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Kirstein M, Cambrils A, Segarra A, Melero A, Varea E. Cholinergic Senescence in the Ts65Dn Mouse Model for Down Syndrome. Neurochem Res 2022; 47:3076-3092. [PMID: 35767135 PMCID: PMC9470680 DOI: 10.1007/s11064-022-03659-0] [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: 01/19/2022] [Revised: 06/08/2022] [Accepted: 06/14/2022] [Indexed: 11/29/2022]
Abstract
Down syndrome (DS) induces a variable phenotype including intellectual disabilities and early development of Alzheimer’s disease (AD). Moreover, individuals with DS display accelerated aging that affects diverse organs, among them the brain. The Ts65Dn mouse is the most widely used model to study DS. Progressive loss of cholinergic neurons is one of the hallmarks of AD present in DS and in the Ts65Dn model. In this study, we quantify the number of cholinergic neurons in control and Ts65Dn mice, observing a general reduction in their number with age but in particular, a greater loss in old Ts65Dn mice. Increased expression of the m1 muscarinic receptor in the hippocampus counteracts this loss. Cholinergic neurons in the Ts65Dn mice display overexpression of the early expression gene c-fos and an increase in the expression of β-galactosidase, a marker of senescence. A possible mechanism for senescence induction could be phosphorylation of the transcription factor FOXO1 and its retention in the cytoplasm, which we are able to confirm in the Ts65Dn model. In our study, using Ts65Dn mice, we observe increased cholinergic activity, which induces a process of early senescence that culminates in the loss of these neurons.
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Affiliation(s)
- Martina Kirstein
- Cell Biology Department, Universitat de València, Dr. Moliner, 50, Burjassot, 46100, València, Spain
| | - Alba Cambrils
- Cell Biology Department, Universitat de València, Dr. Moliner, 50, Burjassot, 46100, València, Spain
| | - Ana Segarra
- Cell Biology Department, Universitat de València, Dr. Moliner, 50, Burjassot, 46100, València, Spain
| | - Ana Melero
- Cell Biology Department, Universitat de València, Dr. Moliner, 50, Burjassot, 46100, València, Spain
| | - Emilio Varea
- Cell Biology Department, Universitat de València, Dr. Moliner, 50, Burjassot, 46100, València, Spain.
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2
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Liang SY, Wang ZT, Tan L, Yu JT. Tau Toxicity in Neurodegeneration. Mol Neurobiol 2022; 59:3617-3634. [PMID: 35359226 DOI: 10.1007/s12035-022-02809-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 03/20/2022] [Indexed: 12/22/2022]
Abstract
Tau is a microtubule-associated protein widely distributed in the central nervous system (CNS). The main function of tau is to promote the assembly of microtubules and stabilize their structure. After a long period of research on neurodegenerative diseases, the function and dysfunction of the microtubule-associated protein tau in neurodegenerative diseases and tau neurotoxicity have attracted increasing attention. Tauopathies are a series of progressive neurodegenerative diseases caused by pathological changes in tau, such as abnormal phosphorylation. The pathological features of tauopathies are the deposition of abnormally phosphorylated tau proteins and the aggregation of tau proteins in neurons. This article first describes the normal physiological function and dysfunction of tau proteins and then discusses the enzymes and proteins involved in tau phosphorylation and dephosphorylation, the role of tau in cell dysfunction, and the relationships between tau and several neurodegenerative diseases. The study of tau neurotoxicity provides new directions for the treatment of tauopathies.
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Affiliation(s)
- Shu-Yu Liang
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, No.5 Donghai Middle Road, Qingdao, China
| | - Zuo-Teng Wang
- Department of Neurology, Qingdao Municipal Hospital, College of Medicine and Pharmaceutics, Ocean University of China, Qingdao, China
| | - Lan Tan
- Department of Neurology, Qingdao Municipal Hospital, Qingdao University, No.5 Donghai Middle Road, Qingdao, China. .,Department of Neurology, Qingdao Municipal Hospital, College of Medicine and Pharmaceutics, Ocean University of China, Qingdao, China.
| | - Jin-Tai Yu
- Department of Neurology and Institute of Neurology, Huashan Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Shanghai Medical College, Fudan University, 12th Wulumuqi Zhong Road, Shanghai, 200040, China.
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3
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Barabás K, Kobolák J, Godó S, Kovács T, Ernszt D, Kecskés M, Varga C, Jánosi TZ, Fujiwara T, Kusumi A, Téglási A, Dinnyés A, Ábrahám IM. Live-Cell Imaging of Single Neurotrophin Receptor Molecules on Human Neurons in Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms222413260. [PMID: 34948057 PMCID: PMC8708879 DOI: 10.3390/ijms222413260] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/03/2021] [Accepted: 12/07/2021] [Indexed: 11/16/2022] Open
Abstract
Neurotrophin receptors such as the tropomyosin receptor kinase A receptor (TrkA) and the low-affinity binding p75 neurotrophin receptor p75NTR play a critical role in neuronal survival and their functions are altered in Alzheimer’s disease (AD). Changes in the dynamics of receptors on the plasma membrane are essential to receptor function. However, whether receptor dynamics are affected in different pathophysiological conditions is unexplored. Using live-cell single-molecule imaging, we examined the surface trafficking of TrkA and p75NTR molecules on live neurons that were derived from human-induced pluripotent stem cells (hiPSCs) of presenilin 1 (PSEN1) mutant familial AD (fAD) patients and non-demented control subjects. Our results show that the surface movement of TrkA and p75NTR and the activation of TrkA- and p75NTR-related phosphoinositide-3-kinase (PI3K)/serine/threonine-protein kinase (AKT) signaling pathways are altered in neurons that are derived from patients suffering from fAD compared to controls. These results provide evidence for altered surface movement of receptors in AD and highlight the importance of investigating receptor dynamics in disease conditions. Uncovering these mechanisms might enable novel therapies for AD.
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Affiliation(s)
- Klaudia Barabás
- NAP Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, 7624 Pécs, Hungary; (K.B.); (S.G.); (T.K.); (D.E.); (T.Z.J.); (I.M.Á.)
| | | | - Soma Godó
- NAP Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, 7624 Pécs, Hungary; (K.B.); (S.G.); (T.K.); (D.E.); (T.Z.J.); (I.M.Á.)
| | - Tamás Kovács
- NAP Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, 7624 Pécs, Hungary; (K.B.); (S.G.); (T.K.); (D.E.); (T.Z.J.); (I.M.Á.)
| | - Dávid Ernszt
- NAP Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, 7624 Pécs, Hungary; (K.B.); (S.G.); (T.K.); (D.E.); (T.Z.J.); (I.M.Á.)
| | - Miklós Kecskés
- NAP-B Cortical Microcircuits Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, 7624 Pécs, Hungary; (M.K.); (C.V.)
| | - Csaba Varga
- NAP-B Cortical Microcircuits Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, 7624 Pécs, Hungary; (M.K.); (C.V.)
| | - Tibor Z. Jánosi
- NAP Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, 7624 Pécs, Hungary; (K.B.); (S.G.); (T.K.); (D.E.); (T.Z.J.); (I.M.Á.)
| | - Takahiro Fujiwara
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan;
| | - Akihiro Kusumi
- Membrane Cooperativity Unit, Okinawa Institute of Science and Technology Graduate University (OIST), Onna 904-0495, Japan;
| | | | - András Dinnyés
- BioTalentum Ltd., 2100 Gödöllő, Hungary; (J.K.); (A.T.)
- Correspondence:
| | - István M. Ábrahám
- NAP Molecular Neuroendocrinology Research Group, Institute of Physiology, Medical School, Centre for Neuroscience, Szentágothai Research Institute, University of Pécs, 7624 Pécs, Hungary; (K.B.); (S.G.); (T.K.); (D.E.); (T.Z.J.); (I.M.Á.)
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4
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Abstract
The sympathetic nervous system prepares the body for 'fight or flight' responses and maintains homeostasis during daily activities such as exercise, eating a meal or regulation of body temperature. Sympathetic regulation of bodily functions requires the establishment and refinement of anatomically and functionally precise connections between postganglionic sympathetic neurons and peripheral organs distributed widely throughout the body. Mechanistic studies of key events in the formation of postganglionic sympathetic neurons during embryonic and early postnatal life, including axon growth, target innervation, neuron survival, and dendrite growth and synapse formation, have advanced the understanding of how neuronal development is shaped by interactions with peripheral tissues and organs. Recent progress has also been made in identifying how the cellular and molecular diversity of sympathetic neurons is established to meet the functional demands of peripheral organs. In this Review, we summarize current knowledge of signalling pathways underlying the development of the sympathetic nervous system. These findings have implications for unravelling the contribution of sympathetic dysfunction stemming, in part, from developmental perturbations to the pathophysiology of peripheral neuropathies and cardiovascular and metabolic disorders.
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5
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Odnoshivkina YG, Petrov AM. The Role of Neuro-Cardiac Junctions
in Sympathetic Regulation of the Heart. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021030078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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6
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Pathak A, Clark S, Bronfman FC, Deppmann CD, Carter BD. Long-distance regressive signaling in neural development and disease. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2021; 10:e382. [PMID: 32391977 PMCID: PMC7655682 DOI: 10.1002/wdev.382] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 03/23/2020] [Accepted: 04/06/2020] [Indexed: 02/06/2023]
Abstract
Nervous system development proceeds via well-orchestrated processes involving a balance between progressive and regressive events including stabilization or elimination of axons, synapses, and even entire neurons. These progressive and regressive events are driven by functionally antagonistic signaling pathways with the dominant pathway eventually determining whether a neural element is retained or removed. Many of these developmental sculpting events are triggered by final target innervation necessitating a long-distance mode of communication. While long-distance progressive signaling has been well characterized, particularly for neurotrophic factors, there remains relatively little known about how regressive events are triggered from a distance. Here we discuss the emergent phenomenon of long-distance regressive signaling pathways. In particular, we will cover (a) progressive and regressive cues known to be employed after target innervation, (b) the mechanisms of long-distance signaling from an endosomal platform, (c) recent evidence that long-distance regressive cues emanate from platforms like death receptors or repulsive axon guidance receptors, and (d) evidence that these pathways are exploited in pathological scenarios. This article is categorized under: Nervous System Development > Vertebrates: General Principles Signaling Pathways > Global Signaling Mechanisms Establishment of Spatial and Temporal Patterns > Cytoplasmic Localization.
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Affiliation(s)
- Amrita Pathak
- Department of Biochemistry and Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Shayla Clark
- Neuroscience Graduate Program, University of Virginia, Charlottesville, Virginia
| | - Francisca C. Bronfman
- Institute of Biomedical Sciences (ICB), Faculty of Medicine, Faculty of Life Science, Universidad Andres Bello, Santiago, Chile
| | - Christopher D. Deppmann
- Departments of Biology, Cell Biology, Biomedical Engineering, and Neuroscience, University of Virginia, Charlottesville, Virginia
| | - Bruce D. Carter
- Department of Biochemistry and Vanderbilt Brain Institute, Vanderbilt University School of Medicine, Nashville, Tennessee
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7
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Nerve Growth Factor: The First Molecule of the Neurotrophin Family. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1331:3-10. [PMID: 34453288 DOI: 10.1007/978-3-030-74046-7_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Neurotrophins (NTs) are molecules regulating differentiation, maintenance, and functional plasticity of vertebrate nervous systems. Nerve growth factor (NGF) was the first to be identified in the neurotrophin family. The long scientific history of NTs provided not only advancement in the neuroscience field but opened new scenarios involving different body districts in physiological and pathological conditions, which include the immune, endocrine, and skeletal system, vascular districts, inflammation, etc. To date, many biological aspects of NTs have been clarified, but the new discoveries are still opening new insights on molecular and cellular mechanisms and systemic effects, also affecting the possible therapeutic application of NTs. This short review summarizes the main aspects of NGF biology and biochemistry, including the role of the NGF precursor molecule, high- and low-affinity receptors and related intracellular pathways, and target cells.
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8
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Collura KM, Niu J, Sanders SS, Montersino A, Holland SM, Thomas GM. The palmitoyl acyltransferases ZDHHC5 and ZDHHC8 are uniquely present in DRG axons and control retrograde signaling via the Gp130/JAK/STAT3 pathway. J Biol Chem 2020; 295:15427-15437. [PMID: 32958558 PMCID: PMC7667964 DOI: 10.1074/jbc.ra120.013815] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 09/11/2020] [Indexed: 12/14/2022] Open
Abstract
Palmitoylation, the modification of proteins with the lipid palmitate, is a key regulator of protein targeting and trafficking. However, knowledge of the roles of specific palmitoyl acyltransferases (PATs), which catalyze palmitoylation, is incomplete. For example, little is known about which PATs are present in neuronal axons, although long-distance trafficking of palmitoyl-proteins is important for axon integrity and for axon-to-soma retrograde signaling, a process critical for axon development and for responses to injury. Identifying axonally targeted PATs might thus provide insights into multiple aspects of axonal biology. We therefore comprehensively determined the subcellular distribution of mammalian PATs in dorsal root ganglion (DRG) neurons and, strikingly, found that only two PATs, ZDHHC5 and ZDHHC8, were enriched in DRG axons. Signals via the Gp130/JAK/STAT3 and DLK/JNK pathways are important for axonal injury responses, and we found that ZDHHC5 and ZDHHC8 were required for Gp130/JAK/STAT3, but not DLK/JNK, axon-to-soma signaling. ZDHHC5 and ZDHHC8 robustly palmitoylated Gp130 in cotransfected nonneuronal cells, supporting the possibility that Gp130 is a direct ZDHHC5/8 substrate. In DRG neurons, Zdhhc5/8 shRNA knockdown reduced Gp130 palmitoylation and even more markedly reduced Gp130 surface expression, potentially explaining the importance of these PATs for Gp130-dependent signaling. Together, these findings provide new insights into the subcellular distribution and roles of specific PATs and reveal a novel mechanism by which palmitoylation controls axonal retrograde signaling.
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Affiliation(s)
- Kaitlin M Collura
- Shriners Hospitals Pediatric Research Center (Center for Neurorehabilitation and Neural Repair), Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Jingwen Niu
- Shriners Hospitals Pediatric Research Center (Center for Neurorehabilitation and Neural Repair), Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Shaun S Sanders
- Shriners Hospitals Pediatric Research Center (Center for Neurorehabilitation and Neural Repair), Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Audrey Montersino
- Shriners Hospitals Pediatric Research Center (Center for Neurorehabilitation and Neural Repair), Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Sabrina M Holland
- Shriners Hospitals Pediatric Research Center (Center for Neurorehabilitation and Neural Repair), Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Gareth M Thomas
- Shriners Hospitals Pediatric Research Center (Center for Neurorehabilitation and Neural Repair), Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA; Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA.
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9
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Geden MJ, Romero SE, Deshmukh M. Apoptosis versus axon pruning: Molecular intersection of two distinct pathways for axon degeneration. Neurosci Res 2018; 139:3-8. [PMID: 30452947 DOI: 10.1016/j.neures.2018.11.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 11/02/2018] [Accepted: 11/07/2018] [Indexed: 12/16/2022]
Abstract
Neurons are capable of degenerating their axons for the physiological clearance and refinement of unnecessary connections via the programmed degenerative pathways of apoptosis and axon pruning. While both pathways mediate axon degeneration they are however distinct. Whereas in apoptosis the entire neuron, both axons and cell body, degenerates, in the context of axon pruning only the targeted axon segments are selectively degenerated. Interestingly, the molecular pathways mediating axon degeneration in these two contexts have significant mechanistic overlap but also retain distinct differences. In this review, we describe the peripheral neuronal cell culture models used to study the molecular pathways of apoptosis and pruning. We outline what is known about the molecular mechanisms of apoptosis and axon pruning and focus on highlighting the similarities and differences of these two pathways.
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Affiliation(s)
- Matthew J Geden
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, 27599, USA; Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Selena E Romero
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, 27599, USA; Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Mohanish Deshmukh
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, NC, 27599, USA; Neuroscience Center, University of North Carolina, Chapel Hill, NC, 27599, USA.
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10
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Efficient Promotion of Autophagy and Angiogenesis Using Mesenchymal Stem Cell Therapy Enhanced by the Low-Energy Shock Waves in the Treatment of Erectile Dysfunction. Stem Cells Int 2018; 2018:1302672. [PMID: 30228820 PMCID: PMC6136471 DOI: 10.1155/2018/1302672] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 06/03/2018] [Accepted: 06/24/2018] [Indexed: 12/28/2022] Open
Abstract
Background Mesenchymal stem cell therapy (MSCT) and defocused low-energy shock wave therapy (ESWT) has been shown to ameliorate erectile dysfunction (ED). However, the interactions and effects of action between MSCT and ESWT remain poorly understood. In this study, we investigated the mechanisms of combination therapy with MSCT and ESWT in a rat model of diabetic ED. Materials and Methods Eight-week-old male Sprague-Dawley rats were randomly divided into 2 parts. Diabetic rats induced by streptozotocin (65 mg/kg) were randomly divided into 4 groups: (1) DM control group, (2) DM + ESWT group, (3) DM + MSCT group, and (4) DM + ESWT + MSCT group. The sham group was a normal control group (without streptozotocin). MSCT and (or) ESWT were, respectively, administered to each group according to the proposal for 8 weeks. Immediately after recording of intracavernous pressure (ICP), the penis was then harvested for histologic analysis, ELISA, and Western blotting. Results The ratio of ICP/MAP was significantly higher in the DM + ESWT + MSCT group than in ESWT or MSCT treated group (P < 0.05). Also, the treatment stimulated angiogenesis and vasodilatation in the corpus cavernosum (P < 0.05). ESWT increased the quantity of MSCs in the corpus cavernosum and also induced MSCs to express more VEGF in vitro and vivo (P < 0.05) which activated the PI3K/AKT/mTOR and NO/cGMP signaling pathways in the corpus cavernosum. The combination approach stimulated autophagy and decreased apoptosis in the corpus cavernosum. NGF and BDNF expressions were higher in the DM + ESWT + MSCT group than in the DM control group (P < 0.01). Furthermore, the treatment promoted the MSC recruitment by inducing penile tissues to express more PECAM and SDF-1. Conclusions Combination of LI-ESWT and MSCT can get a better result than a single treatment by expressing more VEGF which can take part in autophagy by triggering the PI3K/AKT/mTOR signaling pathway. This cooperative therapy would provide a new research direction in ED treatment for the future.
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11
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Pathak A, Stanley EM, Hickman FE, Wallace N, Brewer B, Li D, Gluska S, Perlson E, Fuhrmann S, Akassoglou K, Bronfman F, Casaccia P, Burnette DT, Carter BD. Retrograde Degenerative Signaling Mediated by the p75 Neurotrophin Receptor Requires p150 Glued Deacetylation by Axonal HDAC1. Dev Cell 2018; 46:376-387.e7. [PMID: 30086304 PMCID: PMC6093198 DOI: 10.1016/j.devcel.2018.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 05/19/2018] [Accepted: 07/01/2018] [Indexed: 12/23/2022]
Abstract
During development, neurons undergo apoptosis if they do not receive adequate trophic support from tissues they innervate or when detrimental factors activate the p75 neurotrophin receptor (p75NTR) at their axon ends. Trophic factor deprivation (TFD) or activation of p75NTR in distal axons results in a retrograde degenerative signal. However, the nature of this signal and the regulation of its transport are poorly understood. Here, we identify p75NTR intracellular domain (ICD) and histone deacetylase 1 (HDAC1) as part of a retrograde pro-apoptotic signal generated in response to TFD or ligand binding to p75NTR in sympathetic neurons. We report an unconventional function of HDAC1 in retrograde transport of a degenerative signal and its constitutive presence in sympathetic axons. HDAC1 deacetylates dynactin subunit p150Glued, which enhances its interaction with dynein. These findings define p75NTR ICD as a retrograde degenerative signal and reveal p150Glued deacetylation as a unique mechanism regulating axonal transport.
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Affiliation(s)
- Amrita Pathak
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Emily M Stanley
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - F Edward Hickman
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA
| | - Natalie Wallace
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Bryson Brewer
- Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Deyu Li
- Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Shani Gluska
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Eran Perlson
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Sabine Fuhrmann
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA; Department of Ophthalmology and Visual Sciences, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Katerina Akassoglou
- Gladstone Institute of Neurological Disease and Department of Neurology, University of California, San Francisco, CA, USA
| | - Francisca Bronfman
- Center for Ageing and Regeneration (CARE UC), Faculty of Biological Sciences, Department of Physiology, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Patrizia Casaccia
- Hunter College Department of Biology, Advanced Science Research Center at The Graduate Center of the City University of New York, New York, NY, USA
| | - Dylan T Burnette
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Bruce D Carter
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.
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12
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Asghari Adib E, Smithson LJ, Collins CA. An axonal stress response pathway: degenerative and regenerative signaling by DLK. Curr Opin Neurobiol 2018; 53:110-119. [PMID: 30053694 DOI: 10.1016/j.conb.2018.07.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/02/2018] [Indexed: 02/08/2023]
Abstract
Signaling through the dual leucine zipper-bearing kinase (DLK) is required for injured neurons to initiate new axonal growth; however, activation of this kinase also leads to neuronal degeneration and death in multiple models of injury and neurodegenerative diseases. This has spurred current consideration of DLK as a candidate therapeutic target, and raises a vital question: in what context is DLK a friend or foe to neurons? Here, we review our current understanding of DLK's function and mechanisms in regulating both regenerative and degenerative responses to axonal damage and stress in the nervous system.
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Affiliation(s)
- Elham Asghari Adib
- Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Laura J Smithson
- Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Catherine A Collins
- Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA.
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13
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Duan L, Hope JM, Guo S, Ong Q, François A, Kaplan L, Scherrer G, Cui B. Optical Activation of TrkA Signaling. ACS Synth Biol 2018; 7:1685-1693. [PMID: 29975841 DOI: 10.1021/acssynbio.8b00126] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Nerve growth factor/tropomyosin receptor kinase A (NGF/TrkA) signaling plays a key role in neuronal development, function, survival, and growth. The pathway is implicated in neurodegenerative disorders including Alzheimer's disease, chronic pain, inflammation, and cancer. NGF binds the extracellular domain of TrkA, leading to the activation of the receptor's intracellular kinase domain. As TrkA signaling is highly dynamic, mechanistic studies would benefit from a tool with high spatial and temporal resolution. Here we present the design and evaluation of four strategies for light-inducible activation of TrkA in the absence of NGF. Our strategies involve the light-sensitive protein Arabidopsis cryptochrome 2 and its binding partner CIB1. We demonstrate successful recapitulation of native NGF/TrkA functions by optical induction of plasma membrane recruitment and homo-interaction of the intracellular domain of TrkA. This approach activates PI3K/AKT and Raf/ERK signaling pathways, promotes neurite growth in PC12 cells, and supports survival of dorsal root ganglion neurons in the absence of NGF. This ability to activate TrkA using light bestows high spatial and temporal resolution for investigating NGF/TrkA signaling.
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Affiliation(s)
- Liting Duan
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Jen M. Hope
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Shunling Guo
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Qunxiang Ong
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Amaury François
- Department of Anesthesiology, Perioperative and Pain Medicine, Department of Molecular and Cellular Physiology, Department of Neurosurgery, Stanford Neurosciences Institute, Stanford University, Palo Alto, California 94304, United States
| | - Luke Kaplan
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Grégory Scherrer
- Department of Anesthesiology, Perioperative and Pain Medicine, Department of Molecular and Cellular Physiology, Department of Neurosurgery, Stanford Neurosciences Institute, Stanford University, Palo Alto, California 94304, United States
- Robertson Investigator, New York Stem Cell Foundation, New York, New York 10019, United States
| | - Bianxiao Cui
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
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14
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Hollville E, Deshmukh M. Physiological functions of non-apoptotic caspase activity in the nervous system. Semin Cell Dev Biol 2017; 82:127-136. [PMID: 29199140 DOI: 10.1016/j.semcdb.2017.11.037] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Revised: 11/22/2017] [Accepted: 11/29/2017] [Indexed: 12/15/2022]
Abstract
Caspases are cysteine proteases that play important and well-defined roles in apoptosis and inflammation. Increasing evidence point to alternative functions of caspases where restricted and localized caspase activation within neurons allows for a variety of non-apoptotic and non-inflammatory processes required for brain development and function. In this review, we highlight sublethal caspase functions in axon and dendrite pruning, neurite outgrowth and dendrite branches formation, as well as in long-term depression and synaptic plasticity. Importantly, as non-apoptotic activity of caspases is often confined in space and time in neurons, we also discuss the mechanisms that restrict caspase activity in order to maintain the neuronal networks in a healthy and functional state.
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Affiliation(s)
| | - Mohanish Deshmukh
- Neuroscience Center, UNC Chapel Hill, Chapel Hill, NC, USA; Department of Cell Biology and Physiology, UNC Chapel Hill, Chapel Hill, NC, USA.
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15
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PROneurotrophins and CONSequences. Mol Neurobiol 2017; 55:2934-2951. [DOI: 10.1007/s12035-017-0505-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 03/21/2017] [Indexed: 01/12/2023]
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16
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Retrograde apoptotic signaling by the p75 neurotrophin receptor. Neuronal Signal 2017; 1:NS20160007. [PMID: 32714573 PMCID: PMC7373242 DOI: 10.1042/ns20160007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/23/2017] [Accepted: 01/25/2017] [Indexed: 02/06/2023] Open
Abstract
Neurotrophins are target-derived factors necessary for mammalian nervous system development and maintenance. They are typically produced by neuronal target tissues and interact with their receptors at axonal endings. Therefore, locally generated neurotrophin signals must be conveyed from the axon back to the cell soma. Retrograde survival signaling by neurotrophin binding to Trk receptors has been extensively studied. However, neurotrophins also bind to the p75 receptor, which can induce apoptosis in a variety of contexts. Selective activation of p75 at distal axon ends has been shown to generate a retrograde apoptotic signal, although the mechanisms involved are poorly understood. The present review summarizes the available evidence for retrograde proapoptotic signaling in general and the role of the p75 receptor in particular, with discussion of unanswered questions in the field. In-depth knowledge of the mechanisms of retrograde apoptotic signaling is essential for understanding the etiology of neurodegeneration in many diseases and injuries.
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17
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Villarin JM, McCurdy EP, Martínez JC, Hengst U. Local synthesis of dynein cofactors matches retrograde transport to acutely changing demands. Nat Commun 2016; 7:13865. [PMID: 28000671 PMCID: PMC5187584 DOI: 10.1038/ncomms13865] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 11/07/2016] [Indexed: 01/16/2023] Open
Abstract
Cytoplasmic dynein mediates retrograde transport in axons, but it is unknown how its transport characteristics are regulated to meet acutely changing demands. We find that stimulus-induced retrograde transport of different cargos requires the local synthesis of different dynein cofactors. Nerve growth factor (NGF)-induced transport of large vesicles requires local synthesis of Lis1, while smaller signalling endosomes require both Lis1 and p150Glued. Lis1 synthesis is also triggered by NGF withdrawal and required for the transport of a death signal. Association of Lis1 transcripts with the microtubule plus-end tracking protein APC is required for their translation in response to NGF stimulation but not for their axonal recruitment and translation upon NGF withdrawal. These studies reveal a critical role for local synthesis of dynein cofactors for the transport of specific cargos and identify association with RNA-binding proteins as a mechanism to establish functionally distinct pools of a single transcript species in axons.
The molecular mechanisms underlying retrograde transport in axons are only partially understood. Villarin et al. show that in cultured DRG neurons, extracellular trophic cues such as NGF dynamically regulate local protein synthesis of dynein cofactors, thus controlling retrograde trafficking in neurons.
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Affiliation(s)
- Joseph M Villarin
- Medical Scientist Training Program, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | - Ethan P McCurdy
- Integrated Program in Cellular, Molecular and Biomedical Studies, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | - José C Martínez
- Medical Scientist Training Program, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
| | - Ulrich Hengst
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.,Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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18
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Axon degeneration: context defines distinct pathways. Curr Opin Neurobiol 2016; 39:108-15. [PMID: 27197022 DOI: 10.1016/j.conb.2016.05.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/02/2016] [Accepted: 05/03/2016] [Indexed: 12/29/2022]
Abstract
Axon degeneration is an essential part of development, plasticity, and injury response and has been primarily studied in mammalian models in three contexts: 1) Axotomy-induced Wallerian degeneration, 2) Apoptosis-induced axon degeneration (axon apoptosis), and 3) Axon pruning. These three contexts dictate engagement of distinct pathways for axon degeneration. Recent advances have identified the importance of SARM1, NMNATs, NAD+ depletion, and MAPK signaling in axotomy-induced Wallerian degeneration. Interestingly, apoptosis-induced axon degeneration and axon pruning have many shared mechanisms both in signaling (e.g. DLK, JNKs, GSK3α/β) and execution (e.g. Puma, Bax, caspase-9, caspase-3). However, the specific mechanisms by which caspases are activated during apoptosis versus pruning appear distinct, with apoptosis requiring Apaf-1 but not caspase-6 while pruning requires caspase-6 but not Apaf-1.
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19
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Putting together the clues of the everlasting neuro-cardiac liaison. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1904-15. [PMID: 26778332 DOI: 10.1016/j.bbamcr.2016.01.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 12/22/2015] [Accepted: 01/04/2016] [Indexed: 12/17/2022]
Abstract
Starting from the late embryonic development, the sympathetic nervous system extensively innervates the heart and modulates its activity during the entire lifespan. The distribution of myocardial sympathetic processes is finely regulated by the secretion of limiting amounts of pro-survival neurotrophic factors by cardiac cells. Norepinephrine release by the neurons rapidly modulates myocardial electrophysiology, and increases the rate and force of cardiomyocyte contractions. Sympathetic processes establish direct interaction with cardiomyocytes, characterized by the presence of neurotransmitter vesicles and reduced cell-cell distance. Whether such contacts have a functional role in both neurotrophin- and catecholamine-dependent communication between the two cell types, is poorly understood. In this review we will address the effects of the sympathetic neuron activity on the myocardium and the hypothesis that the direct neuro-cardiac contact might have a key role both in norepinephrine and neurotrophin mediated signaling. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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20
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Chowdary PD, Che DL, Kaplan L, Chen O, Pu K, Bawendi M, Cui B. Nanoparticle-assisted optical tethering of endosomes reveals the cooperative function of dyneins in retrograde axonal transport. Sci Rep 2015; 5:18059. [PMID: 26656461 PMCID: PMC4674899 DOI: 10.1038/srep18059] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 10/27/2015] [Indexed: 01/01/2023] Open
Abstract
Dynein-dependent transport of organelles from the axon terminals to the cell bodies is essential to the survival and function of neurons. However, quantitative knowledge of dyneins on axonal organelles and their collective function during this long-distance transport is lacking because current technologies to do such measurements are not applicable to neurons. Here, we report a new method termed nanoparticle-assisted optical tethering of endosomes (NOTE) that made it possible to study the cooperative mechanics of dyneins on retrograde axonal endosomes in live neurons. In this method, the opposing force from an elastic tether causes the endosomes to gradually stall under load and detach with a recoil velocity proportional to the dynein forces. These recoil velocities reveal that the axonal endosomes, despite their small size, can recruit up to 7 dyneins that function as independent mechanical units stochastically sharing load, which is vital for robust retrograde axonal transport. This study shows that NOTE, which relies on controlled generation of reactive oxygen species, is a viable method to manipulate small cellular cargos that are beyond the reach of current technology.
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Affiliation(s)
- Praveen D. Chowdary
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, CA 94305, USA
| | - Daphne L. Che
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, CA 94305, USA
| | - Luke Kaplan
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, CA 94305, USA
| | - Ou Chen
- Department of Chemistry, Massachussets Institute of Technology, 77 Massachussets Ave, Cambridge, MA 02139, USA
| | - Kanyi Pu
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, N1.3, B2-05, Singapore 637459
| | - Moungi Bawendi
- Department of Chemistry, Massachussets Institute of Technology, 77 Massachussets Ave, Cambridge, MA 02139, USA
| | - Bianxiao Cui
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, CA 94305, USA
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21
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Shoemark DK, Williams C, Fahey MS, Watson JJ, Tyler SJ, Scoltock SJ, Ellis RZ, Wickenden E, Burton AJ, Hemmings JL, Bailey CD, Dawbarn D, Jane DE, Willis CL, Sessions RB, Allen SJ, Crump MP. Design and nuclear magnetic resonance (NMR) structure determination of the second extracellular immunoglobulin tyrosine kinase A (TrkAIg2) domain construct for binding site elucidation in drug discovery. J Med Chem 2014; 58:767-77. [PMID: 25454499 PMCID: PMC4504729 DOI: 10.1021/jm501307e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
![]()
The tyrosine kinase A (TrkA) receptor
is a validated therapeutic
intervention point for a wide range of conditions. TrkA activation
by nerve growth factor (NGF) binding the second extracellular immunoglobulin
(TrkAIg2) domain triggers intracellular signaling cascades. In the
periphery, this promotes the pain phenotype and, in the brain, cell
survival or differentiation. Reproducible structural information and
detailed validation of protein–ligand interactions aid drug
discovery. However, the isolated TrkAIg2 domain crystallizes as a β-strand-swapped
dimer in the absence of NGF, occluding the binding surface. Here we
report the design and structural validation by nuclear magnetic resonance
spectroscopy of the first stable, biologically active construct of
the TrkAIg2 domain for binding site confirmation. Our structure closely
mimics the wild-type fold of TrkAIg2 in complex with NGF (1WWW.pdb), and the 1H–15N correlation spectra confirm that both
NGF and a competing small molecule interact at the known binding interface
in solution.
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Affiliation(s)
- Debbie K Shoemark
- School of Clinical Sciences, Level 2, Learning and Research, Southmead Hospital , Bristol BS10 5NB, United Kingdom
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22
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Lu XM, Shu YH, Qiu CH, Chen KT, Wang YT. Protective effects and anti-apoptotic role of nerve growth factor on spinal cord neurons in sciatic nerve-injured rats. Neurol Res 2014; 36:814-23. [PMID: 24620979 DOI: 10.1179/1743132814y.0000000333] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVES The purpose of this study is to demonstrate a dependence of spinal cord motoneurons on the communication with their targets, sciatic nerves, and investigate whether the effects of nerve growth factor (NGF) on the spinal cord neuron apoptosis and surviving through the regulation of nuclear factor-kappa B (NF-kappaB) in Schwann cells (SCs) in sciatic nerve injured rats. METHODS Ninety healthy adult Sprague-Dawley rats were divided randomly into normal control group, crushing group, and NGF-intervened group. When sciatic nerve crushed 1, 3, 7, 14, and 21 days, the expression of NF-kappaB in SCs and the apoptosis regulator Bcl-2 and Caspase-3 in spinal cord were examined by immunohistochemistry staining, Western blot analysis, and immunofluorescence double-labeling method, the motor neuron apoptosis were investigated by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL), and the surviving neurons were tested by toluidine blue (Nissl) staining, respectively. All the data were further analyzed with SPSS10·0 application software. RESULTS The level of the expression of NF-kappaB in crushing group enhanced at 1 day after crushing, reached peak at 3 days, and reduced at least until 21 days, which was markedly higher than that in the normal control group. The expression of NF-kappaB in NGF-intervened group showed the same changes, reached peak at 7 days, and reduced until 21 days. However, when compared with crushing group, the expression of NF-kappaB in NGF-intervened group was down-regulated significantly until 3 days after injury, and up-regulated obviously with time going on. The same trend was observed in the time course on motor neuron apoptosis in crushing group and NGF-intervened group after sciatic nerves injury, while the reversing change was found in the surviving neurons. Moreover, the kinetics of Bcl-2 expression in spinal cord was consistent with that of NF-kappaB, while reversing with that of Caspase-3. CONCLUSION The findings revealed that NGF may play a pivotal role of anti-apoptosis in spinal cord neurons through retrograde transport of NF-kappaB in SCs following sciatic nerve injury in rats.
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Abstract
The tropomyosin-related tyrosine kinase (Trk) receptors were initially described as a family of growth factor receptors required for neuronal survival. They have since been shown to influence many aspects of neuronal development and function, including differentiation, outgrowth, and synaptic plasticity. This chapter will give an overview on the biology of Trk receptors within the nervous system. The structure and downstream signaling pathways of the full-length receptors will be described, as well as the biological functions of their truncated isoforms. Finally, the role of Trk receptors in the nervous system in health and disease will be discussed.
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24
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Spatiotemporal intracellular dynamics of neurotrophin and its receptors. Implications for neurotrophin signaling and neuronal function. Handb Exp Pharmacol 2014; 220:33-65. [PMID: 24668469 DOI: 10.1007/978-3-642-45106-5_3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Neurons possess a polarized morphology specialized to contribute to neuronal networks, and this morphology imposes an important challenge for neuronal signaling and communication. The physiology of the network is regulated by neurotrophic factors that are secreted in an activity-dependent manner modulating neuronal connectivity. Neurotrophins are a well-known family of neurotrophic factors that, together with their cognate receptors, the Trks and the p75 neurotrophin receptor, regulate neuronal plasticity and survival and determine the neuronal phenotype in healthy and regenerating neurons. Is it now becoming clear that neurotrophin signaling and vesicular transport are coordinated to modify neuronal function because disturbances of vesicular transport mechanisms lead to disturbed neurotrophin signaling and to diseases of the nervous system. This chapter summarizes our current understanding of how the regulated secretion of neurotrophin, the distribution of neurotrophin receptors in different locations of neurons, and the intracellular transport of neurotrophin-induced signaling in distal processes are achieved to allow coordinated neurotrophin signaling in the cell body and axons.
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25
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Mok SA, Lund K, Lapointe P, Campenot RB. A HaloTag® method for assessing the retrograde axonal transport of the p75 neurotrophin receptor and other proteins in compartmented cultures of rat sympathetic neurons. J Neurosci Methods 2013; 214:91-104. [PMID: 23348044 DOI: 10.1016/j.jneumeth.2013.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 10/19/2012] [Accepted: 01/08/2013] [Indexed: 11/30/2022]
Abstract
We have adapted HaloTag® (HT) technology for use in compartmented cultures of rat sympathetic neurons in order to provide a technique that can be broadly applied to studies of the retrograde transport of molecules that play roles in neurotrophin signaling. Transfected neurons expressing HT protein alone, HT protein fused to the p75 neurotrophin receptor (p75NTR) or HT protein fused to tubulin α-1B were maintained in compartmented cultures in which cell bodies and proximal axons of rat sympathetic neurons reside in proximal compartments and their distal axons extend into distal compartments. HT ligand containing a fluorescent tetramethylrhodamine (TMR) label was applied either in the distal compartments or the proximal compartments, and the transport of labeled proteins was assayed by gel fluorescence imaging and TMR immunoblot. HT protein expressed alone displayed little or no retrograde transport. HT protein fused to either the intracellular C-terminus or the extracellular N-terminus of p75NTR was retrogradely transported. The retrograde transport of p75NTR was augmented when the distal axons were provided with nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) or antibodies to BDNF. The anterograde transport of HT protein fused to the N-terminus of tubulin α-1B was also demonstrated. We conclude that retrograde transport of HT fusion proteins provides a powerful and novel approach in studies of axonal transport.
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Affiliation(s)
- Sue-Ann Mok
- Department of Cell Biology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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26
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Chen M, Maloney JA, Kallop DY, Atwal JK, Tam SJ, Baer K, Kissel H, Kaminker JS, Lewcock JW, Weimer RM, Watts RJ. Spatially coordinated kinase signaling regulates local axon degeneration. J Neurosci 2012; 32:13439-53. [PMID: 23015435 PMCID: PMC6621382 DOI: 10.1523/jneurosci.2039-12.2012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 07/06/2012] [Accepted: 07/28/2012] [Indexed: 01/02/2023] Open
Abstract
In addition to being a hallmark of neurodegenerative disease, axon degeneration is used during development of the nervous system to prune unwanted connections. In development, axon degeneration is tightly regulated both temporally and spatially. Here, we provide evidence that degeneration cues are transduced through various kinase pathways functioning in spatially distinct compartments to regulate axon degeneration. Intriguingly, glycogen synthase kinase-3 (GSK3) acts centrally, likely modulating gene expression in the cell body to regulate distally restricted axon degeneration. Through a combination of genetic and pharmacological manipulations, including the generation of an analog-sensitive kinase allele mutant mouse for GSK3β, we show that the β isoform of GSK3, not the α isoform, is essential for developmental axon pruning in vitro and in vivo. Additionally, we identify the dleu2/mir15a/16-1 cluster, previously characterized as a regulator of B-cell proliferation, and the transcription factor tbx6, as likely downstream effectors of GSK3β in axon degeneration.
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MESH Headings
- Animals
- Animals, Newborn
- Axons/metabolism
- Cells, Cultured
- Electroporation
- Embryo, Mammalian
- Enzyme Inhibitors/pharmacology
- Female
- Ganglia, Spinal/cytology
- Gene Expression Profiling/methods
- Gene Expression Regulation, Developmental/drug effects
- Gene Expression Regulation, Developmental/genetics
- Gene Expression Regulation, Developmental/physiology
- Genotype
- Glycogen Synthase Kinase 3/genetics
- Glycogen Synthase Kinase 3/metabolism
- Glycogen Synthase Kinase 3 beta
- Green Fluorescent Proteins/genetics
- Hippocampus/cytology
- Humans
- Immunoprecipitation
- Luminescent Proteins/genetics
- Luminescent Proteins/metabolism
- MAP Kinase Signaling System/drug effects
- MAP Kinase Signaling System/genetics
- MAP Kinase Signaling System/physiology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Mutation/genetics
- Nerve Degeneration/drug therapy
- Nerve Degeneration/enzymology
- Nerve Degeneration/pathology
- Nerve Degeneration/prevention & control
- Nerve Growth Factor/deficiency
- Nerve Tissue Proteins/metabolism
- Neurons/pathology
- Oligonucleotide Array Sequence Analysis
- Organ Culture Techniques
- Phosphorylation/physiology
- Phosphotransferases/metabolism
- RNA, Small Interfering/administration & dosage
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Retinal Ganglion Cells/metabolism
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Transfection
- Red Fluorescent Protein
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Affiliation(s)
| | | | | | | | | | | | | | - Joshua S. Kaminker
- Bioinformatics, Genentech, Inc., South San Francisco, California 94080, and
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27
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Induction of apoptosis accelerates reactivation of latent HSV-1 in ganglionic organ cultures and replication in cell cultures. Proc Natl Acad Sci U S A 2012; 109:14616-21. [PMID: 22908263 DOI: 10.1073/pnas.1212661109] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Herpes simplex viruses replicate at the portal of entry into the body and are transported retrograde to sensory neurons in which they can establish a silent, latent infection characterized by the expression of a noncoding latency-associated transcript and a set of microRNAs. At the portal of entry into the body and in cell culture a viral protein, VP16, recruits cellular proteins that initiate a sequential derepression of several kinetic classes of viral genes. Earlier studies have shown that upon reactivation of latent virus in ganglionic organ cultures all genes are derepressed at once, thus obviating the need for VP16 to initiate sequential derepression of viral genes. One hypothesis that could explain the data is that the massive reactivation of all classes of viral genes is the consequence of activation of an apoptotic pathway. Here we show that two proapoptotic drugs, dexamethasone and 2[[3-(2,3-dichlorophenoxy)propyl]amino]-ethanol, each accelerates viral gene expression in ganglionic organ cultures. We also show that in cultured cells apoptosis induced by dexamethasone accelerates viral gene expression and accumulation of infectious virus. The results are surprising in light of the relatively large number of viral proteins that independently block apoptosis induced by viral gene products or exogenous agents. The results suggest that the virus may rely on apoptosis to exit from latency but that apoptosis may be detrimental for virus replication or spread at the portal of entry into the body.
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28
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Ascano M, Bodmer D, Kuruvilla R. Endocytic trafficking of neurotrophins in neural development. Trends Cell Biol 2012; 22:266-73. [PMID: 22444728 DOI: 10.1016/j.tcb.2012.02.005] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 02/17/2012] [Accepted: 02/17/2012] [Indexed: 01/19/2023]
Abstract
During the formation of neuronal circuits, neurons respond to diffusible cues secreted by target tissues. Often, target-derived signals act on nerve terminals to influence local growth events; in other cases, they are transported long distances back to neuronal cell bodies to effect transcriptional changes necessary for neuronal survival and differentiation. Neurotrophins provide one of the best examples of target-derived cues that elicit an astonishingly diverse array of neuronal responses. Endocytic trafficking of neurotrophins and their receptors is a fundamental feature of neurotrophin signaling, allowing neurotrophins to control neuronal survival by retrograde transport of signaling endosomes containing ligand-receptor complexes. In this review we summarize recent findings that provide new insight into the interplay between neurotrophin signaling and trafficking.
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Affiliation(s)
- Maria Ascano
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
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29
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JNK2 and JNK3 are major regulators of axonal injury-induced retinal ganglion cell death. Neurobiol Dis 2012; 46:393-401. [PMID: 22353563 DOI: 10.1016/j.nbd.2012.02.003] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 01/30/2012] [Accepted: 02/04/2012] [Indexed: 01/21/2023] Open
Abstract
Glaucoma is a neurodegenerative disease characterized by the apoptotic death of retinal ganglion cells (RGCs). The primary insult to RGCs in glaucoma is thought to occur to their axons as they exit the eye in the optic nerve head. However, pathological signaling pathways that exert central roles in triggering RGC death following axonal injury remain unidentified. It is likely that the first changes to occur following axonal injury are signal relay events that transduce the injury signal from the axon to the cell body. Here we focus on the c-Jun N-terminal kinase (JNK1-3) family, a signaling pathway implicated in axonal injury signaling and neurodegenerative apoptosis, and likely to function as a central node in axonal injury-induced RGC death. We show that JNK signaling is activated immediately after axonal injury in RGC axons at the site of injury. Following its early activation, sustained JNK signaling is observed in axonally-injured RGCs in the form of JUN phosphorylation and upregulation. Using mice lacking specific Jnk isoforms, we show that Jnk2 and Jnk3 are the isoforms activated in injured axons. Combined deficiency of Jnk2 and Jnk3 provides robust long-term protection against axonal injury-induced RGC death and prevents downregulation of the RGC marker, BRN3B, and phosphorylation of JUN. Finally, using Jun deficient mice, we show that JUN-dependent pathways are important for axonal injury-induced RGC death. Together these data demonstrate that JNK signaling is the major early pathway triggering RGC death after axonal injury and may directly link axon injury to transcriptional activity that controls RGC death.
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30
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Ghosh AS, Wang B, Pozniak CD, Chen M, Watts RJ, Lewcock JW. DLK induces developmental neuronal degeneration via selective regulation of proapoptotic JNK activity. ACTA ACUST UNITED AC 2012; 194:751-64. [PMID: 21893599 PMCID: PMC3171129 DOI: 10.1083/jcb.201103153] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
DLK is part of a specialized JNK signaling complex in axons that promotes apoptosis via c-Jun but axon degeneration via distinct JNK substrates. The c-Jun N-terminal kinase (JNK) signaling pathway is essential for neuronal degeneration in multiple contexts but also regulates neuronal homeostasis. It remains unclear how neurons are able to dissociate proapoptotic JNK signaling from physiological JNK activity. In this paper, we show that the mixed lineage kinase dual leucine zipper kinase (DLK) selectively regulates the JNK-based stress response pathway to mediate axon degeneration and neuronal apoptosis without influencing other aspects of JNK signaling. This specificity is dependent on interaction of DLK with the scaffolding protein JIP3 to form a specialized JNK signaling complex. Local activation of DLK-based signaling in the axon results in phosphorylation of c-Jun and apoptosis after redistribution of JNK to the cell body. In contrast, regulation of axon degeneration by DLK is c-Jun independent and mediated by distinct JNK substrates. DLK-null mice displayed reduced apoptosis in multiple neuronal populations during development, demonstrating that prodegenerative DLK signaling is required in vivo.
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Affiliation(s)
- Arundhati Sengupta Ghosh
- Neurodegeneration Laboratories, Department of Neuroscience, Genentech, Inc., South San Francisco, CA 94080, USA
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Rotshenker S. Wallerian degeneration: the innate-immune response to traumatic nerve injury. J Neuroinflammation 2011; 8:109. [PMID: 21878125 PMCID: PMC3179447 DOI: 10.1186/1742-2094-8-109] [Citation(s) in RCA: 312] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 08/30/2011] [Indexed: 12/23/2022] Open
Abstract
Traumatic injury to peripheral nerves results in the loss of neural functions. Recovery by regeneration depends on the cellular and molecular events of Wallerian degeneration that injury induces distal to the lesion site, the domain through which severed axons regenerate back to their target tissues. Innate-immunity is central to Wallerian degeneration since innate-immune cells, functions and molecules that are produced by immune and non-immune cells are involved. The innate-immune response helps to turn the peripheral nerve tissue into an environment that supports regeneration by removing inhibitory myelin and by upregulating neurotrophic properties. The characteristics of an efficient innate-immune response are rapid onset and conclusion, and the orchestrated interplay between Schwann cells, fibroblasts, macrophages, endothelial cells, and molecules they produce. Wallerian degeneration serves as a prelude for successful repair when these requirements are met. In contrast, functional recovery is poor when injury fails to produce the efficient innate-immune response of Wallerian degeneration.
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Affiliation(s)
- Shlomo Rotshenker
- Dept. of Medical Neurobiology, IMRIC, Hebrew University, Faculty of Medicine, Jerusalem, Israel.
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Niewiadomska G, Mietelska-Porowska A, Mazurkiewicz M. The cholinergic system, nerve growth factor and the cytoskeleton. Behav Brain Res 2011; 221:515-26. [DOI: 10.1016/j.bbr.2010.02.024] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 02/10/2010] [Indexed: 01/02/2023]
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Gerdts J, Sasaki Y, Vohra B, Marasa J, Milbrandt J. Image-based screening identifies novel roles for IkappaB kinase and glycogen synthase kinase 3 in axonal degeneration. J Biol Chem 2011; 286:28011-8. [PMID: 21685387 DOI: 10.1074/jbc.m111.250472] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Axon degeneration is an active, evolutionarily conserved self-destruction program by which compromised axons fragment in response to varied insults. Unlike programmed cell death, axon degeneration is poorly understood. We have combined robotic liquid handling with automated microscopy and image analysis to create a robust screening platform to measure axon degeneration in mammalian primary neuronal cultures. Using this assay, we performed an unbiased screen of 480 bioactive compounds, identifying 11 that reproducibly delay fragmentation of severed axons in vitro, including two inhibitors of glycogen synthase kinase 3 and two inhibitors of IκB kinase. Knockdown of each of these targets by shRNA lentivirus also delays axon degeneration in vitro, further supporting their role in the axon degeneration program.
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Affiliation(s)
- Josiah Gerdts
- Department of Genetics, Washington University Medical School, St Louis, Missouri 63110, USA
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Vohra BPS, Sasaki Y, Miller BR, Chang J, DiAntonio A, Milbrandt J. Amyloid precursor protein cleavage-dependent and -independent axonal degeneration programs share a common nicotinamide mononucleotide adenylyltransferase 1-sensitive pathway. J Neurosci 2010; 30:13729-38. [PMID: 20943913 PMCID: PMC3104322 DOI: 10.1523/jneurosci.2939-10.2010] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 07/15/2010] [Accepted: 07/26/2010] [Indexed: 11/21/2022] Open
Abstract
Axonal degeneration is a hallmark of many debilitating neurological disorders and is thought to be regulated by mechanisms distinct from those governing cell body death. Recently, caspase 6 activation via amyloid precursor protein (APP) cleavage and activation of DR6 was discovered to induce axon degeneration after NGF withdrawal. We tested whether this pathway is involved in axonal degeneration caused by withdrawal of other trophic support, axotomy or vincristine exposure. Neurturin deprivation, like NGF withdrawal activated this APP/DR6/caspase 6 pathway and resulted in axonal degeneration, however, APP cleavage and caspase 6 activation were not involved in axonal degeneration induced by mechanical or toxic insults. However, loss of surface APP (sAPP) and caspase 6 activation were observed during axonal degeneration induced by dynactin 1(Dctn1) dysfunction, which disrupts axonal transport. Mutations in Dctn1 are associated with motor neuron disease and frontal temporal dementia, thus suggesting that the APP/caspase 6 pathway could be important in specific types of disease-associated axonal degeneration. The NGF deprivation paradigm, with its defined molecular pathway, was used to examine the context of Nmnat-mediated axonal protection. We found that although Nmnat blocks axonal degeneration after trophic factor withdrawal, it did not prevent loss of axon sAPP or caspase 6 activation within the axon, suggesting it acts downstream of caspase 6. These results indicate that diverse insults induce axonal degeneration via multiple pathways and that these degeneration signals converge on a common, Nmnat-sensitive program that is uniquely involved in axonal, but not cell body, degeneration.
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Affiliation(s)
- Bhupinder P. S. Vohra
- Departments of Genetics and
- Biology Department, University of Central Arkansas, Conway, Arkansas 72034
| | | | | | | | - Aaron DiAntonio
- Developmental Biology, and
- HOPE Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110, and
| | - Jeffrey Milbrandt
- Departments of Genetics and
- HOPE Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110, and
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Fitzgerald M, Bartlett CA, Harvey AR, Dunlop SA. Early events of secondary degeneration after partial optic nerve transection: an immunohistochemical study. J Neurotrauma 2010; 27:439-52. [PMID: 19852581 DOI: 10.1089/neu.2009.1112] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Secondary degeneration in the central nervous system involves indirect damage to neurons and glia away from the initial injury. Partial transection of the dorsal optic nerve (ON) results in precise spatial separation of the primary trauma from delayed degenerative events in ventrally placed axons and parent somata. Here we conduct an immunohistochemical survey of secondary cellular changes in and around axons and their parent retinal ganglion cell (RGC) somata during the first 3 days after a restricted, dorsal ON transection. This is before the secondary loss of RGCs and axons projecting through the uninjured, ventral portion of the ON. Within 5 min, manganese superoxide dismutase (MnSOD; a marker of oxidative stress) co-localizes within the astrocytic network across the entire profile of the ON. Secondary astrocyte hypertrophy of immunofluorescent labeling was evident from 3 h, with sustained increases in myelin basic protein immunoreactivity across the nerve by 24 h. Increases in NG-2-positive oligodendrocyte precursor cells, ED-1-positive activated microglia/macrophages, and Iba1-positive reactive resident microglia/macrophage numbers were only seen in ON vulnerable to secondary degeneration by 3 days. Changes within RGC somata exclusively vulnerable to secondary degeneration were detected at 24 h, as evidenced by increases in MnSOD immunoreactivity, followed by increases in c-jun immunoreactivity at 3 days. Treatment with the voltage-gated calcium channel blocker lomerizine did not alter any measured outcome. We conclude that oxidative stress spreading via the astrocytic network and from injured axons to parent RGC somata is an early event during secondary degeneration, and containment is likely to be required in order to prevent further damage to the nerve.
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Affiliation(s)
- Melinda Fitzgerald
- Experimental and Regenerative Neurosciences, School of Animal Biology, Western Australian Institute of Medical Research, 6009, Western Australia, Australia.
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Perlson E, Maday S, Fu MM, Moughamian AJ, Holzbaur ELF. Retrograde axonal transport: pathways to cell death? Trends Neurosci 2010; 33:335-44. [PMID: 20434225 DOI: 10.1016/j.tins.2010.03.006] [Citation(s) in RCA: 249] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 03/22/2010] [Accepted: 03/26/2010] [Indexed: 12/11/2022]
Abstract
Active transport along the axon is crucial to the neuron. Motor-driven transport supplies the distal synapse with newly synthesized proteins and lipids, and clears damaged or misfolded proteins. Microtubule motors also drive long-distance signaling along the axon via signaling endosomes. Although positive signaling initiated by neurotrophic factors has been well-studied, recent research has focused on stress-signaling along the axon. Here, the connections between axonal transport alterations and neurodegeneration are discussed, including evidence for defective transport of vesicles, mitochondria, degradative organelles, and signaling endosomes in models of amyotrophic lateral sclerosis, Huntington's, Parkinson's and Alzheimer's disease. Defects in transport are sufficient to induce neurodegeneration, but recent progress suggests that changes in retrograde signaling pathways correlate with rapidly progressive neuronal cell death.
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Affiliation(s)
- Eran Perlson
- Department of Physiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19067, USA
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Dahlstrom AB. Fast intra-axonal transport: Beginning, development and post-genome advances. Prog Neurobiol 2010; 90:119-45. [DOI: 10.1016/j.pneurobio.2009.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 11/23/2009] [Accepted: 11/23/2009] [Indexed: 01/02/2023]
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38
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Campenot RB, Lund K, Mok SA. Production of compartmented cultures of rat sympathetic neurons. Nat Protoc 2009; 4:1869-87. [DOI: 10.1038/nprot.2009.210] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Yano H, Torkin R, Martin LA, Chao MV, Teng KK. Proneurotrophin-3 is a neuronal apoptotic ligand: evidence for retrograde-directed cell killing. J Neurosci 2009; 29:14790-802. [PMID: 19940174 PMCID: PMC2824605 DOI: 10.1523/jneurosci.2059-09.2009] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 09/01/2009] [Accepted: 10/13/2009] [Indexed: 12/20/2022] Open
Abstract
Although mature neurotrophins are well described trophic factors that elicit retrograde survival signaling, the precursor forms of neurotrophins (i.e., proneurotrophins) can function as high-affinity apoptotic ligands for selected neural populations. An outstanding question is whether target-derived proneurotrophins might affect neuronal survival/death decisions through a retrograde transport mechanism. Since neurotrophin-3 (NT-3) is highly expressed in non-neural tissues that receive peripheral innervation, we investigated the localized actions of its precursor (proNT-3) on sympathetic neurons in the present study. Pharmacological inhibition of intracellular furin proteinase activity in 293T cells resulted in proNT-3 release instead of mature NT-3, whereas membrane depolarization in cerebellar granule neurons stimulated endogenous proNT-3 secretion, suggesting that proNT-3 is an inducible bona fide ligand in the nervous system. Our data also indicate that recombinant proNT-3 induced sympathetic neuron death that is p75(NTR)- and sortilin-dependent, with hallmark features of apoptosis including JNK (c-Jun N-terminal kinase) activation and nuclear fragmentation. Using compartmentalized culture systems that segregate neuronal cell bodies from axons, proNT-3, acting within the distal axon compartment, elicited sympathetic neuron death and overrode the survival-promoting actions of NGF. Together, these results raise the intriguing possibility that dysregulation of proneurotrophin processing/release by innervated targets can be deleterious to the neurons projecting to these sites.
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Affiliation(s)
- Hiroko Yano
- Molecular Neurobiology Program, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York 10016
| | - Risa Torkin
- Department of Medicine, Weill Cornell Medical College, New York, New York 10065, and
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | - Laura Andrés Martin
- Department of Medicine, Weill Cornell Medical College, New York, New York 10065, and
| | - Moses V. Chao
- Molecular Neurobiology Program, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York 10016
| | - Kenneth K. Teng
- Department of Medicine, Weill Cornell Medical College, New York, New York 10065, and
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Fates of neurotrophins after retrograde axonal transport: phosphorylation of p75NTR is a sorting signal for delayed degradation. J Neurosci 2009; 29:10715-29. [PMID: 19710323 DOI: 10.1523/jneurosci.2512-09.2009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Neurotrophins can mediate survival or death of neurons. Opposing functions of neurotrophins are based on binding of these ligands to two distinct types of receptors: trk receptors and p75NTR. Previous work showed that target-derived NGF induces cell death, whereas BDNF and NT-3 enhance survival of neurons in the isthmo-optic nucleus of avian embryos. To determine the fate of retrogradely transported neurotrophins and test whether their sorting differs between neurotrophins mediating survival- or death-signaling pathways, we traced receptor-binding, sorting, and degradation kinetics of target-applied radiolabeled neurotrophins that bind in this system to trk receptors (BDNF, NT-3) or only to p75NTR (NGF). At the ultrastructural level, the p75NTR-bound NGF accumulates with a significant delay in multivesicular bodies and organelles of the degradation pathway on arrival in the cell body when compared with trk-bound BDNF or NT-3. This delayed lysosomal accumulation was restricted to target-derived NGF, but was not seen when NGF was supplied to the soma in vitro. The kinase inhibitors K252a and Gö6976 alter the kinetics of organelle accumulation: phosphorylation of p75NTR is a sorting signal for delayed sequestering of p75NTR-bound NGF in multivesicular bodies and delayed degradation in lysosomes when compared with trk-bound neurotrophins. Mutagenesis and mass spectrometry studies indicate that p75NTR is phosphorylated by conventional protein kinase C on serine 266. We conclude that, in addition to the known phosphorylation of trks, the phosphorylation of p75NTR can also significantly affect neuronal survival in vivo by changing the intracellular sorting and degradation kinetics of its ligands and thus signaling duration.
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NGF uptake and retrograde signaling mechanisms in sympathetic neurons in compartmented cultures. Results Probl Cell Differ 2009; 48:141-58. [PMID: 19343309 DOI: 10.1007/400_2009_7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Many neurons depend for their survival on retrograde signals to their cell bodies generated by nerve growth factor (NGF) or other neurotrophins at their axon terminals. Apoptosis resulting from the loss of retrograde NGF signaling contributes to the elimination of excess and misconnected neurons during development and to the death of neurons during the course of neurodegenerative diseases. Possible mechanisms of retrograde signaling include (1) retrograde transport of signaling endosomes, carrying NGF bound to activated TrkA, (2) retrograde transport of signaling molecules downstream of TrkA, and (3) retrograde propagation of a phosphorylation signal without transport of signaling molecules. Evidence is also described, which indicates that two or more retrograde signaling mechanisms exist to regulate neuronal survival, including recent evidence that withdrawal of NGF from distal axons produces a retrograde apoptotic signal, which is transported to the cell bodies, where it initiates the apoptotic program, leading to the death of the neuron.
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