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Alsaadi H, Peller J, Ghasemlou N, Kawaja MD. Immunohistochemical phenotype of sensory neurons associated with sympathetic plexuses in the trigeminal ganglia of adult nerve growth factor transgenic mice. J Comp Neurol 2024; 532:e25563. [PMID: 37986234 DOI: 10.1002/cne.25563] [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] [Indexed: 11/22/2023]
Abstract
Following peripheral nerve injury, postganglionic sympathetic axons sprout into the affected sensory ganglia and form perineuronal sympathetic plexuses with somata of sensory neurons. This sympathosensory coupling contributes to the onset and persistence of injury-induced chronic pain. We have documented the presence of similar sympathetic plexuses in the trigeminal ganglia of adult mice that ectopically overexpress nerve growth factor (NGF), in the absence of nerve injury. In this study, we sought to further define the phenotype(s) of these trigeminal sensory neurons having sympathetic plexuses in our transgenic mice. Using quantitative immunofluorescence staining analyses, we show that the invading sympathetic axons specifically target sensory somata immunopositive for several biomarkers: NGF high-affinity receptor tyrosine kinase A (trkA), calcitonin gene-related peptide (CGRP), neurofilament heavy chain (NFH), and P2X purinoceptor 3 (P2X3). Based on these phenotypic characteristics, the majority of the sensory somata surrounded by sympathetic plexuses are likely to be NGF-responsive nociceptors (i.e., trkA expressing) that are peptidergic (i.e., CGRP expressing), myelinated (i.e., NFH expressing), and ATP sensitive (i.e., P2X3 expressing). Our data also show that very few sympathetic plexuses surround sensory somata expressing other nociceptive (pain) biomarkers, including substance P and acid-sensing ion channel 3. No sympathetic plexuses are associated with sensory somata that display isolectin B4 binding. Though the cellular mechanisms that trigger the formation of sympathetic plexus (with and without nerve injury) remain unknown, our new observations yield an unexpected specificity with which invading sympathetic axons appear to target a precise subtype of nociceptors. This selectivity likely contributes to pain development and maintenance associated with sympathosensory coupling.
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Affiliation(s)
- Hanin Alsaadi
- Center for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - Jacob Peller
- Center for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - Nader Ghasemlou
- Center for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
- Department of Anesthesiology and Perioperative Medicine, School of Medicine, Queen's University, Kingston, Ontario, Canada
- Department of Biomedical and Molecular Sciences, School of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Michael D Kawaja
- Center for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
- Department of Biomedical and Molecular Sciences, School of Medicine, Queen's University, Kingston, Ontario, Canada
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2
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Conroy JN, Coulson EJ. High-affinity TrkA and p75 neurotrophin receptor complexes: a twisted affair. J Biol Chem 2022; 298:101568. [PMID: 35051416 PMCID: PMC8889134 DOI: 10.1016/j.jbc.2022.101568] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 12/10/2021] [Accepted: 12/13/2021] [Indexed: 10/27/2022] Open
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3
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Franco ML, Nadezhdin KD, Light TP, Goncharuk SA, Soler-Lopez A, Ahmed F, Mineev KS, Hristova K, Arseniev AS, Vilar M. Interaction between the transmembrane domains of neurotrophin receptors p75 and TrkA mediates their reciprocal activation. J Biol Chem 2021; 297:100926. [PMID: 34216618 PMCID: PMC8327350 DOI: 10.1016/j.jbc.2021.100926] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/25/2021] [Accepted: 06/28/2021] [Indexed: 11/23/2022] Open
Abstract
The neurotrophin receptors p75 and tyrosine protein kinase receptor A (TrkA) play important roles in the development and survival of the nervous system. Biochemical data suggest that p75 and TrkA reciprocally regulate the activities of each other. For instance, p75 is able to regulate the response of TrkA to lower concentrations of nerve growth factor (NGF), and TrkA promotes shedding of the extracellular domain of p75 by α-secretases in a ligand-dependent manner. The current model suggests that p75 and TrkA are regulated by means of a direct physical interaction; however, the nature of such interaction has been elusive thus far. Here, using NMR in micelles, multiscale molecular dynamics, FRET, and functional studies, we identified and characterized the direct interaction between TrkA and p75 through their respective transmembrane domains (TMDs). Molecular dynamics of p75-TMD mutants suggests that although the interaction between TrkA and p75 TMDs is maintained upon mutation, a specific protein interface is required to facilitate TrkA active homodimerization in the presence of NGF. The same mutations in the TMD protein interface of p75 reduced the activation of TrkA by NGF as well as reducing cell differentiation. In summary, we provide a structural model of the p75-TrkA receptor complex necessary for neuronal development stabilized by TMD interactions.
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Affiliation(s)
- María L Franco
- Unit of Molecular Basis of Neurodegeneration, Institute of Biomedicine CSIC, València, Spain
| | - Kirill D Nadezhdin
- Department of Structural Biology, Laboratory of NMR-Spectroscopy, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, Russian Federation
| | - Taylor P Light
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Sergey A Goncharuk
- Department of Structural Biology, Laboratory of NMR-Spectroscopy, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, Russian Federation; Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology, Moscow, Russian Federation
| | - Andrea Soler-Lopez
- Unit of Molecular Basis of Neurodegeneration, Institute of Biomedicine CSIC, València, Spain
| | - Fozia Ahmed
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Konstantin S Mineev
- Department of Structural Biology, Laboratory of NMR-Spectroscopy, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, Russian Federation; Phystech School of Biological and Medical Physics, Moscow Institute of Physics and Technology, Moscow, Russian Federation
| | - Kalina Hristova
- Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Alexander S Arseniev
- Department of Structural Biology, Laboratory of NMR-Spectroscopy, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry of the Russian Academy of Sciences, Moscow, Russian Federation.
| | - Marçal Vilar
- Unit of Molecular Basis of Neurodegeneration, Institute of Biomedicine CSIC, València, Spain.
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4
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Liu Z, Wu H, Huang S. Role of NGF and its receptors in wound healing (Review). Exp Ther Med 2021; 21:599. [PMID: 33884037 PMCID: PMC8056114 DOI: 10.3892/etm.2021.10031] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 03/08/2021] [Indexed: 12/17/2022] Open
Abstract
Wound healing is an important and complicated process that includes four highly integrated and overlapping phases, haemostasis, inflammation, proliferation and tissue remodelling. Nerve growth factor (NGF) was the first member of a family of neurotrophic factors to be discovered, and is an essential neurotrophic factor for the development and maintenance of the central and peripheral nervous systems. Several studies have proposed that NGF and its receptors, tropomyosin-related kinase receptor 1 and NGF receptor, are involved in the wound healing process, and are important components of the healing of several wounds both in vivo and in vitro. Topical application of NGF significantly promotes the healing of different types of wounds, including diabetic foot ulcers, pressure ulcers and corneal wounds. The present review summarizes the status of NGF and its receptors in current literature, and discusses data obtained in the last few years on the healing action of NGF in cutaneous, corneal and oral wounds.
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Affiliation(s)
- Zhenxing Liu
- Department of Oral and Maxillofacial Surgery, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, P.R. China
| | - Haiwei Wu
- Department of Oral and Maxillofacial Surgery, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, P.R. China
| | - Shengyun Huang
- Department of Oral and Maxillofacial Surgery, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, P.R. China
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Colardo M, Martella N, Pensabene D, Siteni S, Di Bartolomeo S, Pallottini V, Segatto M. Neurotrophins as Key Regulators of Cell Metabolism: Implications for Cholesterol Homeostasis. Int J Mol Sci 2021; 22:5692. [PMID: 34073639 PMCID: PMC8198482 DOI: 10.3390/ijms22115692] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 12/14/2022] Open
Abstract
Neurotrophins constitute a family of growth factors initially characterized as predominant mediators of nervous system development, neuronal survival, regeneration and plasticity. Their biological activity is promoted by the binding of two different types of receptors, leading to the generation of multiple and variegated signaling cascades in the target cells. Increasing evidence indicates that neurotrophins are also emerging as crucial regulators of metabolic processes in both neuronal and non-neuronal cells. In this context, it has been reported that neurotrophins affect redox balance, autophagy, glucose homeostasis and energy expenditure. Additionally, the trophic support provided by these secreted factors may involve the regulation of cholesterol metabolism. In this review, we examine the neurotrophins' signaling pathways and their effects on metabolism by critically discussing the most up-to-date information. In particular, we gather experimental evidence demonstrating the impact of these growth factors on cholesterol metabolism.
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Affiliation(s)
- Mayra Colardo
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Italy; (M.C.); (N.M.); (D.P.); (S.D.B.)
| | - Noemi Martella
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Italy; (M.C.); (N.M.); (D.P.); (S.D.B.)
| | - Daniele Pensabene
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Italy; (M.C.); (N.M.); (D.P.); (S.D.B.)
| | - Silvia Siteni
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA;
| | - Sabrina Di Bartolomeo
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Italy; (M.C.); (N.M.); (D.P.); (S.D.B.)
| | - Valentina Pallottini
- Department of Science, University Roma Tre, Viale Marconi 446, 00146 Rome, Italy;
- Neuroendocrinology Metabolism and Neuropharmacology Unit, IRCSS Fondazione Santa Lucia, Via del Fosso Fiorano 64, 00143 Rome, Italy
| | - Marco Segatto
- Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche, Italy; (M.C.); (N.M.); (D.P.); (S.D.B.)
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6
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Esmaeili A, Dini S, Pourveiseh A, Esmaeili A. Gene expression patterns of neurotrophin receptors during neuronal differentiation of human exfoliated deciduous teeth. Arch Oral Biol 2021; 127:105138. [PMID: 33940515 DOI: 10.1016/j.archoralbio.2021.105138] [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: 02/17/2021] [Revised: 03/29/2021] [Accepted: 04/24/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVE In the current study, we aimed to investigate the expression profile of TrkA, TrkB, TrkC, and p75NTR neurotrophin receptors because of their roles in the functional differentiation of human exfoliated deciduous teeth (SHED) cells into neural-like cells before and after differentiation of SHED cells into neural-like cells. DESIGN Total RNAs isolated from dental pulp tissue, SHED cells, and neural-like cells were reverse transcribed into complementary DNA. Neurotrophin receptor expression at mRNA and protein levels were compared in these three cell types by means of real-time PCR and western blot methods. RESULTS TrkA mRNA increased (713.6 ± 251.5) significantly (p < 0.01) in neural-like cells difference from SHED and TrkB mRNA enhanced to 3618 times in these cells. The expression pattern of TrkC was very similar to the pattern of TrkA, and B. p75NTR mRNA increased 41.99 ± 21.61 fold in neural-like cells and 9.805 ± 4.06 fold in SHED cells. Almost the same pattern was observed for the expression of these receptors at the protein levels. Alterations with different grades and trends in neurotrophin receptors mRNA and protein expression levels were observed in these cells. CONCLUSION Neurotrophin receptors are important in the existence and differentiation of SHED cells into neuron cells. Therefore, because of the neurogenic potential and accessibility of SHED cells, derived cells from SHED cells can be distinguished as an ideal source for tissue engineering.
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Affiliation(s)
- Ali Esmaeili
- Dental School, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Solmaz Dini
- Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, P.O. Box: 8174673441, Iran
| | - Azadeh Pourveiseh
- Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, P.O. Box: 8174673441, Iran
| | - Abolghasem Esmaeili
- Department of Cell and Molecular Biology & Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, P.O. Box: 8174673441, Iran.
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7
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Dorschner BW, Wiedemuth R, Funke AC, Gentzel M, Rogers ML, Brenner S, Thieme S. Listening to the Whispers in Neuroimmune Crosstalk: A Comprehensive Workflow to Investigate Neurotrophin Receptor p75NTR Under Endogenous, Low Abundance Conditions. Front Immunol 2021; 12:648283. [PMID: 33936068 PMCID: PMC8085361 DOI: 10.3389/fimmu.2021.648283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 03/22/2021] [Indexed: 11/24/2022] Open
Abstract
Inflammatory conditions are critically influenced by neuroimmune crosstalk. Cytokines and neurotrophic factors shape the responses of both nervous and immune systems. Although much progress has been made, most findings to date are based on expression of recombinant (tagged) proteins. The examination of receptor interactions by immunoprecipitation (IP) at endogenous levels provides further insight into the more subtle regulations of immune responses. Here, we present a comprehensive workflow and an optimized IP protocol that provide step-by-step instructions to investigate neurotrophin receptor p75NTR at endogenous, low abundance levels: from lysate preparation and confirmation of receptor expression to antibody validation and successful detection of protein-protein interactions. We employ human melanoma cell line A375 to validate specific antibodies and IP conditions, and apply these methods to explore p75NTR interactions in human leukemic plasmacytoid dendritic cell line PMDC05 detecting 14-3-3ϵ:p75NTR interaction in this cell type. With p75NTR as an exemplary protein, our approach provides a strategy to detect specific interaction partners even under endogenous, low abundance expression conditions.
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Affiliation(s)
- Benjamin W Dorschner
- Experimental Hematology, Department of Pediatrics, University Clinic Carl Gustav Carus, Dresden, Germany
| | - Ralf Wiedemuth
- Experimental Hematology, Department of Pediatrics, University Clinic Carl Gustav Carus, Dresden, Germany
| | - Ann-Christin Funke
- Experimental Hematology, Department of Pediatrics, University Clinic Carl Gustav Carus, Dresden, Germany
| | - Marc Gentzel
- Molecular Analysis - Mass Spectrometry, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universitaet Dresden, Dresden, Germany
| | - Mary-Louise Rogers
- Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Sebastian Brenner
- Experimental Hematology, Department of Pediatrics, University Clinic Carl Gustav Carus, Dresden, Germany
| | - Sebastian Thieme
- Experimental Hematology, Department of Pediatrics, University Clinic Carl Gustav Carus, Dresden, Germany
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8
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Vilar M. Structural Characterization of the p75 Neurotrophin Receptor: A Stranger in the TNFR Superfamily. VITAMINS AND HORMONES 2016; 104:57-87. [PMID: 28215307 DOI: 10.1016/bs.vh.2016.10.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Although p75 neurotrophin receptor (p75NTR) was the founding member of the tumor necrosis factor (TNF) receptor superfamily (TNFRSF), it is an atypical TNFRSF protein. p75NTR like TNF-R1 and Fas-R contain an extracellular domain with four cysteine-rich domains (CRD) and a death domain (DD) in the intracellular region. While TNFRSF proteins are activated by trimeric TNFSF ligands, p75NTR forms dimers activated by dimeric neurotrophins that are structurally unrelated to TNFSF proteins. In addition, although p75NTR shares with other members the interaction with the TNF receptor-associated factors to activate the NF-κB and cell death pathways, p75NTR does not interact with the DD-containing proteins FADD, TRADD, or MyD88. By contrast, the DD of p75NTR is able to recruit several protein interactors via a full catalog of DD interactions not described before in the TNFRSF. p75-DD forms homotypic symmetrical DD-DD complexes with itself and with the related p45-DD; forms heterotypic DD-CARD interactions with the RIP2-CARD domain, and forms a new interaction between a DD and RhoGDI. All these features, in addition to its promiscuous interactions with several ligands and coreceptors, its processing by α- and γ-secretases, the dimeric nature of its transmembrane domain and its "special" juxtamembrane region, make p75NTR a truly stranger in the TNFR superfamily. In this chapter, I will summarize the known structural aspects of p75NTR and I will analyze from a structural point of view, the similitudes and differences between p75NTR and the other members of the TNFRSF.
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Affiliation(s)
- M Vilar
- Molecular Basis of Neurodegeneration Unit, Institute of Biomedicine of Valencia (IBV-CSIC), València, Spain.
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9
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Ultrasound Microbubbles Enhance the Neuroprotective Effect of Mouse Nerve Growth Factor on Intraocular Hypertension-Induced Neuroretina Damage in Rabbits. J Ophthalmol 2016; 2016:4235923. [PMID: 27994883 PMCID: PMC5138486 DOI: 10.1155/2016/4235923] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 09/30/2016] [Accepted: 10/10/2016] [Indexed: 12/29/2022] Open
Abstract
Ultrasound microbubble combined optic protection drugs have obvious protective effect on optic nerve damage. This way of targeting drug delivery is becoming more simple, not through the whole body metabolism, avoiding drug via blood circulation when facing the decomposition and the environment in the interference and destruction process of drugs, to maximize the guarantee to reach target organs of drug concentration and to reache the maximum therapeutic effect. The technique of ultrasound microbubbles is safe, controllable, nonimmunogenic, and repeatable. It provides us with a novel idea in the administration of neuroprotective drugs.
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10
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Pingitore A, Caroleo MC, Cione E, Castañera Gonzalez R, Huang GC, Persaud SJ. Fine tuning of insulin secretion by release of nerve growth factor from mouse and human islet β-cells. Mol Cell Endocrinol 2016; 436:23-32. [PMID: 27424144 DOI: 10.1016/j.mce.2016.07.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 06/13/2016] [Accepted: 07/11/2016] [Indexed: 11/21/2022]
Abstract
Nerve growth factor (NGF) is a protein required for neuronal development that also has regulatory functions in non-neuronal cells. Both NGF and its membrane receptors trkA and p75(NTR) are expressed by islet β-cells. In this study we dynamically profiled NGF secretion from islets and used selective trkA and p75(NTR) inhibitors to identify the role of endogenous NGF in β-cell stimulus-secretion coupling. NGF secretion from mouse islets was transient and did not accompany the sustained second phase of glucose-induced insulin secretion. Despite being present in human islets, NGF was not released at sufficient levels to be quantified. Inhibition of NGF signaling through trkA and p75(NTR) increased basal insulin secretion from both human and mouse islets, but impaired glucose-stimulated insulin secretion. These data support a role for islet NGF in fine-tuning insulin secretion, to both maintain a low basal level of insulin output and contribute to the biphasic secretory response to glucose.
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Affiliation(s)
- Attilio Pingitore
- Diabetes Research Group, Diabetes & Nutritional Sciences Division, King's College London, Guy's Campus, SE1 1UL, London, United Kingdom
| | - Maria Cristina Caroleo
- Department of Pharmacy, Nutritional and Health Sciences, University of Calabria, Via Savinio, 87036, Rende, Italy
| | - Erika Cione
- Department of Pharmacy, Nutritional and Health Sciences, University of Calabria, Via Savinio, 87036, Rende, Italy
| | - Ramon Castañera Gonzalez
- Department of General Surgery, Rio Carrión Hospital, University Hospital Complex of Palencia, 34005, Palencia, Spain
| | - Guo Cai Huang
- Diabetes Research Group, Diabetes & Nutritional Sciences Division, King's College London, Guy's Campus, SE1 1UL, London, United Kingdom
| | - Shanta J Persaud
- Diabetes Research Group, Diabetes & Nutritional Sciences Division, King's College London, Guy's Campus, SE1 1UL, London, United Kingdom.
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11
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Matusica D, Alfonsi F, Turner BJ, Butler TJ, Shepheard SR, Rogers ML, Skeldal S, Underwood CK, Mangelsdorf M, Coulson EJ. Inhibition of motor neuron death in vitro and in vivo by a p75 neurotrophin receptor intracellular domain fragment. J Cell Sci 2015; 129:517-30. [PMID: 26503157 DOI: 10.1242/jcs.173864] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 10/22/2015] [Indexed: 12/14/2022] Open
Abstract
The p75 neurotrophin receptor (p75(NTR); also known as NGFR) can mediate neuronal apoptosis in disease or following trauma, and facilitate survival through interactions with Trk receptors. Here we tested the ability of a p75(NTR)-derived trophic cell-permeable peptide, c29, to inhibit p75(NTR)-mediated motor neuron death. Acute c29 application to axotomized motor neuron axons decreased cell death, and systemic c29 treatment of SOD1(G93A) mice, a common model of amyotrophic lateral sclerosis, resulted in increased spinal motor neuron survival mid-disease as well as delayed disease onset. Coincident with this, c29 treatment of these mice reduced the production of p75(NTR) cleavage products. Although c29 treatment inhibited mature- and pro-nerve-growth-factor-induced death of cultured motor neurons, and these ligands induced the cleavage of p75(NTR) in motor-neuron-like NSC-34 cells, there was no direct effect of c29 on p75(NTR) cleavage. Rather, c29 promoted motor neuron survival in vitro by enhancing the activation of TrkB-dependent signaling pathways, provided that low levels of brain-derived neurotrophic factor (BDNF) were present, an effect that was replicated in vivo in SOD1(G93A) mice. We conclude that the c29 peptide facilitates BDNF-dependent survival of motor neurons in vitro and in vivo.
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Affiliation(s)
- Dusan Matusica
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia Department of Anatomy & Histology, Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| | - Fabienne Alfonsi
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Bradley J Turner
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville 3052, Victoria 3051, Australia
| | - Tim J Butler
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Stephanie R Shepheard
- Department of Human Physiology, Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| | - Mary-Louise Rogers
- Department of Human Physiology, Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide, South Australia 5001, Australia
| | - Sune Skeldal
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Clare K Underwood
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Marie Mangelsdorf
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Elizabeth J Coulson
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
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12
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Covaceuszach S, Konarev PV, Cassetta A, Paoletti F, Svergun DI, Lamba D, Cattaneo A. The conundrum of the high-affinity NGF binding site formation unveiled? Biophys J 2015; 108:687-97. [PMID: 25650935 PMCID: PMC4317559 DOI: 10.1016/j.bpj.2014.11.3485] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 11/05/2014] [Accepted: 11/07/2014] [Indexed: 11/15/2022] Open
Abstract
The homodimer NGF (nerve growth factor) exerts its neuronal activity upon binding to either or both distinct transmembrane receptors TrkA and p75(NTR). Functionally relevant interactions between NGF and these receptors have been proposed, on the basis of binding and signaling experiments. Namely, a ternary TrkA/NGF/p75(NTR) complex is assumed to be crucial for the formation of the so-called high-affinity NGF binding sites. However, the existence, on the cell surface, of direct extracellular interactions is still a matter of controversy. Here, supported by a small-angle x-ray scattering solution study of human NGF, we propose that it is the oligomerization state of the secreted NGF that may drive the formation of the ternary heterocomplex. Our data demonstrate the occurrence in solution of a concentration-dependent distribution of dimers and dimer of dimers. A head-to-head molecular assembly configuration of the NGF dimer of dimers has been validated. Overall, these findings prompted us to suggest a new, to our knowledge, model for the transient ternary heterocomplex, i.e., a TrkA/NGF/p75(NTR) ligand/receptors molecular assembly with a (2:4:2) stoichiometry. This model would neatly solve the problem posed by the unconventional orientation of p75(NTR) with respect to TrkA, as being found in the crystal structures of the TrkA/NGF and p75(NTR)/NGF complexes.
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Affiliation(s)
- Sonia Covaceuszach
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Trieste, Italy
| | - Petr V Konarev
- European Molecular Biology Laboratory, Hamburg Outstation, Hamburg, Germany; Institute of Crystallography, Russian Academy of Sciences, Moscow, Russia
| | - Alberto Cassetta
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Trieste, Italy
| | | | - Dmitri I Svergun
- European Molecular Biology Laboratory, Hamburg Outstation, Hamburg, Germany
| | - Doriano Lamba
- Istituto di Cristallografia, Consiglio Nazionale delle Ricerche, Trieste, Italy.
| | - Antonino Cattaneo
- European Brain Research Institute, Roma, Italy; Scuola Normale Superiore, Pisa, Italy.
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13
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Caroleo MC, Carito V, Pingitore A, Perrotta ID, Perri M, Mancuso D, Russo A, Cione E. Human kidney podocyte cell population as a novel biological target of nerve growth factor. Growth Factors 2015; 33:14-22. [PMID: 25347785 DOI: 10.3109/08977194.2014.975799] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Human podocytes are highly specialized cells with a key role in kidney physiology. Alteration of their structure as a consequence of injury or developmental failure leads to severe renal diseases. Although several studies have tried to elucidate the molecular framework of this cellular system, the functional bases for the maintenance of podocytes in their specialized state to sustain kidney barrier filtration are not completely understood. In this study, the capability of podocytes to produce and secrete the nerve growth factor (NGF) has been demonstrated via a validated in vitro model. During the process of cell differentiation, NGF and its receptors are modulated in human podocytes just as NGF-responsive neurons. Blockade of NGF biological activity results in severe changes of cell morphology. Collectively, our results outline a novel function of the neurotrophin and add a new cellular target in the complex biological framework of NGF.
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Affiliation(s)
- Maria Cristina Caroleo
- Department of Pharmacy, Nutrition and Health Sciences, University of Calabria , Cosenza , Italy
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14
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Toni T, Dua P, van der Graaf PH. Systems Pharmacology of the NGF Signaling Through p75 and TrkA Receptors. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2014; 3:e150. [PMID: 25470184 PMCID: PMC4288001 DOI: 10.1038/psp.2014.48] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 09/12/2014] [Indexed: 02/07/2023]
Abstract
The nerve growth factor (NGF) pathway has been shown to play a key role in pain treatment. Recently, a systems pharmacology model has been proposed that can aid in the identification and validation of drug targets in the NGF pathway. However, this model did not include the role of the p75 receptor, which modulates the signaling of NGF through the tropomyosin receptor kinase A (TrkA). The precise mechanism of the interaction between these two receptors has not been completely elucidated, and we therefore adopted a systems pharmacology modeling approach to gain understanding of the effect of p75 on the dynamics of NGF signal transduction. Specifically, models were developed for the so-called heterodimer and for the ligand-passing hypotheses. We used the model to compare the effect of inhibition of NGF and TrkA and its implication for drug discovery and development for pain treatment.
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Affiliation(s)
- T Toni
- Department of Life Sciences, Imperial College London, London, UK
| | - P Dua
- Pharmatherapeutics Research Clinical Pharmacology, Pfizer Neusentis, Cambridge, UK
| | - P H van der Graaf
- Leiden Academic Centre for Drug Research (LACDR), Systems Pharmacology Cluster, Leiden, The Netherlands
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15
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Novel therapeutic approach for neurogenic erectile dysfunction: effect of neurotrophic tyrosine kinase receptor type 1 monoclonal antibody. Eur Urol 2014; 67:716-26. [PMID: 25847857 DOI: 10.1016/j.eururo.2014.10.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 10/08/2014] [Indexed: 01/19/2023]
Abstract
BACKGROUND Erectile dysfunction (ED) is a major health issue in aged populations, and neurogenic ED is particularly difficult to treat. Novel therapeutic approaches are needed for treatment of neurogenic ED of peripheral origin. OBJECTIVE To investigate the therapeutic effects of a neurotrophic tyrosine kinase receptor type 1 monoclonal antibody (TrkA-mAb) on erectile function and sexual behavior in a rat model of cavernous nerve injury (CNI). DESIGN, SETTING, AND PARTICIPANTS In one experiment, 84 male rats were randomly assigned to seven groups. The groups underwent either CNI or sham surgery, subsequent injection into the major pelvic ganglion (IMPG) of phosphate-buffered saline (PBS), an immunoglobulin G (IgG) control, or TrkA-mAb, and then intracavernosal (IC) injection of either PBS or varying TrkA-mAb concentrations immediately after surgery and then 1 wk later. Erectile function was assessed and histologic/molecular analyses were performed at 6 wk after surgery. In a second experiment, 36 male rats were randomly divided into three groups. The groups underwent CNI or sham surgery and then IC injection of PBS, IgG, or TrkA-mAb immediately after surgery and for 5 wk thereafter. At 6 wk after surgery, the performance of the rats in sexual behavior tests was videotaped. INTERVENTION CNI or sham surgery; IMPG of PBS, IgG, or TrkA-mAb; IC injection of PBS or TrkA-mAb. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS The intracavernous pressure response to cavernous nerve electrostimulation was measured and midpenile cross-sections were histologically examined. Western blotting (WB) of cavernous tissue protein was performed. Rats were assessed for chasing, mounting, intromission, and ejaculation behaviors during sexual behavior tests. The data were analyzed using one-way analysis of variance followed by the Tukey-Kramer t test. RESULTS AND LIMITATIONS Recovery of erectile function of varying degrees was observed in the TrkA-mAb groups. TrkA-mAb treatment significantly suppressed tyrosine hydroxylase-positive nerve fibers in the corpus cavernosum and enhanced neuronal nitric oxide synthase-positive fibers in the dorsal nerve. The ratio of smooth muscle to collagen in the corpus cavernosum was significantly improved in TrkA-mAb treatment groups compared to PBS vehicle and IgG control groups. WB confirmed these biological changes. There was a nonsignificant increase in the average number of intromissions and ejaculations in the TrkA-mAb group. The study limitations include small sample size, variability in sexual behavior, lack of data on the neuromuscular mechanism involved, and lack of information of the role of neurotrophins or cytokines in regeneration. CONCLUSIONS TrkA-mAb successfully inhibits sympathetic nerve regeneration, leads to parasympathetic nerve regeneration, and has therapeutic effects on ED and sexual behavior disorder in a rat model of CNI. PATIENT SUMMARY This report provides strong evidence that a neurotrophic tyrosine kinase receptor type 1 monoclonal antibody (TrkA-mAb) inhibits sympathetic nerve regeneration, leads to parasympathetic nerve regeneration, and has therapeutic effects on erectile dysfunction and sexual behavior disorder in a rat model of cavernous nerve injury. The results raise the possibility that human patients with neurogenic erectile dysfunction may respond to TrkA-mAb in a manner that parallels the response seen in our rodent study.
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16
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Smithson LJ, Krol KM, Kawaja MD. Neuronal degeneration associated with sympathosensory plexuses in the trigeminal ganglia of aged mice that overexpress nerve growth factor. Neurobiol Aging 2014; 35:2812-2821. [PMID: 25037287 DOI: 10.1016/j.neurobiolaging.2014.06.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 05/15/2014] [Accepted: 06/10/2014] [Indexed: 10/25/2022]
Abstract
Aberrant sympathetic sprouting is seen in the uninjured trigeminal ganglia of transgenic mice that ectopically express nerve growth factor under the control of the glial fibrillary acidic protein promoter. These sympathetic axons form perineuronal plexuses around a subset of sensory somata in 2- to 3-month-old transgenic mice. Here, we show that aged transgenic mice (i.e., 11-14 and 16-18 months old) have dystrophic sympathetic plexuses (i.e., increased densities of swollen axons), and that satellite glial cells, specifically those in contact with dystrophic plexuses in the aged mice display strong immunostaining for tumor necrosis factor alpha. The colocalization of dystrophic plexuses and reactive satellite glial cells in the aged mice coincides with degenerative features in the enveloped sensory somata. Collectively, these novel results show that, with advancing age, sympathetic plexuses undergo dystrophic changes that heighten satellite glial cell reactivity and that together these cellular events coincide with neuronal degeneration.
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Affiliation(s)
- Laura J Smithson
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - Karmen M Krol
- Department of Anesthesiology, Queen's University, Kingston, Ontario, Canada
| | - Michael D Kawaja
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada.
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Matusica D, Skeldal S, Sykes AM, Palstra N, Sharma A, Coulson EJ. An intracellular domain fragment of the p75 neurotrophin receptor (p75(NTR)) enhances tropomyosin receptor kinase A (TrkA) receptor function. J Biol Chem 2013; 288:11144-54. [PMID: 23471969 PMCID: PMC3630867 DOI: 10.1074/jbc.m112.436469] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 02/17/2013] [Indexed: 11/06/2022] Open
Abstract
Facilitation of nerve growth factor (NGF) signaling by the p75 neurotrophin receptor (p75(NTR)) is critical for neuronal survival and differentiation. However, the interaction between p75(NTR) and TrkA receptors required for this activity is not understood. Here, we report that a specific 29-amino acid peptide derived from the intracellular domain fragment of p75(NTR) interacts with and potentiates binding of NGF to TrkA-expressing cells, leading to increased neurite outgrowth in sympathetic neurons as a result of enhanced Erk1/2 and Akt signaling. An endogenous intracellular domain fragment of p75(NTR) (p75(ICD)) containing these 29 amino acids is produced by regulated proteolysis of the full-length receptor. We demonstrate that generation of this fragment is a requirement for p75(NTR) to facilitate TrkA signaling in neurons and propose that the juxtamembrane region of p75(ICD) acts to cause a conformational change within the extracellular domain of TrkA. This finding provides new insight into the mechanism by which p75(NTR) and TrkA interact to enhance neurotrophic signaling.
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Affiliation(s)
- Dusan Matusica
- From the Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Sune Skeldal
- From the Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Alex M. Sykes
- From the Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Nickless Palstra
- From the Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Aanchal Sharma
- From the Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Elizabeth J. Coulson
- From the Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
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18
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Papandreou CN, Bogenrieder T, Finstad CL, Freeman RH, Chao MV, Albino AP, Scher HI, Reuter VE, Nanus DM. Reversal of the low-affinity neurotrophin receptor stromal-epithelial expression pattern between benign and malignant human prostate. Urol Oncol 2012; 4:210-7. [PMID: 21227260 DOI: 10.1016/s1078-1439(98)00036-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/1998] [Indexed: 11/27/2022]
Abstract
Reduced expression of the low-affinity p75 neurotrophin receptor (p75(NTR)) occurs in prostate epithelial cells during malignant transformation. Recent studies indicating that the p75(NTR) can transduce signals that induce apoptosis suggest that diminished p75(NTR) in transformed prostate cells may contribute to immortalization. Mutations in the transmembrane domain of the p75(NTR) gene have been associated with decreased p75(NTR) protein expression and may block the ability of the p75(NTR) to induce apoptosis. Therefore, we used Western blot to analyze prostate cancer (PC) cell lines for p75(NTR) protein expression and gene single strand conformation polymorphism (SSCP) analysis and direct DNA sequencing to analyze mutations in the transmembrane domain of the p75(NTR). p75(NTR) Protein was present in all cell lines, and mutations in the p75(NTR) gene were not detected in cDNA derived from any cell line. To define the expression pattern of p75(NTR) in PCs in vivo, we used immunohistochemical techniques to examine tissue specimens from 20 benign, 19 malignant primary, and 14 metastatic prostate specimens. In benign prostate tissues, expression of p75(NTR) was universally detected in basal cells but not in secretory epithelial or stromal cells. In both primary and metastatic PC tissues, p75(NTR) immunoreactivity could not be detected in malignant prostate epithelial cells. However, in contrast to the benign prostate, p75(NTR) protein was expressed in stromal cells surrounding malignant epithelial cells. Stromal p75(NTR) expression was present in 84% (16 of 19) primary and in 86% (12 of 14) metastatic specimens. These data show that in the benign prostate p75(NTR) protein is expressed by basal cells and not stromal cells whereas in malignant prostate p75(NTR) protein is expressed by stromal cells but not prostatic carcinoma cells. Reversal of the p75(NTR) stromal-epithelial pattern of expression between benign and malignant prostate suggests that p75(NTR) may contribute to the development and maintenance of prostate cancer.
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Affiliation(s)
- C N Papandreou
- Genitourinary Oncology Research Laboratory, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York, NY, 10021, USA; Genitourinary Oncology Service, Division of Solid Tumor Oncology, Department of Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York, NY, 10021, USA
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19
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Yu H, Yang M, Wang Y, Xiao R, Zhou XF. p75NTR is mainly responsible for Aβ toxicity but not for its internalization: a primary study. Neurol Sci 2012; 33:1043-50. [PMID: 22183269 DOI: 10.1007/s10072-011-0892-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 12/07/2011] [Indexed: 12/13/2022]
Abstract
Accumulating evidence indicates that the intraneuronal accumulation of beta-amyloid peptide (Aβ) is earlier than the formation of extraneuronal amyloid plaque but the mechanism of the accumulation remains unclear. p75NTR is a receptor for Aβ and interacts with Aβ in vitro and in vivo but whether p75NTR mediates Aβ internalization and intraneuronal accumulation is not known. In this study, we aim to determine if p75NTR mediates Aβ internalization, which might provide new insights into Aβ metabolism and toxicity. FRET analysis in PC12 cells showed that internalized Aβ was close to p75NTR. Aβ1-42 could be internalized in PC12 cells in a concentration-dependent manner but the antibody to the p75NTR extracellular domain did not prevent its internalization. Aβ1-42 could also be internalized in mouse neonatal cortical neurons and the deletion of p75NTR in these neurons did not prevent its internalization but prevented Aβ neurotoxicity. Cholesterol at 10 μM significantly increased Aβ1-42 internalization in PC12 cells. Internalized Aβ1-42 is mainly co-localized with Beclin-1 (a biomarker of autophagosomes) but not with endosomal and lysomal markers. p75NTR may not play a main role in Aβ internalization at the concentrations tested but is responsible for Aβ induced toxicity in primary neurons. Internalized Aβ is mainly sorted to autophagosomes for metabolism.
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Affiliation(s)
- Huanling Yu
- Department of Human Physiology and Centre for Neuroscience, Flinders University, GPO Box 2100, Adelaide 5001, Australia.
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20
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Pryor S, McCaffrey G, Young LR, Grimes ML. NGF causes TrkA to specifically attract microtubules to lipid rafts. PLoS One 2012; 7:e35163. [PMID: 22496904 PMCID: PMC3319630 DOI: 10.1371/journal.pone.0035163] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/13/2012] [Indexed: 11/18/2022] Open
Abstract
Membrane protein sorting is mediated by interactions between proteins and lipids. One mechanism that contributes to sorting involves patches of lipids, termed lipid rafts, which are different from their surroundings in lipid and protein composition. Although the nerve growth factor (NGF) receptors, TrkA and p75(NTR) collaborate with each other at the plasma membrane to bind NGF, these two receptors are endocytosed separately and activate different cellular responses. We hypothesized that receptor localization in membrane rafts may play a role in endocytic sorting. TrkA and p75(NTR) both reside in detergent-resistant membranes (DRMs), yet they responded differently to a variety of conditions. The ganglioside, GM1, caused increased association of NGF, TrkA, and microtubules with DRMs, but a decrease in p75(NTR). When microtubules were induced to polymerize and attach to DRMs by in vitro reactions, TrkA, but not p75(NTR), was bound to microtubules in DRMs and in a detergent-resistant endosomal fraction. NGF enhanced the interaction between TrkA and microtubules in DRMs, yet tyrosine phosphorylated TrkA was entirely absent in DRMs under conditions where activated TrkA was detected in detergent-sensitive membranes and endosomes. These data indicate that TrkA and p75(NTR) partition into membrane rafts by different mechanisms, and that the fraction of TrkA that associates with DRMs is internalized but does not directly form signaling endosomes. Rather, by attracting microtubules to lipid rafts, TrkA may mediate other processes such as axon guidance.
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Affiliation(s)
- Shona Pryor
- Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand
| | - Gretchen McCaffrey
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
| | - Lindsay R. Young
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
- Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand
| | - Mark L. Grimes
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America
- Center for Structural and Functional Neuroscience, University of Montana, Missoula, Montana, United States of America
- * E-mail:
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21
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Iacaruso MF, Galli S, Martí M, Villalta JI, Estrin DA, Jares-Erijman EA, Pietrasanta LI. Structural Model for p75NTR–TrkA Intracellular Domain Interaction: A Combined FRET and Bioinformatics Study. J Mol Biol 2011; 414:681-98. [DOI: 10.1016/j.jmb.2011.09.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 09/09/2011] [Accepted: 09/14/2011] [Indexed: 11/16/2022]
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22
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The MYCN oncogene and differentiation in neuroblastoma. Semin Cancer Biol 2011; 21:256-66. [PMID: 21849159 DOI: 10.1016/j.semcancer.2011.08.001] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Accepted: 08/03/2011] [Indexed: 12/13/2022]
Abstract
Childhood neuroblastoma exhibits a heterogeneous clinical behavior ranging from low-risk tumors with the ability to spontaneously differentiate and regress, to high-risk tumors causing the highest number of cancer related deaths in infants. Amplification of the MYCN oncogene is one of the few prediction markers for adverse outcome. This gene encodes the MYCN transcriptional regulator predominantly expressed in the developing peripheral neural crest. MYCN is vital for proliferation, migration and stem cell homeostasis while decreased levels are associated with terminal neuronal differentiation. Interestingly, high-risk tumors without MYCN amplification frequently display increased c-MYC expression and/or activation of MYC signaling pathways. On the other hand, downregulation of MYCN leads to decreased proliferation and differentiation, emphasizing the importance of MYC signaling in neuroblastoma biology. Furthermore, expression of the neurotrophin receptor TrkA is associated with good prognosis, the ability to differentiate and spontaneous regression while expression of the related TrkB receptor is correlated with bad prognosis and MYCN amplification. Here we discuss the role of MYCN in neuroblastoma with a special focus on the contribution of elevated MYCN signaling for an aggressive and undifferentiated phenotype as well as the potential of using MYCN as a therapeutic target.
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23
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Skeldal S, Matusica D, Nykjaer A, Coulson EJ. Proteolytic processing of the p75 neurotrophin receptor: A prerequisite for signalling?: Neuronal life, growth and death signalling are crucially regulated by intra-membrane proteolysis and trafficking of p75(NTR). Bioessays 2011; 33:614-25. [PMID: 21717487 DOI: 10.1002/bies.201100036] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The common neurotrophin receptor (p75(NTR) ) regulates various functions in the developing and adult nervous system. Cell survival, cell death, axonal and growth cone retraction, and regulation of the cell cycle can be regulated by p75(NTR) -mediated signals following activation by either mature or pro-neurotrophins and in combination with various co-receptors, including Trk receptors and sortilin. Here, we review the known functions of p75(NTR) by cell type, receptor-ligand combination, and whether regulated intra-membrane proteolysis of p75(NTR) is required for signalling. We highlight that the generation of the intracellular domain fragment of p75(NTR) is associated with many of the receptor functions, regardless of its ligand and co-receptor interactions.
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Affiliation(s)
- Sune Skeldal
- The Lundbeck Foundation Research Center MIND, Department of Medical Biochemistry, Aarhus University, Aarhus, Denmark.
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24
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Camarena V, Kobayashi M, Kim JY, Roehm P, Perez R, Gardner J, Wilson AC, Mohr I, Chao MV. Nature and duration of growth factor signaling through receptor tyrosine kinases regulates HSV-1 latency in neurons. Cell Host Microbe 2011; 8:320-30. [PMID: 20951966 DOI: 10.1016/j.chom.2010.09.007] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2010] [Revised: 07/10/2010] [Accepted: 08/20/2010] [Indexed: 11/16/2022]
Abstract
Herpes simplex virus-1 (HSV-1) establishes life-long latency in peripheral neurons where productive replication is suppressed. While periodic reactivation results in virus production, the molecular basis of neuronal latency remains incompletely understood. Using a primary neuronal culture system of HSV-1 latency and reactivation, we show that continuous signaling through the phosphatidylinositol 3-kinase (PI3-K) pathway triggered by nerve growth factor (NGF)-binding to the TrkA receptor tyrosine kinase (RTK) is instrumental in maintaining latent HSV-1. The PI3-K p110α catalytic subunit, but not the β or δ isoforms, is specifically required to activate 3-phosphoinositide-dependent protein kinase-1 (PDK1) and sustain latency. Disrupting this pathway leads to virus reactivation. EGF and GDNF, two other growth factors capable of activating PI3-K and PDK1 but that differ from NGF in their ability to persistently activate Akt, do not fully support HSV-1 latency. Thus, the nature of RTK signaling is a critical host parameter that regulates the HSV-1 latent-lytic switch.
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Affiliation(s)
- Vladimir Camarena
- Molecular Neurobiology Program, Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
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25
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Formaggio E, Dalfini AC, Fazzini F, Fumagalli G, Chiamulera C. GABAergic neurons expressing p75 in rat substantia innominata and nucleus basalis. Mol Cell Neurosci 2011; 46:625-32. [PMID: 21238591 DOI: 10.1016/j.mcn.2011.01.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 01/01/2011] [Accepted: 01/03/2011] [Indexed: 11/17/2022] Open
Abstract
In vitro findings suggested a role for the p75 neurotrophin receptor in the maturation of GABAergic neurons residing in the basal forebrain (BF), a brain area known to have p75 expression only on cholinergic neurons. We document here the presence of GABAergic neurons which express p75 in the BF in vivo. Colocalization of p75 with the cholinergic marker choline-acetyltransferase (ChAT) and/or the GABAergic marker glutamic acid decarboxylase-67 (GAD67) was investigated in the BF at birth, at two weeks, and in adulthood. A subset of GAD67(+) neurons was p75(+) (p75(+)/GAD67(+)) but ChAT(-) in the substantia innominata and nucleus basalis magnocellularis at birth, whereas all p75(+)/GAD67(+) neurons were also ChAT(+) from two weeks onward. These phenotypic features suggest that a subpopulation of GABAergic neurons could be sensitive to neurotrophins during brain maturation. To unravel this issue, we then pursued a functional analysis by assessing p75 expression profile, and its modulation by nerve growth factor (NGF) or brain-derived neurotrophic factor (BDNF) in primary BF cell cultures. NGF increased p75 expression exclusively in cholinergic neurons, whereas BDNF induced p75 expression only in a subset of GABAergic neurons (p75(+)/GAD67(+)/ChAT(-)) through a p75- and tyrosine-kinase-dependent mechanism. The latter findings point to a selective role of BDNF in the induction of p75 expression in BF GABAergic neurons. Altogether these results confirm the role of neurotrophins in the developing and mature circuitry of GABAergic neurons in the BF regions.
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Affiliation(s)
- E Formaggio
- Department of Medicine and Public Health, Section of Pharmacology, University of Verona, P.le Scuro 10, 37134 Verona, Italy.
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Schecterson LC, Bothwell M. Neurotrophin receptors: Old friends with new partners. Dev Neurobiol 2010; 70:332-8. [PMID: 20186712 DOI: 10.1002/dneu.20767] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Neurotrophins are important regulators of embryonic development and adult function of most populations of neurons in vertebrate nervous systems. This signaling system regulates many diverse activities, including survival, axon outgrowth, and synaptic plasticity. In mammals, neurotrophin action is mediated by four receptors, p75(NTR), TrkA, TrkB, and TrkC. Although early studies viewed these receptors as solitary agents in the cells outer membrane, recent discoveries reveal that the cell outer membrane is a crowded and highly interactive neighborhood. Neurotrophin receptors partner with a diverse array of membrane proteins, dramatically expanding their functional repertoire. This review will focus on some of the most recent discoveries concerning the promiscuous partnering of neurotrophin receptors.
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Affiliation(s)
- Leslayann C Schecterson
- Department of Physiology & Biophysics, University of Washington, Seattle, Washington 98195, USA
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Chacón PJ, Arévalo MA, Tébar AR. NGF-activated protein tyrosine phosphatase 1B mediates the phosphorylation and degradation of I-kappa-Balpha coupled to NF-kappa-B activation, thereby controlling dendrite morphology. Mol Cell Neurosci 2010; 43:384-93. [PMID: 20123020 DOI: 10.1016/j.mcn.2010.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2009] [Revised: 01/03/2010] [Accepted: 01/21/2010] [Indexed: 02/07/2023] Open
Abstract
NGF diminishes dendrite complexity in cultured hippocampal neurons by decreasing the number of primary and secondary dendrites, while increasing the length of those that remain. The transduction pathway used by NGF to provoke dendrite elongation involves the activation of NF-kappa-B and the expression of the homologues of Enhancer-of-split 1 gene. Here, we define important steps that link NGF with NF-kappa-B activation, through the activity of protein tyrosine phosphatase 1B (PTP1B). Binding of NGF to p75(NTR) stimulates PTP1B activity, which can be blocked by either pharmacological inhibition of the phosphatase or by transfecting neurons with a dn PTP1B isoform, whereby NGF is no longer able to stimulate dendrite growth. Indeed, overexpressing PTP1B alone provoked dendrite growth and further studies revealed a role for the src kinase downstream of PTP1B. Again, loss of src activity largely cancelled out the capacity of NGF to promote dendrite growth, whereas overexpression of v-src in neurons was sufficient to promote dendrite growth. Finally, the NGF/p75(NTR)/PTP1B/src kinase pathway led to the tyrosine phosphorylation of I-kappa-Balpha prior to its degradation, an event that is necessary for NF-kappa-B activation. Indeed, the dendrite growth response to NGF was lost when neurons were transfected with a mutant form of I-kappa-Balpha that lacks tyr42. Thus, our data suggest that PTP1B fulfils a central role in the NGF signalling that controls dendrite patterning in hippocampal neurons.
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Affiliation(s)
- Pedro J Chacón
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER/CSIC), Av. Americo Vespucio s/n, Isla de la Cartuja, 41092 Seville, Spain
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Yoon C, Korade Z, Carter BD. Protein kinase A-induced phosphorylation of the p65 subunit of nuclear factor-kappaB promotes Schwann cell differentiation into a myelinating phenotype. J Neurosci 2008; 28:3738-46. [PMID: 18385332 PMCID: PMC6671072 DOI: 10.1523/jneurosci.4439-07.2008] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Revised: 02/29/2008] [Accepted: 03/01/2008] [Indexed: 11/21/2022] Open
Abstract
Axon-Schwann cell interactions are critical for myelin formation during peripheral nerve development and regeneration. Axonal contact promotes Schwann cell precursors to differentiate into a myelinating phenotype, and cAMP-elevating agents can mimic this; however, the mechanisms underlying this differentiation are poorly understood. We demonstrated previously that the transcription factor nuclear factor-kappaB (NF-kappaB) is required for myelin formation by Schwann cells (Nickols et al., 2003), although how it is activated during this process remained to be determined. Here, we report that culturing Schwann cells with sensory neurons results in the activation of cAMP-dependent protein kinase (PKA), and this kinase phosphorylates the p65 subunit of NF-kappaB at S276. The phosphorylation was also induced in cultured Schwann cells by treatment with forskolin, dibutyryl-cAMP, or by overexpression of a catalytic subunit of PKA, and this increased the transcriptional activity of NF-kappaB. In developing perinatal rat sciatic nerve, the kinetics of p65 phosphorylation at S276 paralleled that of PKA and NF-kappaB activation. To elucidate the role of p65 phosphorylation in myelin formation, we overexpressed an S276A mutant of p65 in cultured Schwann cells, which blocked PKA-mediated transcriptional activation of NF-kappaB. When the Schwann cells expressing the mutant were cocultured with sensory neurons, there was a 45% reduction in the number of myelinated fibers relative to controls, demonstrating a requirement for p65 phosphorylation by PKA during myelin formation.
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Affiliation(s)
- Choya Yoon
- Department of Biochemistry
- Center for Molecular Neuroscience, Vanderbilt University Medical School, Nashville, Tennessee 37232
| | - Zeljka Korade
- Department of Biochemistry
- Vanderbilt Kennedy Center, and
| | - Bruce D. Carter
- Department of Biochemistry
- Vanderbilt Kennedy Center, and
- Center for Molecular Neuroscience, Vanderbilt University Medical School, Nashville, Tennessee 37232
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Klinger MB, Girard B, Vizzard MA. p75NTR expression in rat urinary bladder sensory neurons and spinal cord with cyclophosphamide-induced cystitis. J Comp Neurol 2008; 507:1379-92. [PMID: 18189308 DOI: 10.1002/cne.21627] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A role for nerve growth factor (NGF) in contributing to increased voiding frequency and altered sensation from the urinary bladder has been suggested. Previous studies have examined the expression and regulation of tyrosine kinase receptors (Trks) in micturition reflexes with urinary bladder inflammation. The present studies examine the expression and regulation of another receptor known to bind NGF, p75(NTR), after various durations of bladder inflammation induced by cyclophosphamide (CYP). CYP-induced cystitis increased (P < or = 0.001) p75(NTR) expression in the superficial lateral and medial dorsal horn in L1-L2 and L6-S1 spinal segments. The number of p75(NTR)-immunoreactive (-IR) cells in the lumbosacral dorsal root ganglia (DRG) also increased (P < or = 0.05) with CYP-induced cystitis (acute, intermediate, and chronic). Quantitative, real-time polymerase chain reaction also demonstrated significant increases (P < or = 0.01) in p75(NTR) mRNA in DRG with intermediate and chronic CYP-induced cystitis. Retrograde dye-tracing techniques with Fastblue were used to identify presumptive bladder afferent cells in the lumbosacral DRG. In bladder afferent cells in DRG, p75(NTR)-IR was also increased (P < or = 0.01) with cystitis. In addition to increases in p75(NTR)-IR in DRG cell bodies, increases (P < or = 0.001) in pericellular (encircling DRG cells) p75(NTR)-IR in DRG also increased. Confocal analyses demonstrated that pericellular p75(NTR)-IR was not colocalized with the glial marker, glial fibrillary acidic protein (GFAP). These studies demonstrate that p75(NTR) expression in micturition reflexes is present constitutively and modified by bladder inflammation. The functional significance of p75(NTR) expression in micturition reflexes remains to be determined.
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Affiliation(s)
- Mary Beth Klinger
- Department of Anatomy and Neurobiology, University of Vermont College of Medicine, Burlington, Vermont 05405, USA
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30
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Tuffereau C, Schmidt K, Langevin C, Lafay F, Dechant G, Koltzenburg M. The rabies virus glycoprotein receptor p75NTR is not essential for rabies virus infection. J Virol 2007; 81:13622-30. [PMID: 17928338 PMCID: PMC2168826 DOI: 10.1128/jvi.02368-06] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2006] [Accepted: 10/01/2007] [Indexed: 12/25/2022] Open
Abstract
Rabies virus glycoprotein (RVG) is known to be the only factor that mediates rabies infection. The neurotrophin receptor (p75(NTR)), through its cysteine-rich domain 1, is a specific receptor for RVG and neutralizes virus infectivity, but its role in virus infection has remained obscure. We used adult mouse dorsal root ganglion (DRG) neurons as a model to study the role of p75(NTR) in RV infection of primary neurons. We show that RV infects around 20% of DRG neurons, of which more than 80% are p75(NTR) positive, have large diameters, and are capsaicin insensitive. Surprisingly, RV binding and infection are absent in about half of the p75(NTR)-expressing DRG neurons which have small diameters and are often capsaicin sensitive. This indicates that p75(NTR) is not sufficient to mediate RV interaction in sensory neurons. The rate and specificity of neural infection are unchanged in RV-infected p75(NTRExonIV-/-) mice that lack all extracellular receptor domains and in wild-type mice infected with two independent RV mutants that lack p75(NTR) binding. Accordingly, the mortality rate is unchanged in the absence of RV-p75(NTR) interaction. We conclude that although p75(NTR) is a receptor for soluble RVG in transfected cells of heterologous expression systems, an RVG-p75(NTR) interaction is not necessary for RV infection of primary neurons. This means that other receptors are required to mediate RV infection in vivo and in vitro.
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MESH Headings
- Animals
- Antigens, Viral/metabolism
- COS Cells
- Cells, Cultured
- Chlorocebus aethiops
- Female
- Ganglia, Spinal/cytology
- Ganglia, Spinal/virology
- Glycoproteins/metabolism
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Neurons/cytology
- Neurons/virology
- Rabies/virology
- Rabies virus/pathogenicity
- Receptors, Nerve Growth Factor/deficiency
- Receptors, Nerve Growth Factor/genetics
- Receptors, Nerve Growth Factor/metabolism
- Receptors, Virus/metabolism
- Viral Envelope Proteins/metabolism
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Affiliation(s)
- Christine Tuffereau
- Laboratoire de Virologie Moléculaire et Structurale, UMR 2472 CNRS-INRA, CNRS, 91198 Gif-sur-Yvette Cedex, France
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31
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Freund-Michel V, Frossard N. The nerve growth factor and its receptors in airway inflammatory diseases. Pharmacol Ther 2007; 117:52-76. [PMID: 17915332 DOI: 10.1016/j.pharmthera.2007.07.003] [Citation(s) in RCA: 125] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2007] [Accepted: 07/30/2007] [Indexed: 11/16/2022]
Abstract
The nerve growth factor (NGF) belongs to the neurotrophin family and induces its effects through activation of 2 distinct receptor types: the tropomyosin-related kinase A (TrkA) receptor, carrying an intrinsic tyrosine kinase activity in its intracellular domain, and the receptor p75 for neurotrophins (p75NTR), belonging to the death receptor family. Through activation of its TrkA receptor, NGF activates signalling pathways, including phospholipase Cgamma (PLCgamma), phosphatidyl-inositol 3-kinase (PI3K), the small G protein Ras, and mitogen-activated protein kinases (MAPK). Through its p75NTR receptor, NGF activates proapoptotic signalling pathways including the MAPK c-Jun N-terminal kinase (JNK), ceramides, and the small G protein Rac, but also activates pathways promoting cell survival through the transcription factor nuclear factor-kappaB (NF-kappaB). NGF was first described by Rita Levi-Montalcini and collaborators as an important factor involved in nerve differentiation and survival. Another role for NGF has since been established in inflammation, in particular of the airways, with increased NGF levels in chronic inflammatory diseases. In this review, we will first describe NGF structure and synthesis and NGF receptors and their signalling pathways. We will then provide information about NGF in the airways, describing its expression and regulation, as well as pointing out its potential role in inflammation, hyperresponsiveness, and remodelling process observed in airway inflammatory diseases, in particular in asthma.
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Affiliation(s)
- V Freund-Michel
- EA 3771 Inflammation and Environment in Asthma, University Louis Pasteur-Strasbourg I, Faculty of Pharmacy, Illkirch, France.
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32
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Wehrman T, He X, Raab B, Dukipatti A, Blau H, Garcia KC. Structural and mechanistic insights into nerve growth factor interactions with the TrkA and p75 receptors. Neuron 2007; 53:25-38. [PMID: 17196528 DOI: 10.1016/j.neuron.2006.09.034] [Citation(s) in RCA: 217] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2006] [Revised: 08/15/2006] [Accepted: 09/22/2006] [Indexed: 12/23/2022]
Abstract
Nerve growth factor engages two structurally distinct transmembrane receptors, TrkA and p75, which have been proposed to create a "high-affinity" NGF binding site through formation of a ternary TrkA/NGF/p75 complex. To define a structural basis for the high-affinity site, we have determined the three-dimensional structure of a complete extracellular domain of TrkA complexed with NGF. The complex reveals a crab-shaped homodimeric TrkA structure, but a mechanism for p75 coordination is not obvious. We investigated the heterodimerization of membrane-bound TrkA and p75, on intact mammalian cells, using a beta-gal protein-protein interaction system. We find that NGF dimerizes TrkA and that p75 exists on the cell surface as a preformed oligomer that is not dissociated by NGF. We find no evidence for a direct TrkA/p75 interaction. We propose that TrkA and p75 likely communicate through convergence of downstream signaling pathways and/or shared adaptor molecules, rather than through direct extracellular interactions.
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Affiliation(s)
- Tom Wehrman
- Baxter Laboratory for Genetic Pharmacology, Department of Microbiology and Immunology, The Stem Cell Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
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33
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Domeniconi M, Hempstead BL, Chao MV. Pro-NGF secreted by astrocytes promotes motor neuron cell death. Mol Cell Neurosci 2006; 34:271-9. [PMID: 17188890 PMCID: PMC2570110 DOI: 10.1016/j.mcn.2006.11.005] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 10/23/2006] [Accepted: 11/10/2006] [Indexed: 11/25/2022] Open
Abstract
It is well established that motor neurons depend for their survival on many trophic factors. In this study, we show that the precursor form of NGF (pro-NGF) can induce the death of motor neurons via engagement of the p75 neurotrophin receptor. The pro-apoptotic activity was dependent upon the presence of sortilin, a p75 co-receptor expressed on motor neurons. One potential source of pro-NGF is reactive astrocytes, which up-regulate the levels of pro-NGF in response to peroxynitrite, an oxidant and producer of free radicals. Indeed, motor neuron viability was sensitive to conditioned media from cultured astrocytes treated with peroxynitrite and this effect could be reversed using a specific antibody against the pro-domain of pro-NGF. These results are consistent with a role for activated astrocytes and pro-NGF in the induction of motor neuron death and suggest a possible therapeutic target for the treatment of motor neuron disease.
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Affiliation(s)
- Marco Domeniconi
- Molecular Neurobiology Program, Skirball Institute of Biomolecular Medicine, Department of Cell Biology, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA
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34
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Abstract
Regulation of cell survival decisions and neuronal plasticity by neurotrophins are mediated by two classes of receptors, Trks (tropomyosin receptor kinases) and p75, the first discovered member of the tumour necrosis factor receptor superfamily. The p75 receptor participates with the TrkA receptor in the formation of high-affinity nerve growth factor-binding sites to promote survival under limiting concentrations of neurotrophins. Activation of Trk receptors leads to increased phosphorylation of Shc (Src homology and collagen homology), phospholipase C-gamma and novel adaptor molecules, such as the ARMS (ankyrin-rich membrane spanning)/Kidins220 protein. Small ligands that interact with G-protein-coupled receptors can also activate Trk receptor kinase activity. Transactivation of Trk receptors and their downstream signalling pathways raise the possibility of using small molecules to elicit neuroprotective effects for the treatment of neurodegenerative diseases. Like amyloid precursor protein and Notch, p75 is a substrate for gamma-secretase cleavage. The p75 receptor undergoes an alpha-secretase-mediated release of the extracellular domain followed by a gamma-secretase-mediated intramembrane cleavage. Cleavage of p75 may represent a general mechanism for transmitting signals as an independent receptor and as a co-receptor for other signalling systems.
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Affiliation(s)
- N Zampieri
- Molecular Neurobiology Program, Skirball Institute of Biomolecular Medicine, Departments of Cell Biology, Physiology and Neuroscience, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA
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35
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Arevalo MA, Rodríguez-Tébar A. Activation of casein kinase II and inhibition of phosphatase and tensin homologue deleted on chromosome 10 phosphatase by nerve growth factor/p75NTR inhibit glycogen synthase kinase-3beta and stimulate axonal growth. Mol Biol Cell 2006; 17:3369-77. [PMID: 16723502 PMCID: PMC1525228 DOI: 10.1091/mbc.e05-12-1144] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2005] [Revised: 05/01/2006] [Accepted: 05/11/2006] [Indexed: 12/16/2022] Open
Abstract
Axonal elongation and guidance are controlled by extracellular factors such as the neurotrophins. Indeed, nerve growth factor (NGF) seems to promote axon growth through binding to its p75NTR receptor and inactivating RhoA. Furthermore, the local inhibition of glycogen synthase kinase (GSK)-3beta by NGF also favors microtubule polymerization and axon extension. Inactivation of GSK-3beta may be due to the NGF/TrkA-mediated activation of phosphatidylinositol-3 kinase (PI-3 kinase), which increases the levels of phosphatydilinositol 3-phosphate [PI3P]. However, we show here that NGF may inactivate GSK-3beta through an alternative mechanism. In cultured hippocampal neurons, the capacity of NGF to promote axon elongation is mostly mediated by p75NTR, and the activation of this pathway leads to the inactivation of GSK-3beta. However, the signaling pathway triggered by NGF/p75NTR acts through casein kinase II (CK2). NGF/p75NTR-activated CK2 phosphorylates the phosphatase and tensin homologue deleted on chromosome 10 (PTEN), thus rendering this phosphatase inactive. Like activation of the PI-3 kinase, PTEN inactivation allows PI3P levels to increase, thus favoring GSK-3beta inactivation and axon outgrowth. This newly disclosed mechanism may help to extend the repertoire of pharmacological agents that activate CK2 or that inhibit PTEN to stimulate axon regeneration after trauma or disease.
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Affiliation(s)
- María-Angeles Arevalo
- Instituto Cajal de Neurobiología, Consejo Superior de Investigaciones Cientificas, E28002 Madrid, Spain
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36
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Singh B, Henneberger C, Betances D, Arevalo MA, Rodríguez-Tébar A, Meier JC, Grantyn R. Altered balance of glutamatergic/GABAergic synaptic input and associated changes in dendrite morphology after BDNF expression in BDNF-deficient hippocampal neurons. J Neurosci 2006; 26:7189-200. [PMID: 16822976 PMCID: PMC6673958 DOI: 10.1523/jneurosci.5474-05.2006] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cultured neurons from bdnf-/- mice display reduced densities of synaptic terminals, although in vivo these deficits are small or absent. Here we aimed at clarifying the local responses to postsynaptic brain-derived neurotrophic factor (BDNF). To this end, solitary enhanced green fluorescent protein (EGFP)-labeled hippocampal neurons from bdnf-/- mice were compared with bdnf-/- neurons after transfection with BDNF, bdnf-/- neurons after transient exposure to exogenous BDNF, and bdnf+/+ neurons in wild-type cultures. Synapse development was evaluated on the basis of presynaptic immunofluorescence and whole-cell patch-clamp recording of miniature postsynaptic currents. It was found that neurons expressing BDNF::EGFP for at least 16 h attracted a larger number of synaptic terminals than BDNF-deficient control neurons. Transfected BDNF formed clusters in the vicinity of glutamatergic terminals and produced a stronger upregulation of synaptic terminal numbers than high levels of ambient BDNF. Glutamatergic and GABAergic synapses reacted differently to postsynaptic BDNF: glutamatergic input increased, whereas GABAergic input decreased. BDNF::EGFP-expressing neurons also differed from BDNF-deficient neurons in their dendrite morphology: they exhibited weaker dendrite elongation and stronger dendrite initiation. The upregulation of glutamatergic synaptic input and the BDNF-induced downregulation of GABAergic synaptic terminal numbers by postsynaptic BDNF depended on tyrosine receptor kinase B activity, as deduced from the blocking effects of K252a. The suppression of dendrite elongation was also prevented by block of tyrosine receptor kinase B but required, in addition, glutamate receptor activity. Dendritic length decreased with the number of glutamatergic contacts. These results illuminate the role of BDNF as a retrograde synaptic regulator of synapse development and the dependence of dendrite elongation on glutamatergic input.
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Affiliation(s)
- B Singh
- Developmental Physiology Group, Johannes Mueller Institute for Neurophysiology, University Medical School (Charité) of the Humboldt University, D-10117 Berlin, Germany
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37
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Rogers ML, Atmosukarto I, Berhanu DA, Matusica D, Macardle P, Rush RA. Functional monoclonal antibodies to p75 neurotrophin receptor raised in knockout mice. J Neurosci Methods 2006; 158:109-20. [PMID: 16828166 DOI: 10.1016/j.jneumeth.2006.05.022] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 05/16/2006] [Accepted: 05/24/2006] [Indexed: 10/24/2022]
Abstract
In this study, p75NTREXONIII knockout mice were used as immune-naive hosts to produce functional antibodies to human p75NTR. Three monoclonal antibodies were produced and named MLR1, MLR2 and MLR3, and isotyped as IgG1, IgG2a and IgG2a, respectively. MLR1 and MLR2 bound to human p75NTR with higher affinity than the well-characterized ME20.4 in ELISA and also recognized p75NTR present on neurons in both rat and mouse. MLR1 and MLR2 bound to nerves known to express p75NTR following injection into Balb/C mice but not p75NTREXONIII knockout mice, indicating the antibodies are directed against the ligand binding extracellular region absent in knockout mice. Both MLR1 and MLR2 partially blocked NGF induced cell death in a mouse cell-line that expresses p75NTR but not TrKA. Importantly, intracerebroventricular injections indicated MLR2 was internalized within the cell bodies of mouse basal forebrain neurons, further demonstrating that this antibody is biologically active.
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Affiliation(s)
- Mary-Louise Rogers
- Centre for Neuroscience, Department of Human Physiology, School of Medicine, Flinders University, South Australia, Australia.
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38
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Salama-Cohen P, Arévalo MA, Grantyn R, Rodríguez-Tébar A. Notch and NGF/p75NTR control dendrite morphology and the balance of excitatory/inhibitory synaptic input to hippocampal neurones through Neurogenin 3. J Neurochem 2006; 97:1269-78. [PMID: 16539652 DOI: 10.1111/j.1471-4159.2006.03783.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We have previously shown that dendrite morphology of cultured hippocampal neurones is controlled by Notch receptor activation or binding of nerve growth factor (NGF) to its low affinity receptor p75NTR, i.e. processes that up-regulate the expression of the Homologue of enhancer of split 1 and 5. Thus, the increased expression of these genes decreases the number of dendrites, whereas abrogation of Homologue of enhancer of split 1/5 activity stimulates the outgrowth of new dendrites. Here, we show that Neurogenin 3 is a proneural gene that is negatively regulated by Homologue of enhancer of split 1/5. It also influences dendrite morphology. Hence, a deficit of Notch or NGF/p75NTR activation can lead to the production of high levels of Neurogenin 3, which stimulates the outgrowth of new dendrites. Conversely, activation of either Notch or p75NTR depressed Neurogenin 3 expression, which not only decreased the number of dendrites but also favoured inhibitory (GABAergic) synaptogenesis, thereby diminishing the ratios of excitatory/inhibitory inputs. NGF also augmented the levels of mRNA encoding the vesicular inhibitory amino acid transporter, but it did not affect the fraction of GAD65/67-positive neurones. Conversely, overexpression of Neurogenin 3 largely reduced the number of inhibitory synaptic contacts and, consequently, produced a strong increase in the ratios of excitatory/inhibitory synaptic terminals. Our results reveal a hitherto unknown contribution of NGF/p75NTR to dendritic and synaptic plasticity through Neurogenin 3 signalling.
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Faure C, Chalazonitis A, Rhéaume C, Bouchard G, Sampathkumar SG, Yarema KJ, Gershon MD. Gangliogenesis in the enteric nervous system: Roles of the polysialylation of the neural cell adhesion molecule and its regulation by bone morphogenetic protein-4. Dev Dyn 2006; 236:44-59. [PMID: 16958105 DOI: 10.1002/dvdy.20943] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The neural crest-derived cells that colonize the fetal bowel become patterned into two ganglionated plexuses. The hypothesis that bone morphogenetic proteins (BMPs) promote ganglionation by regulating neural cell adhesion molecule (NCAM) polysialylation was tested. Transcripts encoding the sialyltransferases, ST8Sia IV (PST) and ST8Sia II (STX), which polysialylate NCAM, were detectable in fetal rat gut by E12 but were downregulated postnatally. PSA-NCAM-immunoreactive neuron numbers, but not those of NCAM, were developmentally regulated similarly. Circular smooth muscle was transiently (E16-20) PSA-NCAM-immunoreactive when it is traversed by migrating precursors of submucosal neurons. Neurons developing in vitro from crest-derived cells immunoselected at E12 with antibodies to p75(NTR) expressed NCAM and PSA-NCAM. BMP-4 promoted neuronal NCAM polysialylation and clustering. N-butanoylmannosamine, which blocks NCAM polysialylation, but not N-propanoylmannosamine, which does not, interfered with BMP-4-induced neuronal clustering. Observations suggest that BMP signaling enhances NCAM polysialylation, which allows precursors to migrate and form ganglionic aggregates during the remodeling of the developing ENS.
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Affiliation(s)
- Christophe Faure
- Division of Gastroenterology, Sainte-Justine Hospital Research Center, University of Montreal, Montreal, Quebec, Canada.
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40
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Susen K, Blöchl A. Low concentrations of aggregated β-amyloid induce neurite formation via the neurotrophin receptor p75. J Mol Med (Berl) 2005; 83:720-35. [PMID: 16001231 DOI: 10.1007/s00109-005-0671-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2005] [Accepted: 04/04/2005] [Indexed: 02/06/2023]
Abstract
Aggregated beta-amyloid (Abeta) binds to the neurotrophin receptor p75 and induces signaling. We examined this signaling process in different cell lines which express p75 either naturally (Schwannoma RN22 cells) or which are stably transfected with wild-type p75 (MDCKwt and PCNA cells) or with a truncated form of p75 comprising only extracellular and transmembrane domains (MDCKtm cells). While Abeta in higher concentrations (10-100 microM) is known to cause apoptosis via p75, our experiments focused on the effects of low concentrations of Abeta (25 nM) which may occur in early stages of Alzheimer disease. Application of Abeta caused tyrosine phosphorylation of wild-type p75 and induced the Ras-ERK pathway as has been reported for nerve growth factor (NGF). Since Ras activation and ERK phosphorylation (via MEK) could not be observed in MDCKtm cells and since they were clearly reduced in cells transfected with a p75 antisense construct, these effects should have been mediated by p75. Abeta also induced Ras and ERK activation in cerebellar neurons of 2-day-old rats which express p75 at that developmental stage but not TrkA; other Trk receptors were inhibited by K252a. In these neurons, Abeta led to quick formation, branching and elongation of processes. But while NGF distinctly promoted neurite branching and elongation, Abeta was less effective in neurite elongation and counts of small processes and of growth cones remained clearly elevated after 24-h stimulation; these peculiarities might be linked to aberrant neuronal connections reported for an animal model of Alzheimer disease. Essentially, the observed effects were mediated by interaction of Abeta and p75.
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Affiliation(s)
- K Susen
- Ruhr-Universität Bochum, Fakultät Chemie, Biochemie II, 44790 Bochum, Germany
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41
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Williams G, Williams EJ, Maison P, Pangalos MN, Walsh FS, Doherty P. Overcoming the inhibitors of myelin with a novel neurotrophin strategy. J Biol Chem 2004; 280:5862-9. [PMID: 15572360 DOI: 10.1074/jbc.m411121200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myelin inhibitors activate a p75(NTR)-dependent signaling cascade in neurons that not only inhibits axonal growth but also prevents neurotrophins (NT) from stimulating growth. Most intriguingly, in addition to Trk receptors, neurotrophins also bind to p75(NTR). We have designed a "mini-neurotrophin" called B(AG) to activate TrkB in the absence of p75(NTR) binding. We find that B(AG) is as effective as the natural TrkB ligands (brain-derived neurotrophic factor (BDNF) and NT-4) at promoting neurite outgrowth from cerebellar neurons. Furthermore, the neurite outgrowth responses stimulated by BDNF and B(AG) are inhibited by a common set of reagents, including the Trk receptor inhibitor K252a, as well as protein kinase A and phosphoinositide 3-kinase inhibitors. However, in contrast to BDNF, B(AG) promotes growth in the presence of a myelin inhibitor or when antibodies directly activate the p75(NTR) inhibitory pathway. On the basis of this observation, we postulated that the binding of BDNF to the p75(NTR) might compromise the ability of BDNF to stimulate neurite outgrowth in an inhibitory environment. To test this, we used NGF, and an NGF-derived peptide, to compete for the BDNF/p75(NTR) interaction; remarkably, in the presence of either agent, BDNF acquired the ability to promote neurite outgrowth in the presence of a myelin inhibitor. The data suggest that in an inhibitory environment, the BDNF/p75(NTR) interaction compromises regeneration. Agents that activate Trk receptors in the absence of p75(NTR) binding, or agents that inhibit neurotrophin/p75(NTR) binding, might therefore be better therapeutic candidates than neurotrophins.
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Affiliation(s)
- Gareth Williams
- The Wolfson Centre for Age-related Diseases, King's College London, London SE1 1UL, UK
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42
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Chang MS, Arevalo JC, Chao MV. Ternary complex with Trk, p75, and an ankyrin-rich membrane spanning protein. J Neurosci Res 2004; 78:186-92. [PMID: 15378608 DOI: 10.1002/jnr.20262] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Neurotrophins play many critical roles in regulating neuronal plasticity, survival, and differentiation in the nervous system. Neurotrophins recognize two different receptors, the Trk receptor tyrosine kinase and the p75 neurotrophin receptor, which are associated closely. Several adaptor proteins are associated with each receptor. An ankyrin-rich membrane spanning protein (ARMS), originally identified as a substrate for protein kinase D (Kidins220) and as a p75 interacting protein, serves as a novel downstream target of Trk receptor tyrosine kinases. Kidins220/ARMS is co-expressed frequently with Trk and p75 and represents the only membrane-associated protein known to interact with both receptors. We report here that a ternary complex can be formed between Trk, p75, and Kidins220/ARMS. The extracellular domains of the TrkA and the p75 receptors are necessary for their association, whereas the juxtamembrane region of p75 was responsible for the interaction with Kidins220/ARMS. Interestingly, increasing the level of Kidins220/ARMS expression resulted in a decreased association of TrkA with p75. These findings thus suggest that Kidins220/ARMS plays an important role in regulating interactions between Trk and p75 neurotrophin receptors.
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Affiliation(s)
- Mi-Sook Chang
- Molecular Neurobiology Program, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, USA.
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43
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Abstract
Nerve growth factor (NGF) initially interested neurobiologists because of its effects in the developing nervous system. It is now clear that NGF functions throughout the life of the animal with a wide repertoire of actions. In the sensory nervous system it primarily influences the structure and function of nociceptors. Here, we provide a brief review of these actions and raise the overriding biological questions of why these multiple actions occur and how they are carried out.
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MESH Headings
- Afferent Pathways/cytology
- Afferent Pathways/growth & development
- Afferent Pathways/metabolism
- Animals
- Cell Differentiation/drug effects
- Cell Differentiation/physiology
- Ganglia, Spinal/cytology
- Ganglia, Spinal/growth & development
- Ganglia, Spinal/metabolism
- Humans
- Nerve Growth Factor/metabolism
- Nerve Growth Factor/pharmacology
- Neurons, Afferent/cytology
- Neurons, Afferent/drug effects
- Neurons, Afferent/metabolism
- Nociceptors/cytology
- Nociceptors/growth & development
- Nociceptors/metabolism
- Phenotype
- Receptor, trkA/drug effects
- Receptor, trkA/metabolism
- Receptors, Drug/drug effects
- Receptors, Drug/metabolism
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Affiliation(s)
- Jeffrey C Petruska
- Department of Neurobiology and Behavior, Stony Brook, NY 11794-5230, USA
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45
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Dahlin LB, Brandt J. Basic science of peripheral nerve repair: Wallerian degeneration/growth cones. ACTA ACUST UNITED AC 2004. [DOI: 10.1053/j.oto.2004.06.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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46
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Murray SS, Perez P, Lee R, Hempstead BL, Chao MV. A novel p75 neurotrophin receptor-related protein, NRH2, regulates nerve growth factor binding to the TrkA receptor. J Neurosci 2004; 24:2742-9. [PMID: 15028767 PMCID: PMC6729530 DOI: 10.1523/jneurosci.3960-03.2004] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Nerve growth factor (NGF) functions as a ligand for two receptors, the TrkA tyrosine kinase receptor and the p75 neurotrophin receptor (p75NTR). The Ig-like domains of Trk receptors and the cysteine-rich repeats of p75NTR are involved in binding to the neurotrophins. Recently, a closely related gene to p75NTR called neurotrophin receptor homolog-2 (NRH2) was identified; however, the function of NRH2 and its relevance to neurotrophin signaling are unclear. NRH2 contains a similar transmembrane and intracellular domain as p75NTR but lacks the characteristic cysteine-rich repeats in the extracellular domain. Here we show that NRH2 is expressed in several neuronal populations that also express p75NTR and Trk receptors. NRH2 does not bind to NGF; however, coimmunoprecipitation experiments demonstrate that NRH2 is capable of interacting with TrkA receptors. Coexpression of NRH2 with TrkA receptors resulted in the formation of high-affinity binding sites for NGF. These results indicate that a transmembrane protein related to p75NTR is capable of modulating Trk receptor binding properties.
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Affiliation(s)
- Simon S Murray
- Skirball Institute of Bimolecular Medicine, New York University School of Medicine, New York, New York 10016, USA.
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47
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Epa WR, Markovska K, Barrett GL. The p75 neurotrophin receptor enhances TrkA signalling by binding to Shc and augmenting its phosphorylation. J Neurochem 2004; 89:344-53. [PMID: 15056278 DOI: 10.1111/j.1471-4159.2004.02344.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nerve growth factor (NGF) is an important neuronal survival factor, especially during development. Optimal sensitivity of the survival response to NGF requires the presence of TrkA and the p75 neurotrophin receptor, p75(NTR). Signalling pathways used by TrkA are well established, but the mechanisms by which p75(NTR) enhances NGF signalling remain far from clear. A prevalent view is that p75(NTR) and TrkA combine to form a high-affinity receptor, but definitive evidence for this is still lacking. We therefore investigated the possibility that p75(NTR) and TrkA interact via their signal transduction pathways. Using antisense techniques to down-regulate p75(NTR) and TrkA, we found that p75(NTR) specifically enhanced phosphorylation of the 46- and 52-kDa isoforms of Shc during nerve growth factor-induced TrkA activation. p75(NTR) did not enhance tyrosine phosphorylation of other TrkA substrates. Serine phosphorylation of Akt, downstream of Shc activation, was also p75(NTR)-dependent. We consistently detected co-immunoprecipitation of p75(NTR) and Shc. These data indicate that p75(NTR) interacts with Shc physically, via a binding interaction, and functionally, by assisting its phosphorylation. Whilst providing evidence that p75(NTR) augments TrkA signal transduction, these results do not preclude the presence of a p75(NTR)-TrkA high-affinity NGF receptor.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Adaptor Proteins, Vesicular Transport/metabolism
- Animals
- Cell Differentiation/physiology
- Cell Survival/drug effects
- Cell Survival/physiology
- Dose-Response Relationship, Drug
- Down-Regulation/drug effects
- Down-Regulation/genetics
- Nerve Growth Factor/pharmacology
- Neurons/drug effects
- Neurons/metabolism
- Oligonucleotides, Antisense/drug effects
- PC12 Cells
- Phosphorylation
- Precipitin Tests
- Protein Serine-Threonine Kinases
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-akt
- Rats
- Receptor, Nerve Growth Factor
- Receptor, trkA/metabolism
- Receptors, Nerve Growth Factor/antagonists & inhibitors
- Receptors, Nerve Growth Factor/genetics
- Receptors, Nerve Growth Factor/metabolism
- Shc Signaling Adaptor Proteins
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Src Homology 2 Domain-Containing, Transforming Protein 1
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Affiliation(s)
- W Ruwan Epa
- Physiology Department, University of Melbourne, Parkville, Victoria, Australia
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Colquhoun A, Lawrance GM, Shamovsky IL, Riopelle RJ, Ross GM. Differential Activity of the Nerve Growth Factor (NGF) Antagonist PD90780 [7-(Benzolylamino)-4,9-dihydro-4-methyl-9-oxo-pyrazolo[5,1-b]quinazoline-2-carboxylic Acid] Suggests Altered NGF-p75NTRInteractions in the Presence of TrkA. J Pharmacol Exp Ther 2004; 310:505-11. [PMID: 15051797 DOI: 10.1124/jpet.104.066225] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The neurotrophin nerve growth factor (NGF) binds to two receptor types: the tyrosine kinase receptor TrkA and the common neurotrophin receptor p75(NTR). Although many of the biological effects of NGF (such as neuronal growth and survival) are associated with TrkA activation, p75(NTR) also contributes to these activities by enhancing the action of TrkA when receptors are coexpressed. The NGF antagonist PD90780 [7-(benzolylamino)-4,9-dihydro-4-methyl-9-oxo-pyrazolo[5,1-b]quinazoline-2-carboxylic acid] interacts with NGF, preventing its binding to p75(NTR). In this study, the actions of this compound are further explored, and it is found that PD90780 is not able to inhibit the binding of either brain-derived neurotrophic factor or neurotrophin-3 to p75(NTR), consistent with the direct interactions of the antagonist with NGF. In addition, we demonstrate that the ability of PD90780 to inhibit NGF-p75(NTR) interactions is lower when receptors are coexpressed, compared with when p75(NTR) is the only neurotrophin receptor expressed. These results suggest that the interaction between NGF and the p75(NTR) receptor is altered when TrkA is coexpressed. This alteration can be exploited in the development of antagonists that will selectively inhibit the pro-apoptotic actions of p75(NTR) when expressed in the absence of TrkA, although having less effect on the pro-survival effects of p75(NTR) mediated by enhanced TrkA activation.
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Affiliation(s)
- Amy Colquhoun
- Department of Physiology, Queen's University, Kingston, Ontario, Canada K7L 3N6
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Neurotrophins elevate cAMP to reach a threshold required to overcome inhibition by MAG through extracellular signal-regulated kinase-dependent inhibition of phosphodiesterase. J Neurosci 2004. [PMID: 14684879 DOI: 10.1523/jneurosci.23-37-11770.2003] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Inhibitors of regeneration in myelin, such as myelin-associated glycoprotein (MAG), play an important role in preventing regeneration after CNS injury. Elevation of cAMP, either with dibutyryl-cAMP (db-cAMP) or by priming with a variety of neurotrophins, overcomes inhibition by MAG and myelin. However, activation of cAMP is not generally regarded as a signaling pathway for neurotrophins. Here we show that the NGF-like neurotrophins overcome inhibition by MAG by activating tyrosine kinase receptors. We also show that activation of extracellular signal-regulated kinase (Erk) by BDNF is required to overcome inhibition by MAG, and that activated Erk transiently inhibits phosphodiesterase 4 (PDE4), the enzyme that hydrolyzes cAMP. Inhibition of PDE4 then allows cAMP to increase and so initiates the pathway to overcome inhibition. Furthermore, we also show that basal levels of Erk activation and basal cAMP levels contribute to the effects of db-cAMP by pushing the combined levels of cAMP above a threshold required to overcome inhibition. Together, these results not only show how NGF-like neurotrophins can elevate cAMP and overcome inhibition but also point to a novel mechanism of cross talk in neurons from the Erk to the cAMP signaling pathways.
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50
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Proteolytic processing of the p75 neurotrophin receptor and two homologs generates C-terminal fragments with signaling capability. J Neurosci 2003. [PMID: 12843241 DOI: 10.1523/jneurosci.23-13-05425.2003] [Citation(s) in RCA: 192] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The 75 kDa neurotrophin receptor (p75NTR) and two neurotrophin receptor homologs (NRH1, NRH2) constitute a subfamily of the nerve growth factor/tumor necrosis factor receptor superfamily. NRH1 coexists with p75NTR in fish, amphibians, and birds but is absent in mammals, whereas NRH2 exists only in mammals. Unlike p75NTR and NRH1, NRH2 lacks a canonical extracellular ligand binding domain. The similarity of NRH2 to the product of metalloproteinase cleavage of p75NTR prompted us to examine the cleavage of p75NTR in greater detail. p75NTR, NRH1, and NRH2 undergo multiple proteolytic cleavages that ultimately release cytoplasmic fragments. For p75NTR, cleavage in the extracellular domain by a PMA-inducible membrane metalloproteinase is followed by cleavage within or near the transmembrane domain, releasing the intracellular domain into the cytoplasm. This processing resembles the alpha- and gamma-secretase-mediated processing of beta-amyloid precursor protein and the similar processing of Notch. Although neurotrophins did not regulate p75NTR processing, the alpha- and gamma-secretase-mediated cleavage of p75 is modulated by receptor tyrosine kinases (Trks) TrkA and TrkB but not TrkC. Surprisingly, although NRH1 and NRH2 also undergo proteolytic cytoplasmic release of intracellular domains, a different protease mediates the cleavage. Furthermore, whereas the p75NTR soluble intracellular domain accumulates only in the presence of proteasome inhibitors, the equivalent fragment of NRH2 is stable and localizes in the nucleus. Because soluble intracellular domains of p75NTR and NRH2 were found to activate NF-kappaB in concert with TNF receptor associated factor 6 (TRAF6), we propose that cleavage of these proteins may serve conserved cytoplasmic and nuclear signaling functions through distinct proteases.
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