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Kim J, He MJ, Widmann AK, Lee FS. The role of neurotrophic factors in novel, rapid psychiatric treatments. Neuropsychopharmacology 2024; 49:227-245. [PMID: 37673965 PMCID: PMC10700398 DOI: 10.1038/s41386-023-01717-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 07/11/2023] [Accepted: 07/26/2023] [Indexed: 09/08/2023]
Abstract
Neurotrophic factors are a family of growth factors that modulate cellular growth, survival, and differentiation. For many decades, it has been generally believed that a lack of neurotrophic support led to the decreased neuronal synaptic plasticity, death, and loss of non-neuronal supportive cells seen in neuropsychiatric disorders. Traditional psychiatric medications that lead to immediate increases in neurotransmitter levels at the synapse have been shown also to elevate synaptic neurotrophic levels over weeks, correlating with the time course of the therapeutic effects of these drugs. Recent advances in psychiatric treatments, such as ketamine and psychedelics, have shown a much faster onset of therapeutic effects (within minutes to hours). They have also been shown to lead to a rapid release of neurotrophins into the synapse. This has spurred a significant shift in understanding the role of neurotrophins and how the receptor tyrosine kinases that bind neurotrophins may work in concert with other signaling systems. In this review, this renewed understanding of synaptic receptor signaling interactions and the clinical implications of this mechanistic insight will be discussed within the larger context of the well-established roles of neurotrophic factors in psychiatric disorders and treatments.
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Affiliation(s)
- Jihye Kim
- Department of Psychiatry, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Michelle J He
- Department of Psychiatry, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Alina K Widmann
- Department of Psychiatry, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Francis S Lee
- Department of Psychiatry, Weill Cornell Medicine, New York, NY, 10065, USA.
- Department of Pharmacology, Weill Cornell Medicine, New York, NY, 10065, USA.
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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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Podyma B, Parekh K, Güler AD, Deppmann CD. Metabolic homeostasis via BDNF and its receptors. Trends Endocrinol Metab 2021; 32:488-499. [PMID: 33958275 PMCID: PMC8192464 DOI: 10.1016/j.tem.2021.04.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/10/2021] [Accepted: 04/12/2021] [Indexed: 12/12/2022]
Abstract
Metabolic disorders result from dysregulation of central nervous system and peripheral metabolic energy homeostatic pathways. To maintain normal energy balance, neural circuits must integrate feedforward and feedback signals from the internal metabolic environment to orchestrate proper food intake and energy expenditure. These signals include conserved meal and adipocyte cues such as glucose and leptin, respectively, in addition to more novel players including brain-derived neurotrophic factor (BDNF). In particular, BDNF's two receptors, tropomyosin related kinase B (TrkB) and p75 neurotrophin receptor (p75NTR), are increasingly appreciated to be involved in whole body energy homeostasis. At times, these two receptors even seem to functionally oppose one another's actions, providing the framework for a potential neurotrophin mediated energy regulatory axis, which we explore further here.
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Affiliation(s)
- Brandon Podyma
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA; Medical Scientist Training Program, School of Medicine, University of Virginia, Charlottesville, VA 22908-0738, USA.
| | - Kavya Parekh
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Ali D Güler
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
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Suelves N, Miguez A, López-Benito S, Barriga GGD, Giralt A, Alvarez-Periel E, Arévalo JC, Alberch J, Ginés S, Brito V. Early Downregulation of p75 NTR by Genetic and Pharmacological Approaches Delays the Onset of Motor Deficits and Striatal Dysfunction in Huntington's Disease Mice. Mol Neurobiol 2019; 56:935-953. [PMID: 29804232 DOI: 10.1007/s12035-018-1126-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/11/2018] [Indexed: 11/26/2022]
Abstract
Deficits in striatal brain-derived neurotrophic factor (BDNF) delivery and/or BDNF/tropomyosin receptor kinase B (TrkB) signaling may contribute to neurotrophic support reduction and selective early degeneration of striatal medium spiny neurons in Huntington's disease (HD). Furthermore, we and others have demonstrated that TrkB/p75NTR imbalance in vitro increases the vulnerability of striatal neurons to excitotoxic insults and induces corticostriatal synaptic alterations. We have now expanded these studies by analyzing the consequences of BDNF/TrkB/p75NTR imbalance in the onset of motor behavior and striatal neuropathology in HD mice. Our findings demonstrate for the first time that the onset of motor coordination abnormalities, in a full-length knock-in HD mouse model (KI), correlates with the reduction of BDNF and TrkB levels, along with an increase in p75NTR expression. Genetic normalization of p75NTR expression in KI mutant mice delayed the onset of motor deficits and striatal neuropathology, as shown by restored levels of striatal-enriched proteins and dendritic spine density and reduced huntingtin aggregation. We found that the BDNF/TrkB/p75NTR imbalance led to abnormal BDNF signaling, manifested as a diminished activation of TrkB-phospholipase C-gamma pathway but upregulation of c-Jun kinase pathway. Moreover, we confirmed the contribution of the proper balance of BDNF/TrkB/p75NTR on HD pathology by a pharmacological approach using fingolimod. We observed that chronic infusion of fingolimod normalizes p75NTR levels, which is likely to improve motor coordination and striatal neuropathology in HD transgenic mice. We conclude that downregulation of p75NTR expression can delay disease progression suggesting that therapeutic approaches aimed to restore the balance between BDNF, TrkB, and p75NTR could be promising to prevent motor deficits in HD.
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Affiliation(s)
- Nuria Suelves
- Departament de Biomedicina, Facultat de Medicina, Institut de Neurosciències, Universitat de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Andrés Miguez
- Departament de Biomedicina, Facultat de Medicina, Institut de Neurosciències, Universitat de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Saray López-Benito
- Department of Cell Biology and Pathology, Instituto de Neurociencias de Castilla y León (INCyL), University of Salamanca, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Salamanca, Spain
| | - Gerardo García-Díaz Barriga
- Departament de Biomedicina, Facultat de Medicina, Institut de Neurosciències, Universitat de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Albert Giralt
- Departament de Biomedicina, Facultat de Medicina, Institut de Neurosciències, Universitat de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Elena Alvarez-Periel
- Departament de Biomedicina, Facultat de Medicina, Institut de Neurosciències, Universitat de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Juan Carlos Arévalo
- Department of Cell Biology and Pathology, Instituto de Neurociencias de Castilla y León (INCyL), University of Salamanca, Salamanca, Spain
- Institute of Biomedical Research of Salamanca (IBSAL), Salamanca, Spain
| | - Jordi Alberch
- Departament de Biomedicina, Facultat de Medicina, Institut de Neurosciències, Universitat de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Silvia Ginés
- Departament de Biomedicina, Facultat de Medicina, Institut de Neurosciències, Universitat de Barcelona, Barcelona, Spain
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Verónica Brito
- Departament de Biomedicina, Facultat de Medicina, Institut de Neurosciències, Universitat de Barcelona, Barcelona, Spain.
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
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Seiler S, Di Santo S, Sahli S, Andereggen L, Widmer HR. Nogo-receptor 1 antagonization in combination with neurotrophin-4/5 is not superior to single factor treatment in promoting survival and morphological complexity of cultured dopaminergic neurons. Brain Res 2017; 1668:56-64. [PMID: 28535980 DOI: 10.1016/j.brainres.2017.05.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/12/2017] [Accepted: 05/13/2017] [Indexed: 01/25/2023]
Abstract
Cell transplantation using ventral mesencephalic tissue is an experimental approach to treat Parkinson's disease. This approach is limited by poor survival of the transplants and the high number of dopaminergic neurons needed for grafting. Increasing the yield of dopaminergic neurons in donor tissue is of great importance. We have previously shown that antagonization of the Nogo-receptor 1 by NEP1-40 promoted survival of cultured dopaminergic neurons and exposure to neurotrophin-4/5 increased dopaminergic cell densities in organotypic midbrain cultures. We investigated whether a combination of both treatments offers a novel tool to further improve dopaminergic neuron survival. Rat embryonic ventral mesencephalic neurons grown as organotypic free-floating roller tube or primary dissociated cultures were exposed to neurotrophin-4/5 and NEP1-40. The combined and single factor treatment resulted in significantly higher numbers of tyrosine hydroxylase positive neurons compared to controls. Significantly stronger tyrosine hydroxylase signal intensity was detected by Western blotting in the combination-treated cultures compared to controls but not compared to single factor treatments. Neurotrophin-4/5 and the combined treatment showed significantly higher signals for the neuronal marker microtubule-associated protein 2 in Western blots compared to control while no effects were observed for the astroglial marker glial fibrillary acidic protein between groups, suggesting that neurotrophin-4/5 targets mainly neuronal cells. Finally, NEP1-40 and the combined treatment significantly augmented tyrosine hydroxylase positive neurite length. Summarizing, our findings substantiate that antagonization of the Nogo-receptor 1 promotes dopaminergic neurons but does not further increase the yield of dopaminergic neurons and their morphological complexity when combined with neurotrophin-4/5 hinting to the idea that these treatments might exert their effects by activating common downstream pathways.
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Affiliation(s)
- Stefanie Seiler
- Department of Neurosurgery, Neurocenter and Regenerative Neuroscience Cluster, Inselspital, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland; Department of Clinical Research, University of Bern, Switzerland
| | - Stefano Di Santo
- Department of Neurosurgery, Neurocenter and Regenerative Neuroscience Cluster, Inselspital, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland; Department of Clinical Research, University of Bern, Switzerland
| | - Sebastian Sahli
- Department of Neurosurgery, Neurocenter and Regenerative Neuroscience Cluster, Inselspital, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland
| | - Lukas Andereggen
- Department of Neurosurgery, Neurocenter and Regenerative Neuroscience Cluster, Inselspital, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland; Department of Clinical Research, University of Bern, Switzerland
| | - Hans Rudolf Widmer
- Department of Neurosurgery, Neurocenter and Regenerative Neuroscience Cluster, Inselspital, Bern University Hospital, University of Bern, CH-3010 Bern, Switzerland; Department of Clinical Research, University of Bern, Switzerland.
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Kashiwai K, Kajiya M, Matsuda S, Ouhara K, Takeda K, Takata T, Kitagawa M, Fujita T, Shiba H, Kurihara H. Distinction Between Cell Proliferation and Apoptosis Signals Regulated by Brain-Derived Neurotrophic Factor in Human Periodontal Ligament Cells and Gingival Epithelial Cells. J Cell Biochem 2015; 117:1543-55. [PMID: 26581032 DOI: 10.1002/jcb.25446] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 11/17/2015] [Indexed: 01/16/2023]
Abstract
Previously, we reported that brain-derived neurotrophic factor (BDNF) enhances periodontal tissue regeneration by inducing periodontal ligament cell proliferation in vivo. In addition, the down growth of gingival epithelial cells, which comprises a major obstacle to the regeneration, was not observed. However, the underlying molecular mechanism is still unclear. Therefore, this study aimed to investigate the effect of BDNF on cell proliferation and apoptosis in human periodontal ligament (HPL) cells and human gingival epithelial cells (OBA9 cells) and to explore the molecular mechanism in vitro. HPL cells dominantly expressed a BDNF receptor, TrkB, and BDNF increased cell proliferation and ERK phosphorylation. However, its proliferative effect was diminished by a MEK1/2 inhibitor (U0126) and TrkB siRNA transfection. Otherwise, OBA9 cells showed a higher expression level of p75, which is a pan-neurotrophin receptor, than that of HPL cells. BDNF facilitated not cell proliferation but cell apoptosis and JNK phosphorylation in OBA9 cells. A JNK inhibitor (SP600125) and p75 siRNA transfection attenuated the BDNF-induced cell apoptosis. Moreover, OBA9 cells pretreated with SP600125 or p75 siRNA showed cell proliferation by BDNF stimulation, though it was reduced by U0126 and TrkB siRNA. Interestingly, overexpression of p75 in HPL cells upregulated cell apoptosis and JNK phosphorylation by BDNF treatment. These results indicated that TrkB-ERK signaling regulates BDNF-induced cell proliferation, whereas p75-JNK signaling plays roles in cell apoptotic and cytostatic effect of BDNF. Overall, BDNF activates periodontal ligament cells proliferation and inhibits the gingival epithelial cells growth via the distinct pathway. J. Cell. Biochem. 117: 1543-1555, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Kei Kashiwai
- Department of Periodontal Medicine, Applied Life Sciences, Institute of Biomedical & Health Sciences, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Mikihito Kajiya
- Department of Periodontal Medicine, Applied Life Sciences, Institute of Biomedical & Health Sciences, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Shinji Matsuda
- Department of Periodontal Medicine, Applied Life Sciences, Institute of Biomedical & Health Sciences, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Kazuhisa Ouhara
- Department of Periodontal Medicine, Applied Life Sciences, Institute of Biomedical & Health Sciences, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Katsuhiro Takeda
- Department of Periodontal Medicine, Applied Life Sciences, Institute of Biomedical & Health Sciences, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Takashi Takata
- Department of Oral and Maxillofacial Pathology, Basic Life Sciences, Institute of Biomedical and Health Science, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Masae Kitagawa
- Center of Oral Clinical Examination, Hiroshima University Hospital, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Tsuyoshi Fujita
- Department of Periodontal Medicine, Applied Life Sciences, Institute of Biomedical & Health Sciences, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Hideki Shiba
- Department of Periodontal Medicine, Applied Life Sciences, Institute of Biomedical & Health Sciences, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
| | - Hidemi Kurihara
- Department of Periodontal Medicine, Applied Life Sciences, Institute of Biomedical & Health Sciences, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3, Kasumi, Minami-ku, Hiroshima, Japan
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7
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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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Directed evolution of brain-derived neurotrophic factor for improved folding and expression in Saccharomyces cerevisiae. Appl Environ Microbiol 2014; 80:5732-42. [PMID: 25015885 DOI: 10.1128/aem.01466-14] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) plays an important role in nervous system function and has therapeutic potential. Microbial production of BDNF has resulted in a low-fidelity protein product, often in the form of large, insoluble aggregates incapable of binding to cognate TrkB or p75 receptors. In this study, employing Saccharomyces cerevisiae display and secretion systems, it was found that BDNF was poorly expressed and partially inactive on the yeast surface and that BDNF was secreted at low levels in the form of disulfide-bonded aggregates. Thus, for the purpose of increasing the compatibility of yeast as an expression host for BDNF, directed-evolution approaches were employed to improve BDNF folding and expression levels. Yeast surface display was combined with two rounds of directed evolution employing random mutagenesis and shuffling to identify BDNF mutants that had 5-fold improvements in expression, 4-fold increases in specific TrkB binding activity, and restored p75 binding activity, both as displayed proteins and as secreted proteins. Secreted BDNF mutants were found largely in the form of soluble homodimers that could stimulate TrkB phosphorylation in transfected PC12 cells. Site-directed mutagenesis studies indicated that a particularly important mutational class involved the introduction of cysteines proximal to the native cysteines that participate in the BDNF cysteine knot architecture. Taken together, these findings show that yeast is now a viable alternative for both the production and the engineering of BDNF.
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9
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Maruyama IN. Mechanisms of activation of receptor tyrosine kinases: monomers or dimers. Cells 2014; 3:304-30. [PMID: 24758840 PMCID: PMC4092861 DOI: 10.3390/cells3020304] [Citation(s) in RCA: 127] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 04/10/2014] [Accepted: 04/11/2014] [Indexed: 02/06/2023] Open
Abstract
Receptor tyrosine kinases (RTKs) play essential roles in cellular processes, including metabolism, cell-cycle control, survival, proliferation, motility and differentiation. RTKs are all synthesized as single-pass transmembrane proteins and bind polypeptide ligands, mainly growth factors. It has long been thought that all RTKs, except for the insulin receptor (IR) family, are activated by ligand-induced dimerization of the receptors. An increasing number of diverse studies, however, indicate that RTKs, previously thought to exist as monomers, are present as pre-formed, yet inactive, dimers prior to ligand binding. The non-covalently associated dimeric structures are reminiscent of those of the IR family, which has a disulfide-linked dimeric structure. Furthermore, recent progress in structural studies has provided insight into the underpinnings of conformational changes during the activation of RTKs. In this review, I discuss two mutually exclusive models for the mechanisms of activation of the epidermal growth factor receptor, the neurotrophin receptor and IR families, based on these new insights.
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Affiliation(s)
- Ichiro N Maruyama
- Information Processing Biology Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami, Okinawa 904-0495, Japan.
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10
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BDNF mimetic compound LM22A-4 regulates cementoblast differentiation via the TrkB–ERK/Akt signaling cascade. Int Immunopharmacol 2014; 19:245-52. [DOI: 10.1016/j.intimp.2014.01.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 01/11/2014] [Accepted: 01/30/2014] [Indexed: 11/21/2022]
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Candalija A, Cubí R, Ortega A, Aguilera J, Gil C. Trk receptors need neutral sphingomyelinase activity to promote cell viability. FEBS Lett 2013; 588:167-74. [PMID: 24316227 DOI: 10.1016/j.febslet.2013.11.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 11/19/2013] [Accepted: 11/25/2013] [Indexed: 02/07/2023]
Abstract
Neurotrophins are a group of secreted polypeptides, which comprises Nerve Growth Factor (NGF) and Brain-Derived Neurotrophic Factor (BDNF). Each neurotrophin can bind specifically to a tyrosine kinase Trk receptor (TrkA, TrkB or TrkC), while all of the neurotrophins can bind, with similar affinity, to the p75 neurotrophin receptor (p75(NTR)). Experiments on cell viability promotion by BDNF in granule neurons or by NGF in PC12 cells show that neurotrophin-exerted cell viability is neutral sphingomyelinase (nSMase)-dependent, since GW4869 or siRNA knockdown abrogates the protective effects, as well as neurotrophin-induced Akt phosphorylation. Finally, the assessment of nSMase activity promotion drives to the conclusion that neurotrophins can promote cell viability through Trk receptors in a manner depending on basal nSMase but not through SMase activity enhancement.
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Affiliation(s)
- Ana Candalija
- Department of Biochemistry and Molecular Biology, Institute of Neurosciences, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Catalunya, Spain
| | - Roger Cubí
- Department of Biochemistry and Molecular Biology, Institute of Neurosciences, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Catalunya, Spain
| | - Arturo Ortega
- Departamento de Genética y Biología Molecular, Cinvestav-IPN, México DF, Mexico
| | - José Aguilera
- Department of Biochemistry and Molecular Biology, Institute of Neurosciences, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Catalunya, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain.
| | - Carles Gil
- Department of Biochemistry and Molecular Biology, Institute of Neurosciences, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Catalunya, Spain.
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12
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Antila H, Autio H, Turunen L, Harju K, Tammela P, Wennerberg K, Yli-Kauhaluoma J, Huttunen HJ, Castrén E, Rantamäki T. Utilization of in situ ELISA method for examining Trk receptor phosphorylation in cultured cells. J Neurosci Methods 2013; 222:142-6. [PMID: 24239780 DOI: 10.1016/j.jneumeth.2013.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 10/31/2013] [Accepted: 11/02/2013] [Indexed: 01/18/2023]
Abstract
BACKGROUND Trk receptor tyrosine kinases regulate multiple important neuronal processes during the development and in the adulthood. Tyrosine phosphorylation of Trk serves as the initial step in the Trk signaling pathway and indicates receptor' autocatalytic activity. However, methods allowing simple and large-scale Trk phosphorylation analyses in cultured cells are lacking. NEW METHOD We describe an in situ phospho-Trk ELISA (enzyme-linked immunosorbent assay) method where cell culture, receptor stimulation and Trk phosphorylation analysis are all performed on the same multiwell plate. RESULTS In situ phospho-Trk ELISA readily and specifically detects neurotrophin-induced Trk phosphorylation in cultured cells. A proof-of-concept small molecule screening of a library composed of 2000 approved drugs and other bioactive compounds was carried out using this novel method. COMPARISON WITH EXISTING METHODS In situ phospho-Trk ELISA utilizes the principles and advantages of conventional sandwich ELISA in an in situ context. CONCLUSIONS We describe a novel method that can be efficiently used to examine Trk receptor phosphorylation in cultured cells. Principally similar methods can be developed to examine the levels and signaling of any intracellular protein.
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Affiliation(s)
- Hanna Antila
- Neuroscience Center, P.O. Box 56, Viikinkaari 4, FI-00014 University of Helsinki, Finland
| | - Henri Autio
- Neuroscience Center, P.O. Box 56, Viikinkaari 4, FI-00014 University of Helsinki, Finland
| | - Laura Turunen
- Institute For Molecular Medicine Finland (FIMM), P.O. Box 20, Tukholmankatu 8, FI-00014 University of Helsinki, Finland
| | - Kirsi Harju
- Division of Pharmaceutical Chemistry, Faculty of Pharmacy, P.O. Box 56, Viikinkaari 5 E, FI-00014 University of Helsinki, Finland
| | - Päivi Tammela
- Centre for Drug Research, Faculty of Pharmacy, P.O. Box 56, Viikinkaari 5 E, FI-00014 University of Helsinki, Finland
| | - Krister Wennerberg
- Institute For Molecular Medicine Finland (FIMM), P.O. Box 20, Tukholmankatu 8, FI-00014 University of Helsinki, Finland
| | - Jari Yli-Kauhaluoma
- Division of Pharmaceutical Chemistry, Faculty of Pharmacy, P.O. Box 56, Viikinkaari 5 E, FI-00014 University of Helsinki, Finland
| | - Henri J Huttunen
- Neuroscience Center, P.O. Box 56, Viikinkaari 4, FI-00014 University of Helsinki, Finland; Hermo Pharma Ltd., Viikinkaari 4, FI-00790 Helsinki, Finland
| | - Eero Castrén
- Neuroscience Center, P.O. Box 56, Viikinkaari 4, FI-00014 University of Helsinki, Finland
| | - Tomi Rantamäki
- Neuroscience Center, P.O. Box 56, Viikinkaari 4, FI-00014 University of Helsinki, Finland.
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13
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Small-molecule modulation of neurotrophin receptors: a strategy for the treatment of neurological disease. Nat Rev Drug Discov 2013; 12:507-25. [PMID: 23977697 DOI: 10.1038/nrd4024] [Citation(s) in RCA: 198] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Neurotrophins and their receptors modulate multiple signalling pathways to regulate neuronal survival and to maintain axonal and dendritic networks and synaptic plasticity. Neurotrophins have potential for the treatment of neurological diseases. However, their therapeutic application has been limited owing to their poor plasma stability, restricted nervous system penetration and, importantly, the pleiotropic actions that derive from their concomitant binding to multiple receptors. One strategy to overcome these limitations is to target individual neurotrophin receptors — such as tropomyosin receptor kinase A (TRKA), TRKB, TRKC, the p75 neurotrophin receptor or sortilin — with small-molecule ligands. Such small molecules might also modulate various aspects of these signalling pathways in ways that are distinct from the programmes triggered by native neurotrophins. By departing from conventional neurotrophin signalling, these ligands might provide novel therapeutic options for a broad range of neurological indications.
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14
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Rantamäki T, Vesa L, Antila H, Di Lieto A, Tammela P, Schmitt A, Lesch KP, Rios M, Castrén E. Antidepressant drugs transactivate TrkB neurotrophin receptors in the adult rodent brain independently of BDNF and monoamine transporter blockade. PLoS One 2011; 6:e20567. [PMID: 21666748 PMCID: PMC3110188 DOI: 10.1371/journal.pone.0020567] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 05/04/2011] [Indexed: 01/12/2023] Open
Abstract
Background Antidepressant drugs (ADs) have been shown to activate BDNF (brain-derived neurotrophic factor) receptor TrkB in the rodent brain but the mechanism underlying this phenomenon remains unclear. ADs act as monoamine reuptake inhibitors and after prolonged treatments regulate brain bdnf mRNA levels indicating that monoamine-BDNF signaling regulate AD-induced TrkB activation in vivo. However, recent findings demonstrate that Trk receptors can be transactivated independently of their neurotrophin ligands. Methodology In this study we examined the role of BDNF, TrkB kinase activity and monoamine reuptake in the AD-induced TrkB activation in vivo and in vitro by employing several transgenic mouse models, cultured neurons and TrkB-expressing cell lines. Principal Findings Using a chemical-genetic TrkBF616A mutant and TrkB overexpressing mice, we demonstrate that ADs specifically activate both the maturely and immaturely glycosylated forms of TrkB receptors in the brain in a TrkB kinase dependent manner. However, the tricyclic AD imipramine readily induced the phosphorylation of TrkB receptors in conditional bdnf−/− knock-out mice (132.4±8.5% of control; P = 0.01), indicating that BDNF is not required for the TrkB activation. Moreover, using serotonin transporter (SERT) deficient mice and chemical lesions of monoaminergic neurons we show that neither a functional SERT nor monoamines are required for the TrkB phosphorylation response induced by the serotonin selective reuptake inhibitors fluoxetine or citalopram, or norepinephrine selective reuptake inhibitor reboxetine. However, neither ADs nor monoamine transmitters activated TrkB in cultured neurons or cell lines expressing TrkB receptors, arguing that ADs do not directly bind to TrkB. Conclusions The present findings suggest that ADs transactivate brain TrkB receptors independently of BDNF and monoamine reuptake blockade and emphasize the need of an intact tissue context for the ability of ADs to induce TrkB activity in brain.
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Affiliation(s)
- Tomi Rantamäki
- Sigrid Jusélius Laboratory, Neuroscience Center, University of Helsinki, Helsinki, Finland.
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15
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Küchler J, Hartmann W, Waha A, Koch A, Endl E, Wurst P, Kindler D, Mikeska T, Waha A, Goodyer CG, Büttner R, Schilling K, Pietsch T. p75NTR induces apoptosis in medulloblastoma cells. Int J Cancer 2010; 128:1804-12. [DOI: 10.1002/ijc.25508] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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16
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Acute and gradual increases in BDNF concentration elicit distinct signaling and functions in neurons. Nat Neurosci 2010; 13:302-9. [PMID: 20173744 DOI: 10.1038/nn.2505] [Citation(s) in RCA: 263] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Accepted: 01/22/2010] [Indexed: 12/16/2022]
Abstract
Extracellular factors may act on cells in two distinct modes: an acute increase in concentration as a result of regulated secretion, or a gradual increase in concentration when secreted constitutively or from a distant source. We found that cellular responses to brain-derived neurotrophic factor (BDNF) differed markedly depending on how BDNF was delivered. In cultured rat hippocampal neurons, acute and gradual increases in BDNF elicited transient and sustained activation of TrkB receptor and its downstream signaling, respectively, leading to differential expression of Homer1 and Arc. Transient TrkB activation promoted neurite elongation and spine head enlargement, whereas sustained TrkB activation facilitated neurite branch and spine neck elongation. In hippocampal slices, fast and slow increases in BDNF enhanced basal synaptic transmission and LTP, respectively. Thus, the kinetics of TrkB activation is critical for cell signaling and functions. This temporal dimension in cellular signaling may also have implications for the therapeutic drug design.
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17
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A role of nitric oxide in neurite outgrowth of neuroblastoma cells triggered by mevastatin or serum reduction. Neurosci Lett 2010; 468:28-33. [DOI: 10.1016/j.neulet.2009.10.054] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Revised: 10/11/2009] [Accepted: 10/18/2009] [Indexed: 02/06/2023]
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18
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Kajiya M, Shiba H, Fujita T, Ouhara K, Takeda K, Mizuno N, Kawaguchi H, Kitagawa M, Takata T, Tsuji K, Kurihara H. Brain-derived neurotrophic factor stimulates bone/cementum-related protein gene expression in cementoblasts. J Biol Chem 2008; 283:16259-67. [PMID: 18390540 DOI: 10.1074/jbc.m800668200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF), recognized as essential in the developing nervous system, is involved in differentiation and proliferation in non-neuronal cells, such as endothelial cells, osteoblasts, and periodontal ligament cells. We have focused on the application of BDNF to the regeneration of periodontal tissue and indicated that BDNF promotes the regeneration of experimentally created periodontal defects. Cementoblasts form cementum, mineralized tissue, which is key to establishing a functional periodontium. The application of BDNF to the regeneration of periodontal tissue requires elucidation of the mechanism by which BDNF regulates the functions of cementoblasts. In this study, we examined how BDNF regulates the mRNA expression of bone/cementum-related proteins (alkaline phosphatase (ALP), osteopontin (OPN), and bone morphogenetic protein-2 (BMP-2)) in cultures of immortalized human cementoblast-like (HCEM) cells. BDNF elevated the mRNA levels of ALP, OPN, and BMP-2 in HCEM cells. Small interfering RNA (siRNA) for TRKB, a high affinity receptor of BDNF, siRNA for ELK-1, which is a downstream target of ERK1/2, and PD98059, an ERK inhibitor, obviated the increase in the mRNA levels. BDNF increased the levels of phosphorylated ERK1/2 and Elk-1, and the blocking of BDNF signaling by treatment with siRNA for TRKB and PD98059 suppressed the phosphorylation of ERK1/2 and Elk-1. Furthermore, BDNF increased the levels of phosphorylated c-Raf, which activates the ERK signaling pathway. These findings provide the first evidence that the TrkB-c-Raf-ERK1/2-Elk-1 signaling pathway is required for the BDNF-induced mRNA expression of ALP, OPN, and BMP-2 in HCEM cells.
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Affiliation(s)
- Mikihito Kajiya
- Department of Periodontal Medicine, Hiroshima University Graduate School of Biomedical Sciences, Minami-ku, Hiroshima 34-8553, Japan
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19
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Peters A, Conrad M, Hubold C, Schweiger U, Fischer B, Fehm HL. The principle of homeostasis in the hypothalamus-pituitary-adrenal system: new insight from positive feedback. Am J Physiol Regul Integr Comp Physiol 2007; 293:R83-98. [PMID: 17459911 DOI: 10.1152/ajpregu.00907.2006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Feedback control, both negative and positive, is a fundamental feature of biological systems. Some of these systems strive to achieve a state of equilibrium or “homeostasis”. The major endocrine systems are regulated by negative feedback, a process believed to maintain hormonal levels within a relatively narrow range. Positive feedback is often thought to have a destabilizing effect. Here, we present a “principle of homeostasis,” which makes use of both positive and negative feedback loops. To test the hypothesis that this homeostatic concept is valid for the regulation of cortisol, we assessed experimental data in humans with different conditions (gender, obesity, endocrine disorders, medication) and analyzed these data by a novel computational approach. We showed that all obtained data sets were in agreement with the presented concept of homeostasis in the hypothalamus-pituitary-adrenal axis. According to this concept, a homeostatic system can stabilize itself with the help of a positive feedback loop. The brain mineralocorticoid and glucocorticoid receptors—with their known characteristics—fulfill the key functions in the homeostatic concept: binding cortisol with high and low affinities, acting in opposing manners, and mediating feedback effects on cortisol. This study supports the interaction between positive and negative feedback loops in the hypothalamus-pituitary-adrenal system and in this way sheds new light on the function of dual receptor regulation. Current knowledge suggests that this principle of homeostasis could also apply to other biological systems.
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Affiliation(s)
- A Peters
- Department of Internal Medicine I, Endocrinology, University of Luebeck, 23538 Luebeck, Germany.
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20
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Scott ALM, Ramer LM, Soril LJJ, Kwiecien JM, Ramer MS. Targeting myelin to optimize plasticity of spared spinal axons. Mol Neurobiol 2006; 33:91-111. [PMID: 16603791 DOI: 10.1385/mn:33:2:91] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Revised: 11/30/1999] [Accepted: 07/18/2005] [Indexed: 01/30/2023]
Abstract
Functional re-innervation of target neurons following neurological damage such as spinal cord injury is an essential requirement of potential therapies. There are at least two avenues by which this can be achieved: (a) through the regeneration of injured axons and (b) through promoting plasticity of those spared by the initial insult. There are several reasons why the latter approach may be more feasible, not the least of which are the inhibitory character of the glial scar, the often long distances over which injured axons must regrow, and the fact that spared axons are often already in the vicinity of denervated targets. The challenge is to unveil the well-recognized intrinsic plasticity of spared axons in a way that avoids complications, such as pain or autonomic dysfunction. One approach that we as well as others have taken is to target growth-suppressing signaling pathways initiated in spared axons by myelin-derived proteins. This article reviews models used for the study of spinal axon plasticity and describes the anatomical and behavioral effects of interfering with myelinderived proteins, their receptors, and components of their intracellular signaling cascades.
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Affiliation(s)
- Angela L M Scott
- International Collaboration on Repair Discoveries, The University of British Columbia, Vancouver, Canada
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21
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Lebrun B, Bariohay B, Moyse E, Jean A. Brain-derived neurotrophic factor (BDNF) and food intake regulation: A minireview. Auton Neurosci 2006; 126-127:30-8. [PMID: 16632412 DOI: 10.1016/j.autneu.2006.02.027] [Citation(s) in RCA: 153] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2006] [Accepted: 02/27/2006] [Indexed: 10/24/2022]
Abstract
Neurotrophins, and in particular BDNF, play important roles in proliferation, differentiation and survival of neurons during development, as well as in the synaptic activity and plasticity in many groups of mature neurons. Several lines of evidence suggest that BDNF and its high affinity receptor TrkB contribute to food intake and body weight control. In rodents, pharmacological treatments with BDNF induce reduction in food intake, whereas genetic models with an altered BDNF/TrkB signalling display hyperphagia and obesity. Genetic studies in humans have shown that mutations in the BDNF or TrkB genes may account for certain types of obesity or other forms of eating disorders. Since circulating levels of BDNF correlate with eating disorders in humans and peripheral BDNF treatments reduce hyperphagia and hyperglycaemia in obese diabetic rodents, an endocrine role of BDNF appears plausible and requires further investigation. A central anorectic action of BDNF has also been documented, with a primary focus on the hypothalamus and a more recent highlight on the brainstem integrator of energy homeostasis, the dorsal vagal complex. In this review, we will briefly present neurotrophins and their receptors and focus on experimental evidence which point out BDNF as a signalling component of food intake regulation, with a particular emphasis on the localization of the central anorectic action of BDNF.
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Affiliation(s)
- Bruno Lebrun
- Laboratoire de Physiologie Neurovégétative (PNV), UMR Université Paul Cézanne Aix, Marseille III, CNRS (UMR 6153), INRA (UMR 1147), Faculté des sciences et techniques, BP 351, 13397 Marseille cedex 20, France.
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22
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Du Y, Fischer TZ, Clinton-Luke P, Lercher LD, Dreyfus CF. Distinct effects of p75 in mediating actions of neurotrophins on basal forebrain oligodendrocytes. Mol Cell Neurosci 2005; 31:366-75. [PMID: 16356734 DOI: 10.1016/j.mcn.2005.11.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Revised: 10/26/2005] [Accepted: 11/02/2005] [Indexed: 01/17/2023] Open
Abstract
Previous studies indicate that brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and neurotrophin-3 (NT-3) increase myelin basic protein, (MBP) in differentiating basal forebrain (BF) oligodendrocytes (OLGs) (Du, Y., Fischer, T.Z., Lee, L.N., Lercher, L.D., Dreyfus, C. F., 2003. Regionally specific effects of BDNF on oligodendrocytes. Dev. Neurosci. 25, 116-126). While receptors, trk and p75, are expressed by subsets of oligodendrocytes (Du, Y., Fischer, T.Z., Lee, L.N., Lercher, L.D., Dreyfus, C. F., 2003. Regionally specific effects of BDNF on oligodendrocytes. Dev. Neurosci. 25, 116-126), those responsible for affecting differentiation have not been defined. In contrast, studies of peripheral Schwann cells reported that myelination is enhanced by BDNF working through p75, and diminished by trkC mediated processes (Cosgaya, J.M., Chan, J.R., Shooter, E.M., 2002. The neurotrophin receptor p75NTR as a positive modulator of myelination. Science 298, 1245-1248). To define receptors affecting central oligodendrocyte MBP, p75 knockout animals, p75 blocking antibodies, and an inhibitor of neurotrophin binding to p75, PD90780, were utilized. While p75 was implicated in the actions of NGF and NT-3, it did not affect actions of BDNF. On the other hand, K252a, an inhibitor of trk receptors, abolished the effects of the neurotrophins, including BDNF. All neurotrophins activated their respective trk receptors.
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Affiliation(s)
- Yangzhou Du
- Department of Neuroscience and Cell Biology, UMDNJ/Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
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23
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Hiltunen JO, Laurikainen A, Klinge E, Saarma M. Neurotrophin-3 is a target-derived neurotrophic factor for penile erection-inducing neurons. Neuroscience 2005; 133:51-8. [PMID: 15893630 DOI: 10.1016/j.neuroscience.2005.01.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2004] [Revised: 12/18/2004] [Accepted: 01/05/2005] [Indexed: 01/19/2023]
Abstract
The aim of this study was to determine whether the neurotrophins nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin (NT)-3 could act as endogenous target-derived trophic factors for erection-inducing, i.e. penis-projecting major pelvic ganglion (MPG) neurons, and/or penile sensory neurons in adult rat. This was accomplished by studying the expression of NT mRNAs in the penis and their cognate receptors in the MPG and dorsal root ganglia (DRGs), and the retrograde axonal transport of radioiodinated NTs injected into the corpora cavernosa. Northern hybridization showed that NGF, BDNF, and NT-3 mRNAs are expressed in the shaft of the penis. In situ hybridization combined with usage of the retrograde tracer Fluoro-Gold showed that TrkC and p75 receptors are expressed in penis-projecting neurons of the MPG whereas the mRNAs for TrkA and TrkB receptors were undetectable. However, all the NT receptor mRNAs were expressed in penile sensory neurons of sacral level 1 (S1) DRG. (125)I-NT-3 injected into the shaft of the penis was retrogradely transported into the MPG and S1 DRG, whereas radioiodinated NGF and BDNF were transported specifically into the S1 DRG, thus confirming the existence of functional NT receptors in these penile neurons. In conclusion, these data suggest that NT-3 may act as a target-derived neurotrophic factor for both erection-inducing and penile sensory neurons, whereas NGF and BDNF may be more important for the sensory innervation of the penis.
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MESH Headings
- Animals
- Autoradiography
- Blotting, Northern
- Brain-Derived Neurotrophic Factor/biosynthesis
- Brain-Derived Neurotrophic Factor/pharmacokinetics
- Brain-Derived Neurotrophic Factor/physiology
- DNA, Complementary/biosynthesis
- DNA, Complementary/genetics
- Fluorescent Dyes
- Ganglia, Spinal/physiology
- Image Processing, Computer-Assisted
- In Situ Hybridization
- Iodine Radioisotopes
- Male
- Nerve Growth Factors/biosynthesis
- Nerve Growth Factors/physiology
- Neural Pathways/physiology
- Neurons/physiology
- Neurotrophin 3/biosynthesis
- Neurotrophin 3/physiology
- Penile Erection/physiology
- Penis/innervation
- Penis/physiology
- RNA, Complementary/biosynthesis
- RNA, Complementary/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Radiopharmaceuticals
- Rats
- Rats, Wistar
- Receptor Protein-Tyrosine Kinases/physiology
- Receptor, Nerve Growth Factor/physiology
- Stilbamidines
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Affiliation(s)
- J O Hiltunen
- Institute of Biotechnology, P.O. Box 56, Viikki Biocenter, FIN-00014 University of Helsinki, Helsinki, Finland.
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24
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Fayard B, Loeffler S, Weis J, Vögelin E, Krüttgen A. The secreted brain-derived neurotrophic factor precursor pro-BDNF binds to TrkB and p75NTR but not to TrkA or TrkC. J Neurosci Res 2005; 80:18-28. [PMID: 15704182 DOI: 10.1002/jnr.20432] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The neurotrophin brain-derived neurotrophic factor (BDNF) binds to two cell surface receptors: TrkB receptors that promote neuronal survival and differentiation and p75NTR that induces apoptosis or survival. BDNF, as well as the other members of the neurotrophin family, is synthesized as a larger precursor, pro-BDNF, which undergoes posttranslational modifications and proteolytic processing by furin or related proteases. Both mature neurotrophins and uncleaved proneurotrophins are secreted from cells. The bioactivities of proneurotrophins could differ from those of mature, cleaved neurotrophins; therefore, we wanted to test whether pro-BDNF would differ from mature BDNF in its neurotrophin receptor binding and activation. A furin-resistant pro-BDNF, secreted from COS-7 cells, bound to TrkB-Fc and p75NTR-Fc, but not to TrkA-Fc or TrkC-Fc. Likewise, pro-BDNF elicited prototypical TrkB responses in biological assays, such as TrkB tyrosine phosphorylation, activation of ERK1/2, and neurite outgrowth. Moreover, mutation of the R103 residue of pro-BDNF abrogated its binding to TrkB-Fc but not to p75NTR-Fc. Taken together, these data indicate that pro-BDNF binds to and activates TrkB and could be involved in TrkB-mediated neurotrophic activity in vivo.
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Affiliation(s)
- B Fayard
- Division of Neuropathology, Institute of Pathology, University of Bern, Bern, Switzerland.
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25
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Ahmed Z, Dent RG, Suggate EL, Barrett LB, Seabright RJ, Berry M, Logan A. Disinhibition of neurotrophin-induced dorsal root ganglion cell neurite outgrowth on CNS myelin by siRNA-mediated knockdown of NgR, p75NTR and Rho-A. Mol Cell Neurosci 2005; 28:509-23. [PMID: 15737741 DOI: 10.1016/j.mcn.2004.11.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Revised: 10/20/2004] [Accepted: 11/01/2004] [Indexed: 12/12/2022] Open
Abstract
The presence of multiple axon growth inhibitors may partly explain why central nervous system axons are generally incapable of regenerating after injury. Using RNA interference (RNAi) in dorsal root ganglia neurons (DRGN), we demonstrate siRNA-mediated silencing of components of the inhibitory signalling cascade, including p75NTR, NgR and Rho-A mRNA, of 70%, 100% and 100% of the relevant protein, respectively, while changes in neither protein levels nor cellular immunoreactivity were detected using the relevant scrambled siRNA control sequences. Importantly, after 48 h in culture after siRNA-mediated knockdown of Rho-A, neurite outgrowth was enhanced by 30% compared to that after p75NTR and 50% after NgR silencing. By 3 days, a 5-, 3.5- and 6.5-fold increase in betaIII-tubulin protein levels were observed compared to controls without siRNA after knockdown of p75NTR, NgR and Rho-A, respectively. Together, these results suggest that Rho-A knockdown might be the most effective target for a disinhibition strategy to promote CNS axon regeneration in vivo.
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MESH Headings
- Animals
- Cells, Cultured
- Down-Regulation/drug effects
- Down-Regulation/physiology
- Feedback, Physiological/drug effects
- Feedback, Physiological/physiology
- GPI-Linked Proteins
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/metabolism
- Ganglia, Spinal/ultrastructure
- Myelin Proteins/metabolism
- Myelin Proteins/pharmacology
- Nerve Growth Factors/pharmacology
- Nerve Growth Factors/physiology
- Nerve Regeneration/drug effects
- Nerve Regeneration/physiology
- Neurites/drug effects
- Neurites/metabolism
- Nogo Receptor 1
- RNA, Small Interfering/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptor, Nerve Growth Factor
- Receptors, Cell Surface
- Receptors, Nerve Growth Factor/genetics
- Receptors, Nerve Growth Factor/metabolism
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Tubulin/metabolism
- Up-Regulation/drug effects
- Up-Regulation/physiology
- rhoA GTP-Binding Protein/genetics
- rhoA GTP-Binding Protein/metabolism
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Affiliation(s)
- Zubair Ahmed
- Molecular Neuroscience Group, Department of Medicine, University of Birmingham, 3rd Floor Wolfson Research Laboratories, Queen Elizabeth Medical Centre, Edgbaston, Birmingham B15 2TH, UK.
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26
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Scott ALM, Borisoff JF, Ramer MS. Deafferentation and neurotrophin-mediated intraspinal sprouting: a central role for the p75 neurotrophin receptor. Eur J Neurosci 2005; 21:81-92. [PMID: 15654845 DOI: 10.1111/j.1460-9568.2004.03838.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Axonal plasticity in the adult spinal cord is governed by intrinsic neuronal growth potential and by extracellular cues. The p75 receptor (p75(NTR)) binds growth-promoting neurotrophins (NTs) as well as the common receptor for growth-inhibiting myelin-derived proteins (the Nogo receptor) and so is well situated to gauge the balance of positive and negative influences on axonal plasticity. Using transgenic mice lacking the extracellular NT-binding domain of p75(NTR) (p75-/- mice), we have examined the influence of p75(NTR) on changes in the density of primary afferent (calcitonin gene-related peptide-expressing) and descending monoaminergic (serotonin- and tyrosine hydroxylase-expressing) projections to the dorsal horn after dorsal rhizotomy, with and without concomitant application of exogenous nerve growth factor and NT-3. We found that, in intact p75-/- mice, the axon density of all populations was equal to or less than that in wild-type mice but that rhizotomy-induced intraspinal sprouting was significantly augmented. Monoaminergic axon sprouting was enhanced in both nerve growth factor- and NT-3-treated p75-/- mice compared with similarly treated wild-type mice. Primary afferent sprouting was particularly robust in NT-3-treated p75-/- mice. These in vivo results illustrate the interactions of p75(NTR) with NTs, with their respective tropomyosin-related kinase receptors and with inhibitory myelin-derived molecules. Our findings illustrate the pivotal role of p75(NTR) in spinal axonal plasticity and identify it as a potential therapeutic target for spinal cord injury.
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Affiliation(s)
- Angela L M Scott
- ICORD (International Collaboration on Repair Discoveries), The University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada, V6T 1Z4
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27
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Zhang YH, Nicol GD. NGF-mediated sensitization of the excitability of rat sensory neurons is prevented by a blocking antibody to the p75 neurotrophin receptor. Neurosci Lett 2004; 366:187-92. [PMID: 15276244 DOI: 10.1016/j.neulet.2004.05.042] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 05/12/2004] [Accepted: 05/15/2004] [Indexed: 12/21/2022]
Abstract
Nerve growth factor (NGF) can play a causal role in the initiation of hyperalgesia. Recent work demonstrates that NGF can act directly on nociceptive sensory neurons to augment their sensitivity to a variety of stimuli. Based on the existing literature, it is not clear whether this sensitization is mediated by the high-affinity TrkA receptor or the low-affinity p75 neurotrophin receptor. We examined whether a blocking antibody to the p75 neurotrophin receptor can prevent the NGF-induced enhancement of excitability in capsaicin-sensitive small-diameter sensory neurons that have been isolated from the adult rat. In this report, pretreatment with the p75 blocking antibody completely prevents the NGF-induced increase in the number of action potentials evoked by a ramp of depolarizing current as well as the suppression of a delayed rectifier-type of potassium current(s) in these neurons. Although the sensitization by NGF was blocked, the antibody had no effect on the capacity of ceramide, a putative downstream signaling molecule, to either enhance the excitability or inhibit the potassium current. These results indicate that NGF can increase the excitability of nociceptive sensory neurons through activation of the p75 neurotrophin receptor and its consequent liberation of ceramide from neuronal sphingomyelins.
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Affiliation(s)
- Y H Zhang
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA
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28
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Tsai SJ. Down-regulation of the Trk-B signal pathway: the possible pathogenesis of major depression. Med Hypotheses 2004; 62:215-8. [PMID: 14962629 DOI: 10.1016/s0306-9877(03)00299-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2003] [Accepted: 10/16/2003] [Indexed: 11/23/2022]
Abstract
Major depressive disorder (MDD) is a common mental disease with unknown etiology. Recent studies have suggested that decreased brain-derived neurotrophic factor (BDNF) may be implicated in the pathogenesis of MDD. Instead of a decrease in central BDNF, however, studies utilizing genetic depression animal models have found elevated levels of the factor. In the brain, BDNF exerts its influence chiefly by signaling through tyrosine receptor kinase B (Trk-B). In this report, it is suggested that Trk-B pathway down-regulation may be the major pathogenesis for MDD, while stress, which may reduce central BDNF, acts as a precipitation factor to further dampen central BDNF activity and contribute to the development of depression. Further, several possible mechanisms of Trk-B pathway down-regulation, and the implications for this down-regulation in MDD are discussed.
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Affiliation(s)
- Shih-Jen Tsai
- Department of Psychiatry, Taipei Veterans General Hospital, No. 201, Shih-Pai Road, Sec. 2, 11217, Taipei, Taiwan, ROC.
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29
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Vega JA, García-Suárez O, Germanà A. Vertebrate thymus and the neurotrophin system. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 237:155-204. [PMID: 15380668 DOI: 10.1016/s0074-7696(04)37004-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An immunomodulary role has been proposed for growth factors included in the family of neurotrophins. This is supported by the presence of both neurotrophins and neurotrophin receptors in the immune organs and some immunocompetent cells, the in vitro and in vivo effects of the neurotrophins on the immune cells, and the structural changes of lymphoid organs in mice deficient in neurotrophins and their receptors. The current data strongly indicate that neurotrophins regulate the biology of thymic stromal cells and T cells, including survival, and are involved in the thymic organogenesis. This review compiles the available data about the occurrence and distribution of neurotrophins and their signaling receptors (Trk proteins and p75(NTR)) in the vertebrate thymus and the possible contribution of these molecules to the thymic microenvironment and, therefore, to the T cells differentiation.
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Affiliation(s)
- José A Vega
- Departamento de Morfología y Biología Celular Universidad de Oviedo, 33006 Oviedo, Spain
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30
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Ivanisevic L, Banerjee K, Saragovi HU. Differential cross-regulation of TrkA and TrkC tyrosine kinase receptors with p75. Oncogene 2003; 22:5677-85. [PMID: 12944916 DOI: 10.1038/sj.onc.1206864] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The neurotrophins neurotrophin-3 (NT-3), brain-derived growth factor (BDNF) and nerve growth factor (NGF) bind to the p75 receptor, but each neurotrophin also binds a more selective Trk receptor (e.g. TrkA-NGF and TrkC-NT-3). The biochemical signals following engagement of either Trk or p75 with ligands are well understood, but long-term biological outcomes (trophic, proapoptotic or differentiative) remain unclear because they are cell/tissue specific. For example, Trk receptors are usually trophic but when overexpressed they can be proapoptotic in neuroblastomas and medulloblastomas. We hypothesized that coexpression of Trk and p75 receptors may lead to cross-regulation of signals and different biological outcomes; and used receptor-selective ligands to study cross-regulation by these receptors. We show that in the absence of Trk activation, expression of TrkC is permissive of p75 trophic and differentiation signals induced by p75 ligands, whereas expression of TrkA abolishes trophic and differentiation signals induced by p75 ligands. In contrast, in the presence of Trk activation, p75 ligands can regulate TrkA-mediated survival and TrkC-mediated differentiation. Therefore, a complex homeostasis of p75-selective and Trk-selective signals may determine the fate of cells expressing both receptors.
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Affiliation(s)
- Ljubica Ivanisevic
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC, Canada
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31
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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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32
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Rabin SJ, Bachis A, Mocchetti I. Gangliosides activate Trk receptors by inducing the release of neurotrophins. J Biol Chem 2002; 277:49466-72. [PMID: 12388556 DOI: 10.1074/jbc.m203240200] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We used NIH-3T3 fibroblasts expressing the different Trk receptors to examine whether GM1 ganglioside and its semisynthetic derivative LIGA20 activate various neurotrophin receptors. GM1 induced autophosphorylation of TrkC more potently than TrkA or TrkB receptors. In contrast, LIGA20 activated TrkB tyrosine phosphorylation only. Therefore, Scatchard analysis was performed to determine whether GM1 binds to TrkC. GM1 failed to displace neurotrophin-3 binding, suggesting that this ganglioside does not act as a ligand for Trk receptors. In addition, GM1 failed to induce autophosphorylation of a chimeric receptor consisting of the extracellular domain of the tumor necrosis factor receptor and the intracellular domain of TrkA, suggesting that GM1 does not affect the tyrosine kinase domain. We next determined whether GM1 induces the release of neurotrophins from fibroblast cells. GM1 induced a rapid and significant increase in the amount of neurotrophin-3, but not other neurotrophins. This effect was independent of the presence of Trk because K252a did not prevent GM1-mediated release of neurotrophin-3. Moreover, GM1-mediated TrkC autophosphorylation was blocked by TrkC-IgG (but not TrkB-IgG) receptor bodies, further suggesting that GM1 activates TrkC by inducing the release of neurotrophin-3. This hypothesis was also tested in cultured cerebellar granule cells. GM1 induced neurotrophin-3 (but not brain-derived neurotrophic factor or nerve growth factor) release. In contrast, LIGA20 increased the secretion of brain-derived neurotrophic factor. Our data show that gangliosides may activate different Trk receptors by differentially affecting the release of neurotrophins.
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Affiliation(s)
- Stuart J Rabin
- Department of Neuroscience, Georgetown University Medical Center, Washington, D. C. 20057, USA
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33
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Krüttgen A, Saxena S, Evangelopoulos ME, Weis J. Neurotrophin Receptors and Retrograde Signaling: A Long-Distance Relationship. Neuroembryology Aging 2002. [DOI: 10.1159/000063532] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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34
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Bui NT, König HG, Culmsee C, Bauerbach E, Poppe M, Krieglstein J, Prehn JHM. p75 neurotrophin receptor is required for constitutive and NGF-induced survival signalling in PC12 cells and rat hippocampal neurones. J Neurochem 2002; 81:594-605. [PMID: 12065668 DOI: 10.1046/j.1471-4159.2002.00841.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have previously shown that nerve growth factor (NGF)-induced activation of nuclear factor-kappaB increased neuronal expression of Bcl-xL, an anti-apoptotic Bcl-2 family protein. In the present study we determined the role of the p75 neurotrophin receptor in constitutive and NGF-induced survival signalling. Treatment of rat pheochromocytoma (PC12) cells with a blocking anti-rat p75 antibody or inhibition of p75 expression by antisense oligonucleotides reduced constitutive and NGF-induced bcl-xL expression. Treatment with the blocking anti-p75 antibody also inhibited NGF-induced activation of the survival kinase Akt. Inhibition of phosphatidylinositol-3-kinase (PI3 kinase) activity or overexpression of a dominant-negative mutant of Akt kinase inhibited NGF-induced nuclear factor-kappaB activation. Activation of Akt kinase by NGF was also observed in PC12nnr5 cells and cultured rat hippocampal neurones which both lack significant TrkA expression. Treatment of hippocampal neurones with the blocking anti-p75 antibody inhibited constitutive and NGF-induced Bcl-xL expression, activation of Akt, and blocked the protective effect of NGF against excitotoxic and apoptotic injury. Our data suggest that the p75 neurotrophin receptor mediates constitutive and NGF-induced survival signalling in PC12 cells and hippocampal neurones, and that these effects are mediated via the PI3-kinase pathway.
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MESH Headings
- Animals
- Antibodies/pharmacology
- Cell Survival/drug effects
- Cells, Cultured
- Cytoprotection/drug effects
- Enzyme Activation/drug effects
- Hippocampus/cytology
- Hippocampus/drug effects
- Hippocampus/metabolism
- Mice
- Mice, Inbred BALB C
- Mice, Knockout
- NF-kappa B/metabolism
- Nerve Growth Factor/pharmacology
- Neurons/cytology
- Neurons/drug effects
- Neurons/metabolism
- Oligonucleotides, Antisense/pharmacology
- PC12 Cells
- Pheochromocytoma/metabolism
- Phosphatidylinositol 3-Kinases/metabolism
- Protein Serine-Threonine Kinases
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-akt
- Proto-Oncogene Proteins c-bcl-2/biosynthesis
- RNA, Messenger/biosynthesis
- Rats
- Rats, Inbred F344
- Receptor, Nerve Growth Factor
- Receptor, trkA/metabolism
- Receptors, Nerve Growth Factor/antagonists & inhibitors
- Receptors, Nerve Growth Factor/genetics
- Receptors, Nerve Growth Factor/metabolism
- Signal Transduction/drug effects
- Signal Transduction/physiology
- bcl-X Protein
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Affiliation(s)
- Nguyen Truc Bui
- Interdisciplinary Center for Clinical Research, Research Group 'Apoptosis and Cell Death', Faculty of Medicine, Westphalian Wilhelms-University, Münster, Germany
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35
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Anderson RA, Robinson LLL, Brooks J, Spears N. Neurotropins and their receptors are expressed in the human fetal ovary. J Clin Endocrinol Metab 2002; 87:890-7. [PMID: 11836338 DOI: 10.1210/jcem.87.2.8221] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Mammalian ovarian development is characterized by a sequential pattern of mitotic proliferation of oogonia, initiation then arrest of meiosis, and primordial follicle formation. The factors regulating these processes are poorly understood. The neurotropins are survival and differentiation factors in the nervous system, acting via high affinity receptors of the trk protooncogene family and the low affinity p75 nerve growth factor receptor, and have also been described in the rodent ovary, where changes in NT4/TrkB gene expression have been detected at the time of primordial follicle formation. There are no data on neurotropin expression in the normal human ovary. We have investigated the expression and localization of neurotropins and their receptors in the midtrimester human fetal ovary (13-21 wk gestation). Expression of mRNA for neurotropins and their receptors was detected by RT-PCR. Clusters of oogonia were found to be the predominant site of NT4 mRNA expression using in situ hybridization. However, at later gestations granulosa cells of primordial follicles showed increased expression, with lesser expression in the enclosed oocytes. NT4 protein was also localized to the granulosa cells by immunohistochemistry and at earlier developmental stages to epithelioid cells, which were mingled with clusters of oogonia not expressing NT4. TrkB receptor protein was localized by immunohistochemistry to germ cells at all gestations examined. The p75 nerve growth factor receptor protein was exclusively expressed in the ovarian stroma. These data demonstrate the expression of neurotropins and their receptors within the human fetal ovary. Developmental changes in the pattern of expression of NT4 around the time of primordial follicle formation suggest that neurotropins may be involved in signaling between somatic cells and germ cells at this crucial stage of ovarian development.
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Affiliation(s)
- Richard A Anderson
- Medical Research Council Human Reproductive Sciences Unit, Center for Reproductive Biology, University of Edinburgh, Edinburgh, United Kingdom EH3 9ET.
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36
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Esposito D, Patel P, Stephens RM, Perez P, Chao MV, Kaplan DR, Hempstead BL. The cytoplasmic and transmembrane domains of the p75 and Trk A receptors regulate high affinity binding to nerve growth factor. J Biol Chem 2001; 276:32687-95. [PMID: 11435417 DOI: 10.1074/jbc.m011674200] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Ligand-induced receptor oligomerization is an established mechanism for receptor-tyrosine kinase activation. However, numerous receptor-tyrosine kinases are expressed in multicomponent complexes with other receptors that may signal independently or alter the binding characteristics of the receptor-tyrosine kinase. Nerve growth factor (NGF) interacts with two structurally unrelated receptors, the Trk A receptor-tyrosine kinase and p75, a tumor necrosis factor receptor family member. Each receptor binds independently to NGF with predominantly low affinity (K(d) = 10(-9) m), but they produce high affinity binding sites (K(d) = 10(-11) m) upon receptor co-expression. Here we provide evidence that the number of high affinity sites is regulated by the ratio of the two receptors and by specific domains of Trk A and p75. Co-expression of Trk A containing mutant transmembrane or cytoplasmic domains with p75 yielded reduced numbers of high affinity binding sites. Similarly, co-expression of mutant p75 containing altered transmembrane and cytoplasmic domains with Trk A also resulted in predominantly low affinity binding sites. Surprisingly, extracellular domain mutations of p75 that abolished NGF binding still generated high affinity binding with Trk A. These results indicate that the transmembrane and cytoplasmic domains of Trk A and p75 are responsible for high affinity site formation and suggest that p75 alters the conformation of Trk A to generate high affinity NGF binding.
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Affiliation(s)
- D Esposito
- Division of Hematology, Weill Medical College of Cornell University, New York, New York 10021, USA
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37
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Mischel PS, Smith SG, Vining ER, Valletta JS, Mobley WC, Reichardt LF. The extracellular domain of p75NTR is necessary to inhibit neurotrophin-3 signaling through TrkA. J Biol Chem 2001; 276:11294-301. [PMID: 11150291 PMCID: PMC2693057 DOI: 10.1074/jbc.m005132200] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The TrkA receptor is activated primarily by nerve growth factor (NGF), but it can also be activated by high concentrations of neurotrophin 3 (NT-3). The pan-neurotrophin receptor p75(NTR) strongly inhibits activation of TrkA by NT-3 but not by NGF. To examine the role of p75(NTR) in regulating the specificity of TrkA signaling, we expressed both receptors in Xenopus oocytes. Application of NGF or NT-3 to oocytes expressing TrkA alone resulted in efflux of (45)Ca(2+) by a phospholipase C-gamma-dependent pathway. Coexpression of p75(NTR) with TrkA inhibited (45)Ca(2+) efflux in response to NT-3 but not NGF. The inhibitory effect on NT-3 activation of TrkA increased with increasing expression of p75(NTR). Coexpression of a truncated p75(NTR) receptor lacking all but the first 9 amino acids of the cytoplasmic domain inhibited NT-3 stimulation of (45)Ca(2+) efflux, whereas coexpression of an epidermal growth factor receptor/p75(NTR) chimera (extracellular domain of epidermal growth factor receptor with transmembrane and cytoplasmic domains of p75(NTR)) did not inhibit NT-3 signaling through TrkA. These studies demonstrated that the extracellular domain of p75(NTR) was necessary to inhibit NT-3 signaling through TrkA. Remarkably, p75(NTR) binding to NT-3 was not required to prevent signaling through TrkA, since occupying p75(NTR) with brain-derived neurotrophic factor or anti-p75 antibody (REX) did not rescue the ability of NT-3 to activate (45)Ca(2+) efflux. These data suggested a physical association between TrkA and p75(NTR). Documenting this physical interaction, we showed that p75(NTR) and TrkA could be coimmunoprecipitated from Xenopus oocytes. Our results suggest that the interaction of these two receptors on the cell surface mediated the inhibition of NT-3-activated signaling through TrkA.
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Affiliation(s)
- P S Mischel
- Departments of Pathology and Laboratory Medicine, UCLA, Los Angeles, California 90095-1732, USA.
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