, where downstream signalling occurs. Vesicles transporting neurotrophic receptors to the soma are reported to be Rab7-positive late endosomes and/or multivesicular bodies (MVBs), where receptors localize within so-called intraluminal vesicles (herein Rab7 corresponds to Rab7A unless specified otherwise). Therefore, one challenging question is how downstream signalling is possible given the insulating properties of intraluminal vesicles. In this study, we report that Rab7-positive endosomes and MVBs retrieve TrkA (also known as NTRK1) through tubular microdomains. Interestingly, this phenotype is absent for the EGF receptor. Furthermore, we found that endophilinA1, endophilinA2 and endophilinA3, together with WASH1 (also known as WASHC1), are involved in the tubulation process. In Charcot-Marie-Tooth disease 2B (CMT2B), a neuropathy of the peripheral nervous system, this tubulating mechanism is disrupted. In addition, the ability to tubulate correlates with the phosphorylation levels of TrkA as well as with neurite length in neuronal cultures from dorsal root ganglia. In all, we report a new retrieval mechanism of late Rab7-positive endosomes, which enables TrkA signalling and sheds new light onto how neurotrophic signalling is disrupted in CMT2B. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Ronja Markworth
- Department of Neurology, University Medical Center Göttingen, Robert Koch Straße 40, 37075 Göttingen, Germany.,European Neuroscience Institute, Grisebachstraße 5, 37077 Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Von-Siebold Straße 3A, 37075 Göttingen, Germany
| | - Vivian Dambeck
- Department of Neurology, University Medical Center Göttingen, Robert Koch Straße 40, 37075 Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Von-Siebold Straße 3A, 37075 Göttingen, Germany
| | - Lars Malte Steinbeck
- Department of Neurology, University Medical Center Göttingen, Robert Koch Straße 40, 37075 Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Von-Siebold Straße 3A, 37075 Göttingen, Germany
| | - Angeliki Koufali
- Department of Neurology, University Medical Center Göttingen, Robert Koch Straße 40, 37075 Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Von-Siebold Straße 3A, 37075 Göttingen, Germany
| | - Bastian Bues
- Department of Neurology, University Medical Center Göttingen, Robert Koch Straße 40, 37075 Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Von-Siebold Straße 3A, 37075 Göttingen, Germany
| | - Tal M Dankovich
- Institute for Neuro- and Sensory Physiology, Humboldtallee 23, 37073 Göttingen, Germany
| | - Carolin Wichmann
- Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Von-Siebold Straße 3A, 37075 Göttingen, Germany.,Molecular Architecture of Synapses Group, Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Collaborative Research Centers 889 'Cellular Mechanisms of Sensory Processing' and 1286 'Quantitative Synaptology', 37099 Göttingen, Germany
| | - Katja Burk
- Department of Neurology, University Medical Center Göttingen, Robert Koch Straße 40, 37075 Göttingen, Germany.,European Neuroscience Institute, Grisebachstraße 5, 37077 Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Von-Siebold Straße 3A, 37075 Göttingen, Germany
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15
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Markworth R, Bähr M, Burk K. Held Up in Traffic-Defects in the Trafficking Machinery in Charcot-Marie-Tooth Disease. Front Mol Neurosci 2021; 14:695294. [PMID: 34483837 PMCID: PMC8415527 DOI: 10.3389/fnmol.2021.695294] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/23/2021] [Indexed: 12/13/2022] Open
Abstract
Charcot-Marie-Tooth disease (CMT), also known as motor and sensory neuropathy, describes a clinically and genetically heterogenous group of disorders affecting the peripheral nervous system. CMT typically arises in early adulthood and is manifested by progressive loss of motor and sensory functions; however, the mechanisms leading to the pathogenesis are not fully understood. In this review, we discuss disrupted intracellular transport as a common denominator in the pathogenesis of different CMT subtypes. Intracellular transport via the endosomal system is essential for the delivery of lipids, proteins, and organelles bidirectionally to synapses and the soma. As neurons of the peripheral nervous system are amongst the longest neurons in the human body, they are particularly susceptible to damage of the intracellular transport system, leading to a loss in axonal integrity and neuronal death. Interestingly, defects in intracellular transport, both in neurons and Schwann cells, have been found to provoke disease. This review explains the mechanisms of trafficking and subsequently summarizes and discusses the latest findings on how defects in trafficking lead to CMT. A deeper understanding of intracellular trafficking defects in CMT will expand our understanding of CMT pathogenesis and will provide novel approaches for therapeutic treatments.
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Affiliation(s)
- Ronja Markworth
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany
| | - Mathias Bähr
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Katja Burk
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.,Center for Biostructural Imaging of Neurodegeneration, Göttingen, Germany
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16
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Martinez JL, Zammit MD, West NR, Christian BT, Bhattacharyya A. Basal Forebrain Cholinergic Neurons: Linking Down Syndrome and Alzheimer's Disease. Front Aging Neurosci 2021; 13:703876. [PMID: 34322015 PMCID: PMC8311593 DOI: 10.3389/fnagi.2021.703876] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/17/2021] [Indexed: 12/31/2022] Open
Abstract
Down syndrome (DS, trisomy 21) is characterized by intellectual impairment at birth and Alzheimer’s disease (AD) pathology in middle age. As individuals with DS age, their cognitive functions decline as they develop AD pathology. The susceptibility to degeneration of a subset of neurons, known as basal forebrain cholinergic neurons (BFCNs), in DS and AD is a critical link between cognitive impairment and neurodegeneration in both disorders. BFCNs are the primary source of cholinergic innervation to the cerebral cortex and hippocampus, as well as the amygdala. They play a critical role in the processing of information related to cognitive function and are directly engaged in regulating circuits of attention and memory throughout the lifespan. Given the importance of BFCNs in attention and memory, it is not surprising that these neurons contribute to dysfunctional neuronal circuitry in DS and are vulnerable in adults with DS and AD, where their degeneration leads to memory loss and disturbance in language. BFCNs are thus a relevant cell target for therapeutics for both DS and AD but, despite some success, efforts in this area have waned. There are gaps in our knowledge of BFCN vulnerability that preclude our ability to effectively design interventions. Here, we review the role of BFCN function and degeneration in AD and DS and identify under-studied aspects of BFCN biology. The current gaps in BFCN relevant imaging studies, therapeutics, and human models limit our insight into the mechanistic vulnerability of BFCNs in individuals with DS and AD.
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Affiliation(s)
- Jose L Martinez
- Cellular and Molecular Biology Graduate Program, University of Wisconsin, Madison, WI, United States.,Waisman Center, University of Wisconsin, Madison, WI, United States
| | - Matthew D Zammit
- Waisman Center, University of Wisconsin, Madison, WI, United States.,Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - Nicole R West
- Cellular and Molecular Biology Graduate Program, University of Wisconsin, Madison, WI, United States.,Waisman Center, University of Wisconsin, Madison, WI, United States
| | - Bradley T Christian
- Waisman Center, University of Wisconsin, Madison, WI, United States.,Department of Medical Physics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States.,Department of Psychiatry, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - Anita Bhattacharyya
- Waisman Center, University of Wisconsin, Madison, WI, United States.,Department of Cellular and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
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17
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Li L, Gruner K, Tourtellotte WG. Retrograde nerve growth factor signaling abnormalities in familial dysautonomia. J Clin Invest 2021; 130:2478-2487. [PMID: 32281946 DOI: 10.1172/jci130401] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 01/23/2020] [Indexed: 12/11/2022] Open
Abstract
Familial dysautonomia (FD) is the most prevalent form of hereditary sensory and autonomic neuropathy (HSAN). In FD, a germline mutation in the Elp1 gene leads to Elp1 protein decrease that causes sympathetic neuron death and sympathetic nervous system dysfunction (dysautonomia). Elp1 is best known as a scaffolding protein within the nuclear hetero-hexameric transcriptional Elongator protein complex, but how it functions in sympathetic neuron survival is very poorly understood. Here, we identified a cytoplasmic function for Elp1 in sympathetic neurons that was essential for retrograde nerve growth factor (NGF) signaling and neuron target tissue innervation and survival. Elp1 was found to bind to internalized TrkA receptors in an NGF-dependent manner, where it was essential for maintaining TrkA receptor phosphorylation (activation) by regulating PTPN6 (Shp1) phosphatase activity within the signaling complex. In the absence of Elp1, Shp1 was hyperactivated, leading to premature TrkA receptor dephosphorylation, which resulted in retrograde signaling failure and neuron death. Inhibiting Shp1 phosphatase activity in the absence of Elp1 rescued NGF-dependent retrograde signaling, and in an animal model of FD it rescued abnormal sympathetic target tissue innervation. These results suggest that regulation of retrograde NGF signaling in sympathetic neurons by Elp1 may explain sympathetic neuron loss and physiologic dysautonomia in patients with FD.
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Affiliation(s)
- Lin Li
- Department of Pathology and Laboratory Medicine
| | | | - Warren G Tourtellotte
- Department of Pathology and Laboratory Medicine.,Department of Neurology.,Department of Neurosurgery, and.,Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California, USA
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18
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Pensalfini A, Kim S, Subbanna S, Bleiwas C, Goulbourne CN, Stavrides PH, Jiang Y, Lee JH, Darji S, Pawlik M, Huo C, Peddy J, Berg MJ, Smiley JF, Basavarajappa BS, Nixon RA. Endosomal Dysfunction Induced by Directly Overactivating Rab5 Recapitulates Prodromal and Neurodegenerative Features of Alzheimer's Disease. Cell Rep 2020; 33:108420. [PMID: 33238112 DOI: 10.1016/j.celrep.2020.108420] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 06/05/2020] [Accepted: 11/02/2020] [Indexed: 12/11/2022] Open
Abstract
Neuronal endosomal dysfunction, the earliest known pathobiology specific to Alzheimer's disease (AD), is mediated by the aberrant activation of Rab5 triggered by APP-β secretase cleaved C-terminal fragment (APP-βCTF). To distinguish pathophysiological consequences specific to overactivated Rab5 itself, we activate Rab5 independently from APP-βCTF in the PA-Rab5 mouse model. We report that Rab5 overactivation alone recapitulates diverse prodromal and degenerative features of AD. Modest neuron-specific transgenic Rab5 expression inducing hyperactivation of Rab5 comparable to that in AD brain reproduces AD-related Rab5-endosomal enlargement and mistrafficking, hippocampal synaptic plasticity deficits via accelerated AMPAR endocytosis and dendritic spine loss, and tau hyperphosphorylation via activated glycogen synthase kinase-3β. Importantly, Rab5-mediated endosomal dysfunction induces progressive cholinergic neurodegeneration and impairs hippocampal-dependent memory. Aberrant neuronal Rab5-endosome signaling, therefore, drives a pathogenic cascade distinct from β-amyloid-related neurotoxicity, which includes prodromal and neurodegenerative features of AD, and suggests Rab5 overactivation as a potential therapeutic target.
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Affiliation(s)
- Anna Pensalfini
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA
| | - Seonil Kim
- Colorado State University, Department of Biomedical Sciences, Fort Collins, CO 80523, USA; Cellular and Molecular Biology Training Program, New York University Langone Health, New York, NY 10003, USA
| | - Shivakumar Subbanna
- Department of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Cynthia Bleiwas
- Department of Neurochemistry, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Chris N Goulbourne
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Philip H Stavrides
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Ying Jiang
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA
| | - Ju-Hyun Lee
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA
| | - Sandipkumar Darji
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Monika Pawlik
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Chunfeng Huo
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - James Peddy
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Martin J Berg
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - John F Smiley
- Department of Neurochemistry, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Balapal S Basavarajappa
- Department of Psychiatry, New York University Langone Health, New York, NY 10016, USA; Department of Analytical Psychopharmacology, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; New York State Psychiatric Institute, New York, NY 10032, USA; Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Ralph A Nixon
- Center for Dementia Research, Nathan Kline Institute for Psychiatric Research, 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 10003, USA; NYU Neuroscience Institute, New York, NY 10003, USA.
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19
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Pasterkamp RJ, Burk K. Axon guidance receptors: Endocytosis, trafficking and downstream signaling from endosomes. Prog Neurobiol 2020; 198:101916. [PMID: 32991957 DOI: 10.1016/j.pneurobio.2020.101916] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/06/2020] [Accepted: 09/21/2020] [Indexed: 02/06/2023]
Abstract
During the development of the nervous system, axons extend through complex environments. Growth cones at the axon tip allow axons to find and innervate their appropriate targets and form functional synapses. Axon pathfinding requires axons to respond to guidance signals and these cues need to be detected by specialized receptors followed by intracellular signal integration and translation. Several downstream signaling pathways have been identified for axon guidance receptors and it has become evident that these pathways are often initiated from intracellular vesicles called endosomes. Endosomes allow receptors to traffic intracellularly, re-locating receptors from one cellular region to another. The localization of axon guidance receptors to endosomal compartments is crucial for their function, signaling output and expression levels. For example, active receptors within endosomes can recruit downstream proteins to the endosomal membrane and facilitate signaling. Also, endosomal trafficking can re-locate receptors back to the plasma membrane to allow re-activation or mediate downregulation of receptor signaling via degradation. Accumulating evidence suggests that axon guidance receptors do not follow a pre-set default trafficking route but may change their localization within endosomes. This re-routing appears to be spatially and temporally regulated, either by expression of adaptor proteins or co-receptors. These findings shed light on how signaling in axon guidance is regulated and diversified - a mechanism which explains how a limited set of guidance cues can help to establish billions of neuronal connections. In this review, we summarize and discuss our current knowledge of axon guidance receptor trafficking and provide directions for future research.
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Affiliation(s)
- R J Pasterkamp
- Department of Translational Neuroscience, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, the Netherlands.
| | - K Burk
- Department of Neurology, University Medical Center Göttingen, 37075 Göttingen, Germany; Center for Biostructural Imaging of Neurodegeneration, 37075 Göttingen, Germany.
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20
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Giudetti AM, Guerra F, Longo S, Beli R, Romano R, Manganelli F, Nolano M, Mangini V, Santoro L, Bucci C. An altered lipid metabolism characterizes Charcot-Marie-Tooth type 2B peripheral neuropathy. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158805. [PMID: 32829064 DOI: 10.1016/j.bbalip.2020.158805] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 07/20/2020] [Accepted: 08/17/2020] [Indexed: 12/12/2022]
Abstract
Charcot-Marie Tooth type 2B (CMT2B) is a rare inherited peripheral neuropathy caused by five missense mutations in the RAB7A gene, which encodes a small GTPase of the RAB family. Currently, no cure is available for this disease. In this study, we approached the disease by comparing the lipid metabolism of CMT2B-derived fibroblasts to that of healthy controls. We found that CMT2B cells showed increased monounsaturated fatty acid level and increased expression of key enzymes of monounsaturated and polyunsaturated fatty acid synthesis. Moreover, in CMT2B cells a higher expression of acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), key enzymes of de novo fatty acid synthesis, with a concomitantly increased [1-14C]acetate incorporation into fatty acids, was observed. The expression of diacylglycerol acyltransferase 2, a rate-limiting enzyme in triacylglycerol synthesis, as well as triacylglycerol levels were increased in CMT2B compared to control cells. In addition, as RAB7A controls lipid droplet breakdown and lipid droplet dynamics have been linked to diseases, we analyzed these organelles and showed that in CMT2B cells there is a strong accumulation of lipid droplets compared to control cells, thus reinforcing our data on abnormal lipid metabolism in CMT2B. Furthermore, we demonstrated that ACC and FAS expression levels changed upon RAB7 silencing or overexpression in HeLa cells, thus suggesting that metabolic modifications observed in CMT2B-derived fibroblasts can be, at least in part, related to RAB7 mutations.
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Affiliation(s)
- Anna Maria Giudetti
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Monteroni n. 165, 73100 Lecce, Italy.
| | - Flora Guerra
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Monteroni n. 165, 73100 Lecce, Italy
| | - Serena Longo
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Monteroni n. 165, 73100 Lecce, Italy
| | - Raffaella Beli
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Monteroni n. 165, 73100 Lecce, Italy
| | - Roberta Romano
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Monteroni n. 165, 73100 Lecce, Italy
| | - Fiore Manganelli
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples "Federico II", Via Sergio Pansini 5, 80131, Naples, Italy
| | - Maria Nolano
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples "Federico II", Via Sergio Pansini 5, 80131, Naples, Italy; Istituti Clinici Scientifici Maugeri IRCCS, Department of Neurology of Telese Terme Institute, 82037 Telese Terme, Benevento, Italy
| | - Vincenzo Mangini
- Center for Biomolecular Nanotechnologies@UniLe, Istituto Italiano di Tecnologia, 73010 Arnesano (LE), Italy
| | - Lucio Santoro
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples "Federico II", Via Sergio Pansini 5, 80131, Naples, Italy
| | - Cecilia Bucci
- Department of Biological and Environmental Sciences and Technologies, University of Salento, Via Monteroni n. 165, 73100 Lecce, Italy.
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21
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Cai CZ, Yang C, Zhuang XX, Yuan NN, Wu MY, Tan JQ, Song JX, Cheung KH, Su H, Wang YT, Tang BS, Behrends C, Durairajan SSK, Yue Z, Li M, Lu JH. NRBF2 is a RAB7 effector required for autophagosome maturation and mediates the association of APP-CTFs with active form of RAB7 for degradation. Autophagy 2020; 17:1112-1130. [PMID: 32543313 DOI: 10.1080/15548627.2020.1760623] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
NRBF2 is a component of the class III phosphatidylinositol 3-kinase (PtdIns3K) complex. Our previous study has revealed its role in regulating ATG14-associated PtdIns3K activity for autophagosome initiation. In this study, we revealed an unknown mechanism by which NRBF2 modulates autophagosome maturation and APP-C-terminal fragment (CTF) degradation. Our data showed that NRBF2 localized at autolysosomes, and loss of NRBF2 impaired autophagosome maturation. Mechanistically, NRBF2 colocalizes with RAB7 and is required for generation of GTP-bound RAB7 by interacting with RAB7 GEF CCZ1-MON1A and maintaining the GEF activity. Specifically, NRBF2 regulates CCZ1-MON1A interaction with PI3KC3/VPS34 and CCZ1-associated PI3KC3 kinase activity, which are required for CCZ1-MON1A GEF activity. Finally, we showed that NRBF2 is involved in APP-CTF degradation and amyloid beta peptide production by maintaining the interaction between APP and the CCZ1-MON1A-RAB7 module to facilitate the maturation of APP-containing vesicles. Overall, our study revealed a pivotal role of NRBF2 as a new RAB7 effector in modulating autophagosome maturation, providing insight into the molecular mechanism of NRBF2-PtdIns3K in regulating RAB7 activity for macroautophagy/autophagy maturation and Alzheimer disease-associated protein degradation..Abbreviations: 3xTg AD, triple transgenic mouse for Alzheimer disease; Aβ, amyloid beta peptide; Aβ1-40, amyloid beta peptide 1-40; Aβ1-42, amyloid beta peptide 1-42; AD, Alzheimer disease; APP, amyloid beta precursor protein; APP-CTFs, APP C-terminal fragments; ATG, autophagy related; ATG5, autophagy related 5; ATG7, autophagy related 7; ATG14, autophagy related 14; CCD, coiled-coil domain; CCZ1, CCZ1 homolog, vacuolar protein trafficking and biogenesis associated; CHX, cycloheximide; CQ, chloroquine; DAPI, 4',6-diamidino-2-phenylindole; dCCD, delete CCD; dMIT, delete MIT; FYCO1, FYVE and coiled-coil domain autophagy adaptor 1; FYVE, Fab1, YGL023, Vps27, and EEA1; GAP, GTPase-activating protein; GDP, guanine diphosphate; GEF, guanine nucleotide exchange factor; GTP, guanine triphosphate; GTPase, guanosine triphosphatase; HOPS, homotypic fusion and vacuole protein sorting; ILVs, endosomal intralumenal vesicles; KD, knockdown; KO, knockout; LAMP1, lysosomal associated membrane protein 1; MAP1LC3/LC3, microtubule associated protein 1 light chain 3; MLVs, multilamellar vesicles; MON1A, MON1 homolog A, secretory trafficking associated; NRBF2, nuclear receptor binding factor 2; PtdIns3K, class III phosphatidylinositol 3-kinase; PtdIns3P, phosphatidylinositol-3-phosphate; RILP, Rab interacting lysosomal protein; SNARE, soluble N-ethylmaleimide-sensitive factor attachment protein receptor; SQSTM1/p62, sequestosome 1; UVRAG, UV radiation resistance associated; VPS, vacuolar protein sorting; WT, wild type.
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Affiliation(s)
- Cui-Zan Cai
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau SAR, China
| | - Chuanbin Yang
- Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Xu-Xu Zhuang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau SAR, China
| | - Ning-Ning Yuan
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau SAR, China
| | - Ming-Yue Wu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau SAR, China
| | - Jie-Qiong Tan
- Center for Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Ju-Xian Song
- Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China.,Medical College of Acupuncture-Moxibustion and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - King-Ho Cheung
- Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Huanxing Su
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau SAR, China
| | - Yi-Tao Wang
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau SAR, China
| | - Bei-Sha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Christian Behrends
- Munich Cluster for Systems Neurology (Synergy), Ludwig-Maximilians-Universität München, München, Germany
| | - Siva Sundara Kumar Durairajan
- Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China.,Division of Mycobiology and Neurodegenerative Disease Research, Department of Microbiology, School of Life Sciences, Central University of Tamil Nadu, Tiruvarur, India
| | - Zhenyu Yue
- Department of Neurology and Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Min Li
- Mr. And Mrs. Ko Chi Ming Centre for Parkinson's Disease Research, School of Chinese Medicine, Hong Kong Baptist University, Hong Kong SAR, China
| | - Jia-Hong Lu
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau SAR, China
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22
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Romano R, Rivellini C, De Luca M, Tonlorenzi R, Beli R, Manganelli F, Nolano M, Santoro L, Eskelinen EL, Previtali SC, Bucci C. Alteration of the late endocytic pathway in Charcot-Marie-Tooth type 2B disease. Cell Mol Life Sci 2020; 78:351-372. [PMID: 32280996 PMCID: PMC7867545 DOI: 10.1007/s00018-020-03510-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 03/18/2020] [Accepted: 03/24/2020] [Indexed: 12/18/2022]
Abstract
The small GTPase RAB7A regulates late stages of the endocytic pathway and plays specific roles in neurons, controlling neurotrophins trafficking and signaling, neurite outgrowth and neuronal migration. Mutations in the RAB7A gene cause the autosomal dominant Charcot–Marie–Tooth type 2B (CMT2B) disease, an axonal peripheral neuropathy. As several neurodegenerative diseases are caused by alterations of endocytosis, we investigated whether CMT2B-causing mutations correlate with changes in this process. To this purpose, we studied the endocytic pathway in skin fibroblasts from healthy and CMT2B individuals. We found higher expression of late endocytic proteins in CMT2B cells compared to control cells, as well as higher activity of cathepsins and higher receptor degradation activity. Consistently, we observed an increased number of lysosomes, accompanied by higher lysosomal degradative activity in CMT2B cells. Furthermore, we found increased migration and increased RAC1 and MMP-2 activation in CMT2B compared to control cells. To validate these data, we obtained sensory neurons from patient and control iPS cells, to confirm increased lysosomal protein expression and lysosomal activity in CMT2B-derived neurons. Altogether, these results demonstrate that in CMT2B patient-derived cells, the endocytic degradative pathway is altered, suggesting that higher lysosomal activity contributes to neurodegeneration occurring in CMT2B.
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Affiliation(s)
- Roberta Romano
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, Lecce, Italy
| | - Cristina Rivellini
- Institute of Experimental Neurology (INSPE), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Maria De Luca
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, Lecce, Italy
| | - Rossana Tonlorenzi
- Institute of Experimental Neurology (INSPE), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Raffaella Beli
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, Lecce, Italy
| | - Fiore Manganelli
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples "Federico II", Naples, Italy
| | - Maria Nolano
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples "Federico II", Naples, Italy
- Salvatore Maugeri Foundation, Institute of Telese Terme, Benevento, Italy
| | - Lucio Santoro
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples "Federico II", Naples, Italy
| | - Eeva-Liisa Eskelinen
- Institute of Biomedicine, University of Turku, Turku, Finland
- Molecular and Integrative Biosciences Research Programme, University of Helsinki, Helsinki, Finland
| | - Stefano C Previtali
- Institute of Experimental Neurology (INSPE), IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Cecilia Bucci
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, Lecce, Italy.
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23
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Abstract
The intracellular transport system in neurons is specialized to an extraordinary degree, enabling the delivery of critical cargo to sites in axons or dendrites that are far removed from the cell center. Vesicles formed in the cell body are actively transported by kinesin motors along axonal microtubules to presynaptic sites that can be located more than a meter away. Both growth factors and degradative vesicles carrying aged organelles or aggregated proteins take the opposite route, driven by dynein motors. Distance is not the only challenge; precise delivery of cargos to sites of need must also be accomplished. For example, localized delivery of presynaptic components to hundreds of thousands of "en passant" synapses distributed along the length of a single axon in some neuronal subtypes provides a layer of complexity that must be successfully navigated to maintain synaptic transmission. We review recent advances in the field of axonal transport, with a focus on conceptual developments, and highlight our growing quantitative understanding of neuronal trafficking and its role in maintaining the synaptic function that underlies higher cognitive processes such as learning and memory.
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Affiliation(s)
- Pedro Guedes-Dias
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.,Institute of Neuronal Cell Biology, Technische Universität München, 80802 Munich, Germany
| | - Erika L F Holzbaur
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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24
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Rossaert E, Van Den Bosch L. HDAC6 inhibitors: Translating genetic and molecular insights into a therapy for axonal CMT. Brain Res 2020; 1733:146692. [PMID: 32006555 DOI: 10.1016/j.brainres.2020.146692] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 01/24/2020] [Accepted: 01/27/2020] [Indexed: 12/25/2022]
Abstract
Histone deacetylase 6 (HDAC6) plays a central role in various processes that are key for neuronal survival. In this review, we summarize the current evidence related to disease pathways in the axonal form of Charcot-Marie-Tooth disease (CMT) and highlight the role of HDAC6 in these pathways. We hypothesize that HDAC6 might in fact actively contribute to the pathogenesis of certain forms of axonal CMT. HDAC6 plays a deacetylase activity-dependent, negative role in axonal transport and axonal regeneration, which are both processes implicated in axonal CMT. On the other hand, HDAC6 coordinates a protective response during elimination of toxic misfolded proteins, but this is mostly mediated independent of its deacetylase activity. The current mechanistic insights on these functions of HDAC6 in axonal CMT, along with the selective druggability against its deacetylase activity, make the targeting of HDAC6 particularly attractive. We elaborate on the preclinical studies that demonstrated beneficial effects of HDAC6 inhibitors in axonal CMT models and outline possible modes of action. Overall, this overview ultimately provides a rationale for the use of small-molecule HDAC6 inhibitors as a therapeutic strategy for this devastating disease.
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Affiliation(s)
- Elisabeth Rossaert
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), Leuven, Belgium; VIB - Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Ludo Van Den Bosch
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), Leuven, Belgium; VIB - Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.
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25
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26
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Rab GTPases: Switching to Human Diseases. Cells 2019; 8:cells8080909. [PMID: 31426400 PMCID: PMC6721686 DOI: 10.3390/cells8080909] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 08/13/2019] [Accepted: 08/14/2019] [Indexed: 02/07/2023] Open
Abstract
Rab proteins compose the largest family of small GTPases and control the different steps of intracellular membrane traffic. More recently, they have been shown to also regulate cell signaling, division, survival, and migration. The regulation of these processes generally occurs through recruitment of effectors and regulatory proteins, which control the association of Rab proteins to membranes and their activation state. Alterations in Rab proteins and their effectors are associated with multiple human diseases, including neurodegeneration, cancer, and infections. This review provides an overview of how the dysregulation of Rab-mediated functions and membrane trafficking contributes to these disorders. Understanding the altered dynamics of Rabs and intracellular transport defects might thus shed new light on potential therapeutic strategies.
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27
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Wong YC, Peng W, Krainc D. Lysosomal Regulation of Inter-mitochondrial Contact Fate and Motility in Charcot-Marie-Tooth Type 2. Dev Cell 2019; 50:339-354.e4. [PMID: 31231042 DOI: 10.1016/j.devcel.2019.05.033] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 02/25/2019] [Accepted: 05/16/2019] [Indexed: 10/26/2022]
Abstract
Properly regulated mitochondrial networks are essential for cellular function and implicated in multiple diseases. Mitochondria undergo fission and fusion events, but the dynamics and regulation of a third event of inter-mitochondrial contact formation remain unclear. Using super-resolution imaging, we demonstrate that inter-mitochondrial contacts frequently form and play a fundamental role in mitochondrial networks by restricting mitochondrial motility. Inter-mitochondrial contact untethering events are marked and regulated by mitochondria-lysosome contacts, which are modulated by RAB7 GTP hydrolysis. Moreover, inter-mitochondrial contact formation and untethering are further regulated by Mfn1/2 and Drp1 GTP hydrolysis, respectively. Surprisingly, endoplasmic reticulum tubules are also present at inter-mitochondrial contact untethering events, in addition to mitochondrial fission and fusion events. Importantly, we find that multiple Charcot-Marie-Tooth type 2 disease-linked mutations in Mfn2 (CMT2A), RAB7 (CMT2B), and TRPV4 (CMT2C) converge on prolonged inter-mitochondrial contacts and defective mitochondrial motility, highlighting a role for inter-mitochondrial contacts in mitochondrial network regulation and disease.
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Affiliation(s)
- Yvette C Wong
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Wesley Peng
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Dimitri Krainc
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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28
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A Model of Hereditary Sensory and Autonomic Neuropathy Type 1 Reveals a Role of Glycosphingolipids in Neuronal Polarity. J Neurosci 2019; 39:5816-5834. [PMID: 31138658 DOI: 10.1523/jneurosci.2541-18.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 05/15/2019] [Accepted: 05/19/2019] [Indexed: 12/14/2022] Open
Abstract
Hereditary sensory and autonomic neuropathy Type 1 (HSAN1) is a rare autosomal dominantly inherited neuropathy, clinically characterized by a loss of distal peripheral sensory and motoneuronal function. Mutations in subunits of serine palmitoyltransferase (SPT) have been linked to the majority of HSAN1 cases. SPTs catalyze the condensation of l-serine with palmitoyl-CoA, the first committed and rate-limiting step in de novo sphingolipid biosynthesis. Despite extensive investigation, the molecular pathogenesis of HSAN1 remains controversial. Here, we established a Caenorhabditis elegans (C. elegans) model of HSAN1 by generating a sptl-1(c363g) mutation, encoding SPTL-1(C121W) and equivalent to human SPTLC1C133W, at the C. elegans genomic locus through CRISPR. The sptl-1(c363g) homozygous mutants exhibited the same larval lethality and epithelial polarity defect as observed in sptl-1(RNAi) animals, suggesting a loss-of-function effect of the SPTL-1(C121W) mutation. sptl-1(c363g)/+ heterozygous mutants displayed sensory dysfunction with concomitant neuronal morphology and axon-dendrite polarity defects, demonstrating that the C. elegans model recapitulates characteristics of the human disease. sptl-1(c363g)-derived neuronal defects were copied in animals with defective sphingolipid biosynthetic enzymes downstream of SPTL-1, including ceramide glucosyltransferases, suggesting that SPTLC1C133W contributes to the HSAN1 pathogenesis by limiting the production of complex sphingolipids, including glucosylceramide. Overexpression of SPTL-1(C121W) led to similar epithelial and neuronal defects and to reduced levels of complex sphingolipids, specifically glucosylceramide, consistent with a dominant-negative effect of SPTL-1(C121W) that is mediated by loss of this downstream product. Genetic interactions between SPTL-1(C121W) and components of directional trafficking in neurons suggest that the neuronal polarity phenotype could be caused by glycosphingolipid-dependent defects in polarized vesicular trafficking.SIGNIFICANCE STATEMENT The symptoms of inherited metabolic diseases are often attributed to the accumulation of toxic intermediates or byproducts, no matter whether the disease-causing enzyme participates in a biosynthetic or a degradation pathway. By showing that the phenotypes observed in a C. elegans model of HSAN1 disease could be caused by loss of a downstream product (glucosylceramide) rather than the accumulation of a toxic byproduct, our work provides new insights into the origins of the symptoms of inherited metabolic diseases while expanding the repertoire of sphingolipid functions, specifically, of glucosylceramides. These findings not only have their most immediate relevance for neuroprotective treatments for HSAN1, they may also have implications for a much broader range of neurologic conditions.
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29
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Cioni JM, Lin JQ, Holtermann AV, Koppers M, Jakobs MAH, Azizi A, Turner-Bridger B, Shigeoka T, Franze K, Harris WA, Holt CE. Late Endosomes Act as mRNA Translation Platforms and Sustain Mitochondria in Axons. Cell 2019; 176:56-72.e15. [PMID: 30612743 PMCID: PMC6333918 DOI: 10.1016/j.cell.2018.11.030] [Citation(s) in RCA: 248] [Impact Index Per Article: 49.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 09/10/2018] [Accepted: 11/18/2018] [Indexed: 12/14/2022]
Abstract
Local translation regulates the axonal proteome, playing an important role in neuronal wiring and axon maintenance. How axonal mRNAs are localized to specific subcellular sites for translation, however, is not understood. Here we report that RNA granules associate with endosomes along the axons of retinal ganglion cells. RNA-bearing Rab7a late endosomes also associate with ribosomes, and real-time translation imaging reveals that they are sites of local protein synthesis. We show that RNA-bearing late endosomes often pause on mitochondria and that mRNAs encoding proteins for mitochondrial function are translated on Rab7a endosomes. Disruption of Rab7a function with Rab7a mutants, including those associated with Charcot-Marie-Tooth type 2B neuropathy, markedly decreases axonal protein synthesis, impairs mitochondrial function, and compromises axonal viability. Our findings thus reveal that late endosomes interact with RNA granules, translation machinery, and mitochondria and suggest that they serve as sites for regulating the supply of nascent pro-survival proteins in axons. Ribonucleoprotein particles are associated with endosomes in axons Rab7a endosomes provide sites for axonal local translation Rab7a endosomes support axonal synthesis of survival factors CMT2B-Rab7a mutations affect axonal translation and mitochondrial integrity
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Affiliation(s)
- Jean-Michel Cioni
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Julie Qiaojin Lin
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Anne V Holtermann
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Max Koppers
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Maximilian A H Jakobs
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Afnan Azizi
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Benita Turner-Bridger
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Toshiaki Shigeoka
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Kristian Franze
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - William A Harris
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK
| | - Christine E Holt
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK.
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30
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Khamo JS, Krishnamurthy VV, Chen Q, Diao J, Zhang K. Optogenetic Delineation of Receptor Tyrosine Kinase Subcircuits in PC12 Cell Differentiation. Cell Chem Biol 2018; 26:400-410.e3. [PMID: 30595532 DOI: 10.1016/j.chembiol.2018.11.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 08/13/2018] [Accepted: 11/02/2018] [Indexed: 01/19/2023]
Abstract
Nerve growth factor elicits signaling outcomes by interacting with both its high-affinity receptor, TrkA, and its low-affinity receptor, p75NTR. Although these two receptors can regulate distinct cellular outcomes, they both activate the extracellular-signal-regulated kinase pathway upon nerve growth factor stimulation. To delineate TrkA subcircuits in PC12 cell differentiation, we developed an optogenetic system whereby light was used to specifically activate TrkA signaling in the absence of nerve growth factor. By using tyrosine mutants of the optogenetic TrkA in combination with pathway-specific pharmacological inhibition, we find that Y490 and Y785 each contributes to PC12 cell differentiation through the extracellular-signal-regulated kinase pathway in an additive manner. Optogenetic activation of TrkA eliminates the confounding effect of p75NTR and other potential off-target effects of the ligand. This approach can be generalized for the mechanistic study of other receptor-mediated signaling pathways.
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Affiliation(s)
- John S Khamo
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Vishnu V Krishnamurthy
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Qixin Chen
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Jiajie Diao
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA.
| | - Kai Zhang
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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31
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Villarroel-Campos D, Schiavo G, Lazo OM. The many disguises of the signalling endosome. FEBS Lett 2018; 592:3615-3632. [PMID: 30176054 PMCID: PMC6282995 DOI: 10.1002/1873-3468.13235] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 08/29/2018] [Indexed: 01/09/2023]
Abstract
Neurons are highly complex and polarised cells that must overcome a series of logistic challenges to maintain homeostasis across their morphological domains. A very clear example is the propagation of neurotrophic signalling from distal axons, where target-released neurotrophins bind to their receptors and initiate signalling, towards the cell body, where nuclear and cytosolic responses are integrated. The mechanisms of propagation of neurotrophic signalling have been extensively studied and, eventually, the model of a 'signalling endosome', transporting activated receptors and associated complexes, has emerged. Nevertheless, the exact nature of this organelle remains elusive. In this Review, we examine the evidence for the retrograde transport of neurotrophins and their receptors in endosomes, outline some of their diverse physiological and pathological roles, and discuss the main interactors, morphological features and trafficking destinations of a highly flexible endosomal signalling organelle with multiple molecular signatures.
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Affiliation(s)
- David Villarroel-Campos
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, UK
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, UK.,UK Dementia Research Institute at UCL, London, UK.,Discoveries Centre for Regenerative and Precision Medicine, University College London Campus, UK
| | - Oscar Marcelo Lazo
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, UK
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32
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Scott-Solomon E, Kuruvilla R. Mechanisms of neurotrophin trafficking via Trk receptors. Mol Cell Neurosci 2018; 91:25-33. [PMID: 29596897 DOI: 10.1016/j.mcn.2018.03.013] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/19/2018] [Accepted: 03/26/2018] [Indexed: 12/31/2022] Open
Abstract
In neurons, long-distance communication between axon terminals and cell bodies is a critical determinant in establishing and maintaining neural circuits. Neurotrophins are soluble factors secreted by post-synaptic target tissues that retrogradely control axon and dendrite growth, survival, and synaptogenesis of innervating neurons. Neurotrophins bind Trk receptor tyrosine kinases in axon terminals to promote endocytosis of ligand-bound phosphorylated receptors into signaling endosomes. Trk-harboring endosomes function locally in axons to acutely promote growth events, and can also be retrogradely transported long-distances to remote cell bodies and dendrites to stimulate cytoplasmic and transcriptional signaling necessary for neuron survival, morphogenesis, and maturation. Neuronal responsiveness to target-derived neurotrophins also requires the precise axonal targeting of newly synthesized Trk receptors. Recent studies suggest that anterograde delivery of Trk receptors is regulated by retrograde neurotrophin signaling. In this review, we summarize current knowledge on the functions and mechanisms of retrograde trafficking of Trk signaling endosomes, and highlight recent discoveries on the forward trafficking of nascent receptors.
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Affiliation(s)
- Emily Scott-Solomon
- Department of Biology, Johns Hopkins University, 3400 N. Charles St, 227 Mudd Hall, Baltimore, MD 21218, USA
| | - Rejji Kuruvilla
- Department of Biology, Johns Hopkins University, 3400 N. Charles St, 227 Mudd Hall, Baltimore, MD 21218, USA.
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33
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Barford K, Keeler A, McMahon L, McDaniel K, Yap CC, Deppmann CD, Winckler B. Transcytosis of TrkA leads to diversification of dendritic signaling endosomes. Sci Rep 2018; 8:4715. [PMID: 29549340 PMCID: PMC5856830 DOI: 10.1038/s41598-018-23036-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/05/2018] [Indexed: 01/16/2023] Open
Abstract
The development of the peripheral nervous system relies on long-distance signaling from target organs back to the soma. In sympathetic neurons, this long-distance signaling is mediated by target derived Nerve Growth Factor (NGF) interacting with its axonal receptor, TrkA. This ligand receptor complex internalizes into what is commonly referred to as the signaling endosome which is transported retrogradely to the soma and dendrites to mediate survival signaling and synapse formation, respectively. The molecular identity of signaling endosomes in dendrites has not yet been determined. Here, we perform a detailed analysis of TrkA endosomal compartments and trafficking patterns. We find that signaling endosomes are not uniform but molecularly diversified into Rab7 (late endosome) and Rab11 (recycling endosome) populations in axons and dendrites in vitro and in the soma in vivo. Surprisingly, TrkA-NGF signaling endosomes in dendrites undergo dynamic trafficking events, including putative fusion and fission. Overall, we find that signaling endosomes do not remain as a singular endosomal subtype but instead exist in multiple populations that undergo dynamic endosomal trafficking events. These dynamic events might drive functional diversification of the signaling endosome.
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Affiliation(s)
- Kelly Barford
- Department of Cell Biology, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia, 22908, USA
| | - Austin Keeler
- Department of Biology, University of Virginia, Physical Life Sciences Building (PLSB), 90 Geldard Drive, Charlottesville, Virginia, 22903, USA
| | - Lloyd McMahon
- Department of Cell Biology, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia, 22908, USA
| | - Kathryn McDaniel
- Department of Cell Biology, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia, 22908, USA
| | - Chan Choo Yap
- Department of Cell Biology, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia, 22908, USA
| | - Christopher D Deppmann
- Department of Biology, University of Virginia, Physical Life Sciences Building (PLSB), 90 Geldard Drive, Charlottesville, Virginia, 22903, USA. .,Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, 22903, USA.
| | - Bettina Winckler
- Department of Cell Biology, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia, 22908, USA.
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Genetic aberrations in macroautophagy genes leading to diseases. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018. [PMID: 29524522 DOI: 10.1016/j.bbamcr.2018.03.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The catabolic process of macroautophagy, through the rapid degradation of unwanted cellular components, is involved in a multitude of cellular and organismal functions that are essential to maintain homeostasis. Those functions include adaptation to starvation, cell development and differentiation, innate and adaptive immunity, tumor suppression, autophagic cell death, and maintenance of stem cell stemness. Not surprisingly, an impairment or block of macroautophagy can lead to severe pathologies. A still increasing number of reports, in particular, have revealed that mutations in the autophagy-related (ATG) genes, encoding the key players of macroautophagy, are either the cause or represent a risk factor for the development of several illnesses. The aim of this review is to provide a comprehensive overview of the diseases and disorders currently known that are or could be caused by mutations in core ATG proteins but also in the so-called autophagy receptors, which provide specificity to the process of macroautophagy. Our compendium underlines the medical relevance of this pathway and underscores the importance of the eventual development of therapeutic approaches aimed at modulating macroautophagy.
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35
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Banworth MJ, Li G. Consequences of Rab GTPase dysfunction in genetic or acquired human diseases. Small GTPases 2018. [PMID: 29239692 DOI: 10.1080/215412481397833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023] Open
Abstract
Rab GTPases are important regulators of intracellular membrane trafficking in eukaryotes. Both activating and inactivating mutations in Rab genes have been identified and implicated in human diseases ranging from neurological disorders to cancer. In addition, altered Rab expression is often associated with disease prognosis. As such, the study of diseases associated with Rabs or Rab-interacting proteins has shed light on the important role of intracellular membrane trafficking in disease etiology. In this review, we cover recent advances in the field with an emphasis on cellular mechanisms.
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Affiliation(s)
- Marcellus J Banworth
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
| | - Guangpu Li
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
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36
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Kaplan L, Ierokomos A, Chowdary P, Bryant Z, Cui B. Rotation of endosomes demonstrates coordination of molecular motors during axonal transport. SCIENCE ADVANCES 2018; 4:e1602170. [PMID: 29536037 PMCID: PMC5846296 DOI: 10.1126/sciadv.1602170] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 01/30/2018] [Indexed: 05/29/2023]
Abstract
Long-distance axonal transport is critical to the maintenance and function of neurons. Robust transport is ensured by the coordinated activities of multiple molecular motors acting in a team. Conventional live-cell imaging techniques used in axonal transport studies detect this activity by visualizing the translational dynamics of a cargo. However, translational measurements are insensitive to torques induced by motor activities. By using gold nanorods and multichannel polarization microscopy, we simultaneously measure the rotational and translational dynamics for thousands of axonally transported endosomes. We find that the rotational dynamics of an endosome provide complementary information regarding molecular motor activities to the conventionally tracked translational dynamics. Rotational dynamics correlate with translational dynamics, particularly in cases of increased rotation after switches between kinesin- and dynein-mediated transport. Furthermore, unambiguous measurement of nanorod angle shows that endosome-contained nanorods align with the orientation of microtubules, suggesting a direct mechanical linkage between the ligand-receptor complex and the microtubule motors.
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Affiliation(s)
- Luke Kaplan
- Biophysics Program, Stanford University, Stanford, CA 94305, USA
| | - Athena Ierokomos
- Biophysics Program, Stanford University, Stanford, CA 94305, USA
| | - Praveen Chowdary
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
| | - Zev Bryant
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
| | - Bianxiao Cui
- Department of Chemistry, Stanford University, Stanford, CA 94305, USA
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37
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Jin EJ, Kiral FR, Hiesinger PR. The where, what, and when of membrane protein degradation in neurons. Dev Neurobiol 2018; 78:283-297. [PMID: 28884504 PMCID: PMC5816708 DOI: 10.1002/dneu.22534] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 09/01/2017] [Accepted: 09/04/2017] [Indexed: 12/20/2022]
Abstract
Membrane protein turnover and degradation are required for the function and health of all cells. Neurons may live for the entire lifetime of an organism and are highly polarized cells with spatially segregated axonal and dendritic compartments. Both longevity and morphological complexity represent challenges for regulated membrane protein degradation. To investigate how neurons cope with these challenges, an increasing number of recent studies investigated local, cargo-specific protein sorting, and degradation at axon terminals and in dendritic processes. In this review, we explore the current answers to the ensuing questions of where, what, and when membrane proteins are degraded in neurons. © 2017 The Authors Developmental Neurobiology Published by Wiley Periodicals, Inc. Develop Neurobiol 78: 283-297, 2018.
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Affiliation(s)
- Eugene Jennifer Jin
- Division of NeurobiologyInstitute for Biology, Freie Universität Berlin14195 BerlinGermany
- Graduate School of Biomedical SciencesUniversity of Texas Southwestern Medical CenterDallasTX75390USA
| | - Ferdi Ridvan Kiral
- Division of NeurobiologyInstitute for Biology, Freie Universität Berlin14195 BerlinGermany
| | - Peter Robin Hiesinger
- Division of NeurobiologyInstitute for Biology, Freie Universität Berlin14195 BerlinGermany
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38
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Phosphorylation of the Unique C-Terminal Tail of the Alpha Isoform of the Scaffold Protein SH2B1 Controls the Ability of SH2B1α To Enhance Nerve Growth Factor Function. Mol Cell Biol 2018; 38:MCB.00277-17. [PMID: 29229648 DOI: 10.1128/mcb.00277-17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 12/06/2017] [Indexed: 11/20/2022] Open
Abstract
The scaffold protein SH2B1, a major regulator of body weight, is recruited to the receptors of multiple cytokines and growth factors, including nerve growth factor (NGF). The β isoform but not the α isoform of SH2B1 greatly enhances NGF-dependent neurite outgrowth of PC12 cells. Here, we asked how the unique C-terminal tails of the α and β isoforms modulate SH2B1 function. We compared the actions of SH2B1α and SH2B1β to those of the N-terminal 631 amino acids shared by both isoforms. In contrast to the β tail, the α tail inhibited the ability of SH2B1 to both cycle through the nucleus and enhance NGF-mediated neurite outgrowth, gene expression, phosphorylation of Akt and phospholipase C-gamma (PLC-γ), and autophosphorylation of the NGF receptor TrkA. These functions were restored when Tyr753 in the α tail was mutated to phenylalanine. We provide evidence that TrkA phosphorylates Tyr753 in SH2B1α, as well as tyrosines 439 and 55 in both SH2B1α and SH2B1β. Finally, coexpression of SH2B1α but not SH2B1α with a mutation of Y to F at position 753 (Y753F) inhibited the ability of SH2B1β to enhance neurite outgrowth. These results suggest that the C-terminal tails of SH2B1 isoforms are key determinants of the cellular role of SH2B1. Furthermore, the function of SH2B1α is regulated by phosphorylation of the α tail.
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39
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Banworth MJ, Li G. Consequences of Rab GTPase dysfunction in genetic or acquired human diseases. Small GTPases 2017; 9:158-181. [PMID: 29239692 DOI: 10.1080/21541248.2017.1397833] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Rab GTPases are important regulators of intracellular membrane trafficking in eukaryotes. Both activating and inactivating mutations in Rab genes have been identified and implicated in human diseases ranging from neurological disorders to cancer. In addition, altered Rab expression is often associated with disease prognosis. As such, the study of diseases associated with Rabs or Rab-interacting proteins has shed light on the important role of intracellular membrane trafficking in disease etiology. In this review, we cover recent advances in the field with an emphasis on cellular mechanisms.
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Affiliation(s)
- Marcellus J Banworth
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
| | - Guangpu Li
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
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40
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Common and Divergent Mechanisms in Developmental Neuronal Remodeling and Dying Back Neurodegeneration. Curr Biol 2017; 26:R628-R639. [PMID: 27404258 DOI: 10.1016/j.cub.2016.05.025] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cell death is an inherent process that is required for the proper wiring of the nervous system. Studies over the last four decades have shown that, in a parallel developmental pathway, axons and dendrites are eliminated without the death of the neuron. This developmentally regulated 'axonal death' results in neuronal remodeling, which is an essential mechanism to sculpt neuronal networks in both vertebrates and invertebrates. Studies across various organisms have demonstrated that a conserved strategy in the formation of adult neuronal circuitry often involves generating too many connections, most of which are later eliminated with high temporal and spatial resolution. Can neuronal remodeling be regarded as developmentally and spatially regulated neurodegeneration? It has been previously speculated that injury-induced degeneration (Wallerian degeneration) shares some molecular features with 'dying back' neurodegenerative diseases. In this opinion piece, we examine the similarities and differences between the mechanisms regulating neuronal remodeling and those being perturbed in dying back neurodegenerative diseases. We focus primarily on amyotrophic lateral sclerosis and peripheral neuropathies and highlight possible shared pathways and mechanisms. While mechanistic data are only just beginning to emerge, and despite the inherent differences between disease-oriented and developmental processes, we believe that some of the similarities between these developmental and disease-initiated degeneration processes warrant closer collaborations and crosstalk between these different fields.
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41
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Terenzio M, Schiavo G, Fainzilber M. Compartmentalized Signaling in Neurons: From Cell Biology to Neuroscience. Neuron 2017; 96:667-679. [PMID: 29096079 DOI: 10.1016/j.neuron.2017.10.015] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 09/27/2017] [Accepted: 10/09/2017] [Indexed: 12/18/2022]
Abstract
Neurons are the largest known cells, with complex and highly polarized morphologies. As such, neuronal signaling is highly compartmentalized, requiring sophisticated transfer mechanisms to convey and integrate information within and between sub-neuronal compartments. Here, we survey different modes of compartmentalized signaling in neurons, highlighting examples wherein the fundamental cell biological processes of protein synthesis and degradation, membrane trafficking, and organelle transport are employed to enable the encoding and integration of information, locally and globally within a neuron. Comparisons to other cell types indicate that neurons accentuate widely shared mechanisms, providing invaluable models for the compartmentalization and transfer mechanisms required and used by most eukaryotic cells.
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Affiliation(s)
- Marco Terenzio
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Giampietro Schiavo
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London WC1N 3BG, UK; Discoveries Centre for Regenerative and Precision Medicine at UCL, London WC1N 3BG, UK; UK Dementia Research Institute at UCL, London WC1E 6BT, UK
| | - Mike Fainzilber
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 76100, Israel.
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42
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Prior R, Van Helleputte L, Benoy V, Van Den Bosch L. Defective axonal transport: A common pathological mechanism in inherited and acquired peripheral neuropathies. Neurobiol Dis 2017; 105:300-320. [DOI: 10.1016/j.nbd.2017.02.009] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 01/29/2017] [Accepted: 02/20/2017] [Indexed: 12/29/2022] Open
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43
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Laviolette LA, Mermoud J, Calvo IA, Olson N, Boukhali M, Steinlein OK, Roider E, Sattler EC, Huang D, Teh BT, Motamedi M, Haas W, Iliopoulos O. Negative regulation of EGFR signalling by the human folliculin tumour suppressor protein. Nat Commun 2017; 8:15866. [PMID: 28656962 PMCID: PMC5493755 DOI: 10.1038/ncomms15866] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 05/09/2017] [Indexed: 02/01/2023] Open
Abstract
Germline mutations in the Folliculin (FLCN) tumour suppressor gene result in fibrofolliculomas, lung cysts and renal cancers, but the precise mechanisms of tumour suppression by FLCN remain elusive. Here we identify Rab7A, a small GTPase important for endocytic trafficking, as a novel FLCN interacting protein and demonstrate that FLCN acts as a Rab7A GTPase-activating protein. FLCN−/− cells display slower trafficking of epidermal growth factor receptors (EGFR) from early to late endosomes and enhanced activation of EGFR signalling upon ligand stimulation. Reintroduction of wild-type FLCN, but not tumour-associated FLCN mutants, suppresses EGFR signalling in a Rab7A-dependent manner. EGFR signalling is elevated in FLCN−/− tumours and the EGFR inhibitor afatinib suppresses the growth of human FLCN−/− cells as tumour xenografts. The functional interaction between FLCN and Rab7A appears conserved across species. Our work highlights a mechanism explaining, at least in part, the tumour suppressor function of FLCN. Folliculin is a known tumour suppressor but the molecular mechanisms behind this function are unclear. Here the authors show that Folliculin regulates EGFR signalling by modulating its Rab7a-dependent trafficking.
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Affiliation(s)
- Laura A Laviolette
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Julien Mermoud
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Isabel A Calvo
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Nicholas Olson
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Myriam Boukhali
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Ortrud K Steinlein
- Institute of Human Genetics, University Hospital Munich, University of Munich, Munich 80336, Germany
| | - Elisabeth Roider
- Department of Dermatology and Allergology, University Hospital, Ludwig Maximilian University Munich, Munich D-80337, Germany
| | - Elke C Sattler
- Department of Dermatology and Allergology, University Hospital, Ludwig Maximilian University Munich, Munich D-80337, Germany
| | - Dachuan Huang
- Laboratory of Cancer Epigenome, Division of Medical Sciences, National Cancer Centre Singapore, Singapore 169610, Singapore.,Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore 169610, Singapore
| | - Bin Tean Teh
- Laboratory of Cancer Epigenome, Division of Medical Sciences, National Cancer Centre Singapore, Singapore 169610, Singapore.,Cancer and Stem Cell Biology Program, Duke-NUS Medical School, Singapore 169610, Singapore
| | - Mo Motamedi
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Wilhelm Haas
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA
| | - Othon Iliopoulos
- Center for Cancer Research, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, Massachusetts 02139, USA.,Division of Hematology-Oncology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
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44
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Abstract
Recent studies have demonstrated that hyperphosphorylation of tau protein plays a role in neuronal toxicities of α-synuclein (ASYN) in neurodegenerative disease such as familial Alzheimer’s disease (AD), dementia with Lewy bodies (DLB) and Parkinson’s disease. Using a transgenic mouse model of Parkinson’s disease (PD) that expresses GFP-ASYN driven by the PDGF-β promoter, we investigated how accumulation of ASYN impacted axonal function. We found that retrograde axonal trafficking of brain-derived neurotrophic factor (BDNF) in DIV7 cultures of E18 cortical neurons was markedly impaired at the embryonic stage, even though hyperphosphorylation of tau was not detectable in these neurons at this stage. Interestingly, we found that overexpressed ASYN interacted with dynein and induced a significant increase in the activated levels of small Rab GTPases such as Rab5 and Rab7, both key regulators of endocytic processes. Furthermore, expression of ASYN resulted in neuronal atrophy in DIV7 cortical cultures of either from E18 transgenic mouse model or from rat E18 embryos that were transiently transfected with ASYN-GFP for 72 hrs. Our studies suggest that excessive ASYN likely alters endocytic pathways leading to axonal dysfunction in embryonic cortical neurons in PD mouse models.
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45
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Abstract
Neurons are highly polarized cells that exhibit one of the more complex morphology and function. Neuronal intracellular trafficking plays a key role in dictating the directionality and specificity of vesicle formation, transport and fusion, allowing the transmission of information in sophisticate cellular network. Thus, the integrity of protein trafficking and spatial organization is especially important in neuronal cells. RAB proteins, small monomeric GTPases belonging to the RAS superfamily, spatially and temporally orchestrate specific vesicular trafficking steps. In this review we summarise the known roles of RAB GTPases involved in the maintenance of neuronal vesicular trafficking in the central nervous system. In particular, we discriminate the axonal pre-synaptic trafficking and dendritic post-synaptic trafficking, to better underlie how a correct orchestration of vesicle movement is necessary to maintain neuronal polarity and then, to permit an accurate architecture and functionality of synaptic activity.
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Affiliation(s)
- Maria Lidia Mignogna
- a Molecular Genetics of Intellectual Disabilities Unit, Division of Neuroscience at IRCCS San Raffaele Scientific Institute , Milan , Italy
| | - Patrizia D'Adamo
- a Molecular Genetics of Intellectual Disabilities Unit, Division of Neuroscience at IRCCS San Raffaele Scientific Institute , Milan , Italy
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46
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47
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Barford K, Deppmann C, Winckler B. The neurotrophin receptor signaling endosome: Where trafficking meets signaling. Dev Neurobiol 2017; 77:405-418. [PMID: 27503831 DOI: 10.1002/dneu.22427] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 07/05/2016] [Accepted: 08/04/2016] [Indexed: 11/08/2022]
Abstract
Neurons are the largest cells in the body and form subcellular compartments such as axons and dendrites. During both development and adulthood building blocks must be continually trafficked long distances to maintain the different regions of the neuron. Beyond building blocks, signaling complexes are also transported, allowing for example, axons to communicate with the soma. The critical roles of signaling via ligand-receptor complexes is perhaps best illustrated in the context of development, where they are known to regulate polarization, survival, axon outgrowth, dendrite development, and synapse formation. However, knowing 'when' and 'how much' signaling is occurring does not provide the complete story. The location of signaling has a significant impact on the functional outcomes. There are therefore complex and functionally important trafficking mechanisms in place to control the precise spatial and temporal aspects of many signal transduction events. In turn, many of these signaling events affect trafficking mechanisms, setting up an intricate connection between trafficking and signaling. In this review we will use neurotrophin receptors, specifically TrkA and TrkB, to illustrate the cell biology underlying the links between trafficking and signaling. Briefly, we will discuss the concepts of how trafficking and signaling are intimately linked for functional and diverse signaling outputs, and how the same protein can play different roles for the same receptor depending on its localization. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 77: 419-437, 2017.
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Affiliation(s)
- Kelly Barford
- Department of Cell Biology, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia, 22908
| | - Christopher Deppmann
- Department of Biology, University of Virginia, Physical Life Sciences Building (PLSB), 90 Geldard Drive, Charlottesville, Virginia, 22903
| | - Bettina Winckler
- Department of Cell Biology, University of Virginia, 1340 Jefferson Park Avenue, Charlottesville, Virginia, 22908
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48
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Wen H, Zhan L, Chen S, Long L, Xu E. Rab7 may be a novel therapeutic target for neurologic diseases as a key regulator in autophagy. J Neurosci Res 2017; 95:1993-2004. [PMID: 28186670 DOI: 10.1002/jnr.24034] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 01/17/2017] [Accepted: 01/17/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Haixia Wen
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Lixuan Zhan
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Siyuan Chen
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - Long Long
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
| | - En Xu
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University and Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China; Guangzhou China
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49
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Charcot Marie Tooth 2B Peripheral Sensory Neuropathy: How Rab7 Mutations Impact NGF Signaling? Int J Mol Sci 2017; 18:ijms18020324. [PMID: 28165391 PMCID: PMC5343860 DOI: 10.3390/ijms18020324] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/10/2017] [Accepted: 01/15/2017] [Indexed: 12/12/2022] Open
Abstract
Charcot-Marie-Tooth 2B peripheral sensory neuropathy (CMT2B) is a debilitating autosomal dominant hereditary sensory neuropathy. Patients with this disease lose pain sensation and frequently need amputation. Axonal dysfunction and degeneration of peripheral sensory neurons is a major clinical manifestation of CMT2B. However, the cellular and molecular pathogenic mechanisms remain undefined. CMT2B is caused by missense point mutations (L129F, K157N, N161T/I, V162M) in Rab7 GTPase. Strong evidence suggests that the Rab7 mutation(s) enhances the cellular levels of activated Rab7 proteins, thus resulting in increased lysosomal activity and autophagy. As a consequence, trafficking and signaling of neurotrophic factors such as nerve growth factor (NGF) in the long axons of peripheral sensory neurons are particularly vulnerable to premature degradation. A “gain of toxicity” model has, thus, been proposed based on these observations. However, studies of fly photo-sensory neurons indicate that the Rab7 mutation(s) causes a “loss of function”, resulting in haploinsufficiency. In the review, we summarize experimental evidence for both hypotheses. We argue that better models (rodent animals and human neurons) of CMT2B are needed to precisely define the disease mechanisms.
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Oscillating Magnet Array-Based Nanomagnetic Gene Transfection: A Valuable Tool for Molecular Neurobiology Studies. NANOMATERIALS 2017; 7:nano7020028. [PMID: 28336862 PMCID: PMC5333013 DOI: 10.3390/nano7020028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/20/2017] [Accepted: 01/23/2017] [Indexed: 12/12/2022]
Abstract
To develop treatments for neurodegenerative disorders, it is critical to understand the biology and function of neurons in both normal and diseased states. Molecular studies of neurons involve the delivery of small biomolecules into cultured neurons via transfection to study genetic variants. However, as cultured primary neurons are sensitive to temperature change, stress, and shifts in pH, these factors make biomolecule delivery difficult, particularly non-viral delivery. Herein we used oscillating nanomagnetic gene transfection to successfully transfect SH-SY5Y cells as well as primary hippocampal and cortical neurons on different days in vitro. This novel technique has been used to effectively deliver genetic material into various cell types, resulting in high transfection efficiency and viability. From these observations and other related studies, we suggest that oscillating nanomagnetic gene transfection is an effective method for gene delivery into hard-to-transfect neuronal cell types.
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