1
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Uju CN, Unniappan S. Growth factors and female reproduction in vertebrates. Mol Cell Endocrinol 2024; 579:112091. [PMID: 37863469 DOI: 10.1016/j.mce.2023.112091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 10/05/2023] [Accepted: 10/13/2023] [Indexed: 10/22/2023]
Abstract
Female reproductive efficiency is influenced by the outcomes of various processes, including folliculogenesis, apoptosis, response to gonadotropin signaling, oocyte maturation, and ovulation. The role of hormones in regulating these processes and other reproductive activities has been well established. It is becoming increasingly evident that in addition to well-characterized hormones, growth factors play vital roles in regulating some of these reproductive activities. Growth factors and their receptors are widely distributed in vertebrate ovaries at different stages of ovarian development, indicating their involvement in intraovarian reproductive functions. In the ovary, cell surface receptors allow growth factors to regulate intraovarian reproductive activities. Understanding these actions in the reproductive axis would provide a tool to target growth factors and/or their receptors to yield desirable reproductive outcomes. These include enrichment of in vitro maturation and fertilization culture media, and management of infertility. This review discusses some widely characterized growth factors belonging to the TGF, EGF, IGF, FGF, and BDNF family of peptides and their role in female reproduction in vertebrates, with a focus on mammals.
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Affiliation(s)
- Chinelo N Uju
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5B4, Canada
| | - Suraj Unniappan
- Laboratory of Integrative Neuroendocrinology, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5B4, Canada.
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2
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Sleigh JN, Villarroel-Campos D, Surana S, Wickenden T, Tong Y, Simkin RL, Vargas JNS, Rhymes ER, Tosolini AP, West SJ, Zhang Q, Yang XL, Schiavo G. Boosting peripheral BDNF rescues impaired in vivo axonal transport in CMT2D mice. JCI Insight 2023; 8:e157191. [PMID: 36928301 PMCID: PMC10243821 DOI: 10.1172/jci.insight.157191] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 03/15/2023] [Indexed: 03/18/2023] Open
Abstract
Gain-of-function mutations in the housekeeping gene GARS1, which lead to the expression of toxic versions of glycyl-tRNA synthetase (GlyRS), cause the selective motor and sensory pathology characterizing Charcot-Marie-Tooth disease (CMT). Aberrant interactions between GlyRS mutants and different proteins, including neurotrophin receptor tropomyosin receptor kinase receptor B (TrkB), underlie CMT type 2D (CMT2D); however, our pathomechanistic understanding of this untreatable peripheral neuropathy remains incomplete. Through intravital imaging of the sciatic nerve, we show that CMT2D mice displayed early and persistent disturbances in axonal transport of neurotrophin-containing signaling endosomes in vivo. We discovered that brain-derived neurotrophic factor (BDNF)/TrkB impairments correlated with transport disruption and overall CMT2D neuropathology and that inhibition of this pathway at the nerve-muscle interface perturbed endosome transport in wild-type axons. Accordingly, supplementation of muscles with BDNF, but not other neurotrophins, completely restored physiological axonal transport in neuropathic mice. Together, these findings suggest that selectively targeting muscles with BDNF-boosting therapies could represent a viable therapeutic strategy for CMT2D.
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Affiliation(s)
- James N. Sleigh
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
- UK Dementia Research Institute, University College London (UCL), London, United Kingdom
| | - David Villarroel-Campos
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Sunaina Surana
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
- UK Dementia Research Institute, University College London (UCL), London, United Kingdom
| | - Tahmina Wickenden
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Yao Tong
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Rebecca L. Simkin
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Jose Norberto S. Vargas
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Elena R. Rhymes
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | - Andrew P. Tosolini
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
| | | | - Qian Zhang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Xiang-Lei Yang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, California, USA
| | - Giampietro Schiavo
- Department of Neuromuscular Diseases and UCL Queen Square Motor Neuron Disease Centre, UCL Queen Square Institute of Neurology, and
- UK Dementia Research Institute, University College London (UCL), London, United Kingdom
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3
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Muheim CM, Singletary KG, Frank MG. A chemical-genetic investigation of BDNF-NtrkB signaling in mammalian sleep. Sleep 2021; 45:6372412. [PMID: 34537852 DOI: 10.1093/sleep/zsab237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 08/15/2021] [Indexed: 11/12/2022] Open
Abstract
STUDY OBJECTIVES The neurotrophin brain derived neurotrophic factor (BDNF) is hypothesized to be a molecular mediator of mammalian sleep homeostasis. This hypothesis is supported by correlational findings and results obtained from pharmacology. BDNF binds with high affinity to the membrane bound receptor Neurotrophin Tyrosine Kinase Receptor B (NtrkB), which triggers several intracellular signaling cascades. It is therefore possible that BDNF's role in sleep homeostasis is mediated via NtrkB. We examined this hypothesis using a chemical-genetic technique that allows for rapid and selective inhibition of NtrkB in vivo. METHODS We used mutant mice bearing a point mutation in the NtrkB that allows for selective and reversible inactivation in the presence of a small binding molecule (1-NM-PP1). Using a cross-over design, we determined the effects of NtrkB inhibition on baseline sleep architecture and sleep homeostasis. RESULTS We find that NtrkB inhibition reduced REM sleep time and increased state-transitions but had no effect on sleep homeostasis. CONCLUSIONS These findings suggest that BDNF-NtrkB receptor signaling has relatively subtle roles in sleep architecture, but no role in sleep homeostasis.
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Affiliation(s)
- Christine M Muheim
- Washington State University Spokane, Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Pharmaceutical and Biomedical Science Building 230, 412 E. Spokane Falls Blvd, Spokane WA 99202, USA
| | - Kristan G Singletary
- Washington State University Spokane, Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Pharmaceutical and Biomedical Science Building 230, 412 E. Spokane Falls Blvd, Spokane WA 99202, USA
| | - Marcos G Frank
- Washington State University Spokane, Department of Translational Medicine and Physiology, Elson S. Floyd College of Medicine, Pharmaceutical and Biomedical Science Building 230, 412 E. Spokane Falls Blvd, Spokane WA 99202, USA.,WSU Health Sciences Spokane, Steve Gleason Institute for Neuroscience, 412 E. Spokane Falls Blvd, Spokane, WA 99202, USA
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4
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Lau CG, Zhang H, Murthy VN. Deletion of TrkB in parvalbumin interneurons alters cortical neural dynamics. J Cell Physiol 2021; 237:949-964. [PMID: 34491578 PMCID: PMC8810709 DOI: 10.1002/jcp.30571] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 11/25/2022]
Abstract
Signaling by neurotrophins such as the brain‐derived neurotrophic factor (BDNF) is known to modulate development of interneurons, but the circuit effects of this modulation remain unclear. Here, we examined the impact of deleting TrkB, a BDNF receptor, in parvalbumin‐expressing (PV) interneurons on the balance of excitation and inhibition (E‐I) in cortical circuits. In the mouse olfactory cortex, TrkB deletion impairs multiple aspects of PV neuronal function including synaptic excitation, intrinsic excitability, and the innervation pattern of principal neurons. Impaired PV cell function resulted in aberrant spiking patterns in principal neurons in response to stimulation of sensory inputs. Surprisingly, dampened PV neuronal function leads to a paradoxical decrease in overall excitability in cortical circuits. Our study demonstrates that, by modulating PV circuit plasticity and development, TrkB plays a critical role in shaping the evoked pattern of activity in a cortical network.
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Affiliation(s)
- Chunyue Geoffrey Lau
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China.,Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
| | - Huiqi Zhang
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China
| | - Venkatesh N Murthy
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
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5
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Tawarayama H, Inoue-Yanagimachi M, Himori N, Nakazawa T. Glial cells modulate retinal cell survival in rotenone-induced neural degeneration. Sci Rep 2021; 11:11159. [PMID: 34045544 PMCID: PMC8159960 DOI: 10.1038/s41598-021-90604-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 05/12/2021] [Indexed: 12/21/2022] Open
Abstract
Administration of the mitochondrial complex I inhibitor rotenone provides an excellent model to study the pathomechanism of oxidative stress-related neural degeneration diseases. In this study, we examined the glial roles in retinal cell survival and degeneration under the rotenone-induced oxidative stress condition. Mouse-derived Müller, microglial (BV-2), and dissociated retinal cells were used for in vitro experiments. Gene expression levels and cell viability were determined using quantitative reverse transcription-polymerase chain reaction and the alamarBlue assay, respectively. Conditioned media were prepared by stimulating glial cells with rotenone. Retinal ganglion cells (RGCs) and inner nuclear layer (INL) were visualized on rat retinal sections by immunohistochemistry and eosin/hematoxylin, respectively. Rotenone dose-dependently induced glial cell death. Treatment with rotenone or rotenone-stimulated glial cell-conditioned media altered gene expression of growth factors and inflammatory cytokines in glial cells. The viability of dissociated retinal cells significantly increased upon culturing in media conditioned with rotenone-stimulated or Müller cell-conditioned media-stimulated BV-2 cells. Furthermore, intravitreal neurotrophin-5 administration prevented the rotenone-induced reduction of RGC number and INL thickness in rats. Thus, glial cells exerted both positive and negative effects on retinal cell survival in rotenone-induced neural degeneration via altered expression of growth factors, especially upregulation of microglia-derived Ntf5, and proinflammatory cytokines.
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Affiliation(s)
- Hiroshi Tawarayama
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan.,Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan
| | - Maki Inoue-Yanagimachi
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Noriko Himori
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan
| | - Toru Nakazawa
- Department of Ophthalmology, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Aoba-ku, Sendai, 980-8574, Japan. .,Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan. .,Collaborative Program of Ophthalmic Drug Discovery, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan. .,Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan. .,Department of Ophthalmic Imaging and Information Analytics, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan.
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6
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The biophysical basis of receptor tyrosine kinase ligand functional selectivity: Trk-B case study. Biochem J 2021; 477:4515-4526. [PMID: 33094812 DOI: 10.1042/bcj20200671] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/19/2020] [Accepted: 10/22/2020] [Indexed: 01/08/2023]
Abstract
Tropomyosin receptor kinase B (Trk-B) belongs to the second largest family of membrane receptors, Receptor Tyrosine Kinases (RTKs). Trk-B is known to interact with three different neurotrophins: Brain-Derived Neurotrophic Factor (BDNF), Neurotrophin-4 (NT-4), and Neurotrophin-3 (NT-3). All three neurotrophins are involved in survival and proliferation of neuronal cells, but each induces distinct signaling through Trk-B. We hypothesize that the different biological effects correlate with differences in the interactions between the Trk-B receptors, when bound to different ligands, in the plasma membrane. To test this hypothesis, we use quantitative FRET to characterize Trk-B dimerization in response to NT-3 and NT-4 in live cells, and compare it to the previously published data for Trk-B in the absence and presence of BDNF. Our study reveals that the distinct Trk-B signaling outcomes are underpinned by both different configurations and different stabilities of the three ligand-bound Trk-B dimers in the plasma membrane.
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7
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Martín-Rodríguez C, Song M, Anta B, González-Calvo FJ, Deogracias R, Jing D, Lee FS, Arevalo JC. TrkB deubiquitylation by USP8 regulates receptor levels and BDNF-dependent neuronal differentiation. J Cell Sci 2020; 133:jcs247841. [PMID: 33288548 PMCID: PMC7774901 DOI: 10.1242/jcs.247841] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 11/13/2020] [Indexed: 01/04/2023] Open
Abstract
Ubiquitylation of receptor tyrosine kinases (RTKs) regulates both the levels and functions of these receptors. The neurotrophin receptor TrkB (also known as NTRK2), a RTK, is ubiquitylated upon activation by brain-derived neurotrophic factor (BDNF) binding. Although TrkB ubiquitylation has been demonstrated, there is a lack of knowledge regarding the precise repertoire of proteins that regulates TrkB ubiquitylation. Here, we provide mechanistic evidence indicating that ubiquitin carboxyl-terminal hydrolase 8 (USP8) modulates BDNF- and TrkB-dependent neuronal differentiation. USP8 binds to the C-terminus of TrkB using its microtubule-interacting domain (MIT). Immunopurified USP8 deubiquitylates TrkB in vitro, whereas knockdown of USP8 results in enhanced ubiquitylation of TrkB upon BDNF treatment in neurons. As a consequence of USP8 depletion, TrkB levels and its activation are reduced. Moreover, USP8 protein regulates the differentiation and correct BDNF-dependent dendritic formation of hippocampal neurons in vitro and in vivo We conclude that USP8 positively regulates the levels and activation of TrkB, modulating BDNF-dependent neuronal differentiation.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Carlos Martín-Rodríguez
- Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain
- Institute of Biomedical Research of Salamanca, 37007 Salamanca, Spain
| | - Minseok Song
- Department of Life Sciences, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Korea
| | - Begoña Anta
- Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain
- Institute of Biomedical Research of Salamanca, 37007 Salamanca, Spain
| | - Francisco J González-Calvo
- Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain
| | - Rubén Deogracias
- Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain
| | - Deqiang Jing
- Department of Psychiatry, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA
| | - Francis S Lee
- Department of Psychiatry, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10065, USA
| | - Juan Carlos Arevalo
- Departmento de Biología Celular y Patología, Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca 37007, Spain
- Institute of Biomedical Research of Salamanca, 37007 Salamanca, Spain
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8
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Hernandez-Echeagaray E. The role of the TrkB-T1 receptor in the neurotrophin-4/5 antagonism of brain-derived neurotrophic factor on corticostriatal synaptic transmission. Neural Regen Res 2020; 15:1973-1976. [PMID: 32394943 PMCID: PMC7716028 DOI: 10.4103/1673-5374.282224] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
This manuscript reviews the function and fundamental characteristics of the neurotrophins and their receptors to introduce the reader to the differential effects exhibited by the neurotrophins; brain-derived neurotrophic factor and neurotrophin 4/5 when acted together after sequential presentation. The neurotrophin 4/5 exhibits an inhibitory action on the modulatory effect of brain-derived neurotrophic factor in corticostriatal synapses when they are administered sequentially (brain-derived neurotrophic factor to neurotrophin 4/5). This inhibitory effect has not been previously documented and is relevant for these neurotrophins as both of them stimulate the TrkB receptor. The additive effect of these neurotrophins is also discussed and occurs when neurotrophin 4/5 exposure is followed by brain-derived neurotrophic factor in a mouse model of striatal degeneration. Occlusive and additive effects of both neurotrophins are accompanied by changes in the expression of the TrkB receptor isoforms, specifically TrkB-T1 and TrkB-FL, as well as differences in phosphorylation levels of the TrkB receptor. The results of the experiments described raise several questions to inquire about the role that TrkB-T1 receptor plays in striatal physiology, as well as the functional relevance of the interaction of brain-derived neurotrophic factor and neurotrophin 4/5 in the brain and more specifically at the striatal circuits in normal as well as pathological conditions.
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9
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Torres-Cruz FM, Mendoza E, Vivar-Cortés IC, García-Sierra F, Hernández-Echeagaray E. Do BDNF and NT-4/5 exert synergistic or occlusive effects on corticostriatal transmission in a male mouse model of Huntington's disease? J Neurosci Res 2019; 97:1665-1677. [PMID: 31392756 DOI: 10.1002/jnr.24507] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/12/2019] [Accepted: 07/22/2019] [Indexed: 12/14/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5 (NT-4/5) are trophic factors belonging to the neurotrophin family; in addition to their trophic role, both neurotrophins play an important role in modulating corticostriatal synaptic transmission. Failures in BDNF supply and mitochondrial dysfunction are among the factors involved in the striatal degeneration that occurs in Huntington's disease (HD). While the effects of BDNF have been widely studied in striatal degeneration, the role of NT-4/5 has been less addressed. NT-4/5 does not appear to exert effects similar to those of BDNF in HD. The physiological roles of these molecules in corticostriatal transmission have been evaluated separately, and we have demonstrated that sequential exposure to both neurotrophins results in different modulatory effects on corticostriatal transmission depending on the exposure order. In the present study, we evaluated the effects of BDNF followed by NT-4/5 or NT-4/5 followed by BDNF on corticostriatal synaptic transmission with field recordings in a male mouse model of HD produced by in vivo treatment with the mitochondrial toxin 3-nitropropionic acid. Here, we show that these neurotrophins elicit an antagonistic or synergistic effect that depends on the activation of the truncated isoform or the stimulation of the full-length isoform of the tropomyosin receptor kinase B.
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Affiliation(s)
- Francisco M Torres-Cruz
- Laboratorio de Neurofisiología del desarrollo y la neurodegeneración, Unidad de Investigación en Biomedicina FES-Iztacala, Universidad Nacional Autónoma de México, México, México
| | - Ernesto Mendoza
- Laboratorio de Neurofisiología del desarrollo y la neurodegeneración, Unidad de Investigación en Biomedicina FES-Iztacala, Universidad Nacional Autónoma de México, México, México
| | - Israel C Vivar-Cortés
- Laboratorio de Neurofisiología del desarrollo y la neurodegeneración, Unidad de Investigación en Biomedicina FES-Iztacala, Universidad Nacional Autónoma de México, México, México
| | | | - Elizabeth Hernández-Echeagaray
- Laboratorio de Neurofisiología del desarrollo y la neurodegeneración, Unidad de Investigación en Biomedicina FES-Iztacala, Universidad Nacional Autónoma de México, México, México
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10
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Torres-Cruz FM, César Vivar-Cortés I, Moran I, Mendoza E, Gómez-Pineda V, García-Sierra F, Hernández-Echeagaray E. NT-4/5 antagonizes the BDNF modulation of corticostriatal transmission: Role of the TrkB.T1 receptor. CNS Neurosci Ther 2019; 25:621-631. [PMID: 30666798 PMCID: PMC6488875 DOI: 10.1111/cns.13091] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 11/14/2018] [Accepted: 11/19/2018] [Indexed: 12/14/2022] Open
Abstract
Neurotrophins are related to survival, growth, differentiation and neurotrophic maintenance as well as modulation of synaptic transmission in different regions of the nervous system. BDNF effects have been studied in the striatum due to the trophic role of BDNF in medium spiny neurons; however, less is known about the effects of NT‐4/5, which is also present in the striatum and activates the TrkB receptor along with BDNF. If both neurotrophins are present in the striatum, the following question arises: What role do they play in striatal physiology? Thus, the aim of this study was to determine the physiological effect of the sequential application and coexistence of BDNF and NT‐4/5 on the modulation of corticostriatal synapses. Our data demonstrated that neurotrophins exhibit differential effects depending on exposure order. BDNF did not modify NT‐4/5 effect; however, NT‐4/5 inhibited the effects of BDNF. Experiments carried out in COS‐7 cells to understand the mechanisms of this antagonism, indicated that NT‐4/5 exerts its inhibitory effect on BDNF by upregulating the TrkB.T1 and downregulating the TrkB‐FL isoforms of the TrkB receptor.
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Affiliation(s)
- Francisco M Torres-Cruz
- Laboratorio de Neurofisiología del Desarrollo y la Neurodegeneración, UBIMED, FES-Iztacala, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Israel César Vivar-Cortés
- Laboratorio de Neurofisiología del Desarrollo y la Neurodegeneración, UBIMED, FES-Iztacala, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Isaac Moran
- Laboratorio de Neurofisiología del Desarrollo y la Neurodegeneración, UBIMED, FES-Iztacala, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Ernesto Mendoza
- Laboratorio de Neurofisiología del Desarrollo y la Neurodegeneración, UBIMED, FES-Iztacala, Universidad Nacional Autónoma de México, Ciudad de México, México
| | - Victor Gómez-Pineda
- Laboratorio de Neurofisiología del Desarrollo y la Neurodegeneración, UBIMED, FES-Iztacala, Universidad Nacional Autónoma de México, Ciudad de México, México
| | | | - Elizabeth Hernández-Echeagaray
- Laboratorio de Neurofisiología del Desarrollo y la Neurodegeneración, UBIMED, FES-Iztacala, Universidad Nacional Autónoma de México, Ciudad de México, México
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11
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Zhang R, Zhang Y, Yi S. Identification of critical growth factors for peripheral nerve regeneration. RSC Adv 2019; 9:10760-10765. [PMID: 35515307 PMCID: PMC9062509 DOI: 10.1039/c9ra01710k] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 03/26/2019] [Indexed: 12/17/2022] Open
Abstract
Growth factors are essential for the repair and regeneration of tissues and organs, including injured peripheral nerves. However, the expression changes of growth factors during peripheral nerve regeneration have not been fully elucidated. To obtain a global view of alternations of growth factors during the regeneration process, we explored previously achieved sequencing data of rat sciatic nerve stumps at 0 h, 1 d, 4 d, 7 d, and 14 d after nerve crush injury and screened differentially expressed upstream growth factors using Ingenuity Pathway Analysis (IPA) bioinformatic software. Differentially expressed growth factors were then subjected to Gene Ontology (GO) annotation and Kyoto Enrichment of Genes and Genomes (KEGG) pathway analysis. Regulatory networks of the differentially expressed growth factors in axon growth-related biological processes were constructed. Pivotal growth factors involved in axon growth were identified and validated by qRT-PCR. Our current study identified differentially expressed growth factors in the injured nerve stumps after peripheral nerve injury, discovered key growth factors for axon growth and nerve regeneration, and might facilitate the discovery of potential therapeutic targets of peripheral nerve injury. Growth factors are essential for the repair and regeneration of tissues and organs, including injured peripheral nerves.![]()
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Affiliation(s)
- Ruirui Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education
- Co-innovation Center of Neuroregeneration
- Nantong University
- Nantong
- China
| | - Yan Zhang
- Department of Respiratory and Critical Care Medicine
- Affiliated Hospital of Nantong University
- Nantong
- China
| | - Sheng Yi
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education
- Co-innovation Center of Neuroregeneration
- Nantong University
- Nantong
- China
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12
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Therapeutic Potential of a Combination of Electroacupuncture and TrkB-Expressing Mesenchymal Stem Cells for Ischemic Stroke. Mol Neurobiol 2018; 56:157-173. [PMID: 29682700 DOI: 10.1007/s12035-018-1067-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 04/08/2018] [Indexed: 12/15/2022]
Abstract
We prepared and grafted tropomyosin receptor kinase B (TrkB) gene-transfected mesenchymal stem cells (TrkB-MSCs) into the ischemic penumbra and investigated whether electroacupuncture (EA) treatment could promote functional recovery from ischemic stroke. For the behavioral test, TrkB-MSCs+EA resulted in significantly improved motor function compared to that obtained with MSCs+EA or TrkB-MSCs alone. At 30 days after middle cerebral artery occlusion (MCAO), the largest number of grafted MSCs was detected in the TrkB-MSC+EA group. Some differentiation into immature neuroblasts and astrocytes was detected; however, only a few mature neuron-like cells were found. Compared to other treatments, TrkB-MSCs+EA upregulated the expression of mature brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5 (NT4) and induced the activation of TrkB receptor and its transcription factor cAMP response element-binding protein (CREB). At 60 days after MCAO, EA highly promoted the differentiation of TrkB-MSCs into mature neuron-like cells compared to the effect in MSCs. A selective TrkB antagonist, ANA-12, reverted the effect of TrkB-MSCs+EA in motor function recovery and survival of grafted MSCs. Our results suggest that EA combined with grafted TrkB-MSCs promotes the expression of BDNF and NT4, induces the differentiation of TrkB-MSCs, and improves motor function. TrkB-MSCs could serve as effective therapeutic agents for ischemic stroke if used in combination with BDNF/NT4-inducing therapeutic approaches.
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Yang M, Pan Z, Huang K, Büsche G, Feuerhake F, Chaturvedi A, Nie D, Heuser M, Thol F, von Neuhoff N, Ganser A, Li Z. Activation of TRKA receptor elicits mastocytosis in mice and is involved in the development of resistance to KIT-targeted therapy. Oncotarget 2017; 8:73871-73883. [PMID: 29088753 PMCID: PMC5650308 DOI: 10.18632/oncotarget.18027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 05/08/2017] [Indexed: 12/03/2022] Open
Abstract
The neurotrophins (NTs) play a key role in neuronal survival and maintenance. The TRK (tropomyosin-related kinase) tyrosine kinase receptors (TRKA, TRKB, TRKC) are high affinity receptors for NTs. There is increasing data demonstrating an important role of the TRK family in cancer initiation and progression. NTs have been known for many years to promote chemotaxis, maturation, and survival of mast cells. However, the role of NT signaling in the pathogenesis of mastocytosis is not well understood. In this study, we demonstrate that activation of TRKA by its ligand nerve growth factor (NGF) is potent to trigger a disease in mice with striking similarities to human systemic mastocytosis (SM). Moreover, activation of TRKA by NGF strongly rescues KIT inhibition-induced cell death of mast cell lines and primary mast cells from patients with SM, and this rescue effect can be efficiently blocked by entrectinib (a new pan TRK specific inhibitor). HMC-1 mast cell leukemia cells that are resistant to KIT inhibition induced by TRKA activation show reactivation of MAPK/ERK (extracellular signal-regulated kinase) and strong upregulation of early growth response 3 (EGR3), suggesting an important role of MAPK-EGR3 axis in the development of resistance to KIT inhibition. Targeting both TRK and KIT significantly prolongs survival of mice xenotransplanted with HMC-1 cells compared with targeting KIT alone. Thus, these data strongly suggest that TRKA signaling can improve neoplastic mast cell fitness. This might explain at least in part why treatment with KIT inhibitors alone so far has been disappointing in most published clinical trials for mastocytosis. Our data suggest that targeting both KIT and TRKs might improve efficacy of molecular therapy in SM with KIT mutations.
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Affiliation(s)
- Min Yang
- Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - Zengkai Pan
- Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - Kezhi Huang
- Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany.,Department of Hematology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Guntram Büsche
- Institute of Pathology, Hannover Medical School, Hannover, Germany
| | | | - Anuhar Chaturvedi
- Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - Danian Nie
- Department of Hematology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Michael Heuser
- Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - Felicitas Thol
- Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - Nils von Neuhoff
- Institute of Pathology, Hannover Medical School, Hannover, Germany
| | - Arnold Ganser
- Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
| | - Zhixiong Li
- Department of Hematology, Hemostasis, Oncology, and Stem Cell Transplantation, Hannover Medical School, Hannover, Germany
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14
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Adachi M, Autry AE, Mahgoub M, Suzuki K, Monteggia LM. TrkB Signaling in Dorsal Raphe Nucleus is Essential for Antidepressant Efficacy and Normal Aggression Behavior. Neuropsychopharmacology 2017; 42:886-894. [PMID: 27634357 PMCID: PMC5312065 DOI: 10.1038/npp.2016.201] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/05/2016] [Accepted: 09/02/2016] [Indexed: 01/09/2023]
Abstract
Brain-derived neurotrophic factor (BDNF) and its high affinity receptor, tropomyosin receptor kinase B (TrkB), have important roles in neural plasticity and are required for antidepressant efficacy. Studies examining the role of BDNF-TrkB signaling in depression and antidepressant efficacy have largely focused on the limbic system, leaving it unclear whether this signaling is important in other brain regions. BDNF and TrkB are both highly expressed in the dorsal raphe nucleus (DRN), a brain region that has been suggested to have a role in depression and antidepressant action, although it is unknown whether BDNF and TrkB in the dorsal raphe nucleus are involved in these processes. We combined the adeno-associated virus (AAV) with the Cre-loxP site-specific recombination system to selectively knock down either Bdnf or TrkB in the DRN. These mice were then characterized in several behavioral paradigms including measures of depression-related behavior and antidepressant efficacy. We show that knockdown of TrkB, but not Bdnf, in the DRN results in loss of antidepressant efficacy and increased aggression-related behavior. We also show that knockdown of TrkB or Bdnf in this brain region does not have an impact on weight, activity levels, anxiety, or depression-related behaviors. These data reveal a critical role for TrkB signaling in the DRN in mediating antidepressant responses and normal aggression behavior. The results also suggest a non-cell autonomous role for BDNF in the DRN in mediating antidepressant efficacy.
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Affiliation(s)
- Megumi Adachi
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Anita E Autry
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Melissa Mahgoub
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Kanzo Suzuki
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Lisa M Monteggia
- Department of Neuroscience, The University of Texas Southwestern Medical Center, Dallas, TX, USA,Department of Neuroscience, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, NB4, Dallas, TX 75390-9111, USA. Tel: +214 648 5548, Fax: +214 648 4947, E-mail:
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15
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Pramanik S, Sulistio YA, Heese K. Neurotrophin Signaling and Stem Cells-Implications for Neurodegenerative Diseases and Stem Cell Therapy. Mol Neurobiol 2016; 54:7401-7459. [PMID: 27815842 DOI: 10.1007/s12035-016-0214-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 10/11/2016] [Indexed: 02/07/2023]
Abstract
Neurotrophins (NTs) are members of a neuronal growth factor protein family whose action is mediated by the tropomyosin receptor kinase (TRK) receptor family receptors and the p75 NT receptor (p75NTR), a member of the tumor necrosis factor (TNF) receptor family. Although NTs were first discovered in neurons, recent studies have suggested that NTs and their receptors are expressed in various types of stem cells mediating pivotal signaling events in stem cell biology. The concept of stem cell therapy has already attracted much attention as a potential strategy for the treatment of neurodegenerative diseases (NDs). Strikingly, NTs, proNTs, and their receptors are gaining interest as key regulators of stem cells differentiation, survival, self-renewal, plasticity, and migration. In this review, we elaborate the recent progress in understanding of NTs and their action on various stem cells. First, we provide current knowledge of NTs, proNTs, and their receptor isoforms and signaling pathways. Subsequently, we describe recent advances in the understanding of NT activities in various stem cells and their role in NDs, particularly Alzheimer's disease (AD) and Parkinson's disease (PD). Finally, we compile the implications of NTs and stem cells from a clinical perspective and discuss the challenges with regard to transplantation therapy for treatment of AD and PD.
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Affiliation(s)
- Subrata Pramanik
- Graduate School of Biomedical Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 133-791, Republic of Korea
| | - Yanuar Alan Sulistio
- Graduate School of Biomedical Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 133-791, Republic of Korea
| | - Klaus Heese
- Graduate School of Biomedical Science and Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul, 133-791, Republic of Korea.
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16
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Proenca CC, Song M, Lee FS. Differential effects of BDNF and neurotrophin 4 (NT4) on endocytic sorting of TrkB receptors. J Neurochem 2016; 138:397-406. [PMID: 27216821 DOI: 10.1111/jnc.13676] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 05/03/2016] [Accepted: 05/19/2016] [Indexed: 01/31/2023]
Abstract
Neurotrophins are a family of growth factors playing key roles in the survival, development, and function of neurons. The neurotrophins brain-derived neurotrophic factor (BDNF) and NT4 both bind to and activate TrkB receptors, however, they mediate distinct neuronal functions. The molecular mechanism of how TrkB activation by BDNF and NT4 leads to diverse outcomes is unknown. Here, we report that BDNF and NT4 lead to differential endocytic sorting of TrkB receptors resulting in diverse biological functions in cultured cortical neurons. Fluorescent microscopy and surface biotinylation experiments showed that both neurotrophins stimulate internalization of TrkB with similar kinetics. Exposure to BDNF for 2-3 h reduced the surface pool of TrkB receptors to half, whereas a longer treatment (4-5 h) with NT4 was necessary to achieve a similar level of down-regulation. Although BDNF and NT4 induced TrkB phosphorylation with similar intensities, BDNF induced more rapid ubiquitination and degradation of TrkB than NT4. Interestingly, TrkB receptor ubiquitination by these ligands have substantially different pH sensitivities, resulting in varying degrees of receptor ubiquitination at lower pH levels. Consequently, NT4 was capable of maintaining longer sustained downstream signaling activation that correlated with reduced TrkB ubiquitination at endosomal pH. Thus, by leading to altered endocytic trafficking itineraries for TrkB receptors, BDNF and NT4 elicit differential TrkB signaling in terms of duration, intensity, and specificity, which may contribute to their functional differences in vivo. The neurotrophins, brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT4), both bind to and activate TrkB receptors, however, they mediate distinct neuronal functions. Here, we propose that BDNF and NT4 lead to differential endocytic sorting of TrkB receptors resulting in diverse biological functions. BDNF induces more rapid ubiquitination and degradation of TrkB than NT4. Consequently, NT4 is capable of maintaining more sustained signaling downstream of TrkB receptors.
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Affiliation(s)
- Catia C Proenca
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Minseok Song
- Synaptic Circuit Plasticity Laboratory, Department of Structure & Function of Neural Network, Korea Brain Research Institute, 61 Cheomdan-ro, Dong-gu, Daegu, Korea
| | - Francis S Lee
- Department of Psychiatry, Weill Medical College of Cornell University, New York City, New York, USA.,Department of Pharmacology, Weill Medical College of Cornell University, New York City, New York, USA
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17
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D'Angelo L, Avallone L, Cellerino A, de Girolamo P, Paolucci M, Varricchio E, Lucini C. Neurotrophin-4 in the brain of adult Nothobranchius furzeri. Ann Anat 2016; 207:47-54. [PMID: 26970500 DOI: 10.1016/j.aanat.2016.02.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 01/31/2016] [Accepted: 02/08/2016] [Indexed: 12/27/2022]
Abstract
Neurotrophin-4 (NT-4) is a member of the well-known family of neurotrophins that regulate the development of neuronal networks by participating in neuronal survival and differentiation, the growth of neuronal processes, synaptic development and plasticity, as well as myelination. NT-4 interacts with two distinct receptors: TrkB, high affinity receptor and p75 low-affinity neurotrophin receptor (p75(NTR)). In the present survey, we identified the gene encoding NT-4 in the teleost Nothobranchius furzeri, a model species for aging research. The identified gene shows a similarity of about 72% with medaka, the closest related species. The neuroanatomical localization of NT-4 mRNA is obtained by using an LNA probe. NT-4 mRNA expression is observed in neurons and glial cells of the forebrain and hindbrain, with very low signal found in the midbrain. This survey confirms that NT-4 is expressed in the brain of N. furzeri during adulthood, suggesting that it could also be implicated in the maintenance and regulation of neuronal functions.
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Affiliation(s)
- L D'Angelo
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - L Avallone
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - A Cellerino
- Scuola Normale Superiore di Pisa, Pisa, Italy; Laboratory of Aging, Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - P de Girolamo
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
| | - M Paolucci
- Department of Sciences and Technologies, University of Sannio, Benevento, Italy
| | - E Varricchio
- Department of Sciences and Technologies, University of Sannio, Benevento, Italy
| | - C Lucini
- Department of Veterinary Medicine and Animal Production, University of Naples Federico II, Naples, Italy
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18
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Szu JI, Binder DK. The Role of Astrocytic Aquaporin-4 in Synaptic Plasticity and Learning and Memory. Front Integr Neurosci 2016; 10:8. [PMID: 26941623 PMCID: PMC4764708 DOI: 10.3389/fnint.2016.00008] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 02/05/2016] [Indexed: 01/05/2023] Open
Abstract
Aquaporin-4 (AQP4) is the predominant water channel expressed by astrocytes in the central nervous system (CNS). AQP4 is widely expressed throughout the brain, especially at the blood-brain barrier where AQP4 is highly polarized to astrocytic foot processes in contact with blood vessels. The bidirectional water transport function of AQP4 suggests its role in cerebral water balance in the CNS. The regulation of AQP4 has been extensively investigated in various neuropathological conditions such as cerebral edema, epilepsy, and ischemia, however, the functional role of AQP4 in synaptic plasticity, learning, and memory is only beginning to be elucidated. In this review, we explore the current literature on AQP4 and its influence on long term potentiation (LTP) and long term depression (LTD) in the hippocampus as well as the potential relationship between AQP4 and in learning and memory. We begin by discussing recent in vitro and in vivo studies using AQP4-null and wild-type mice, in particular, the impairment of LTP and LTD observed in the hippocampus. Early evidence using AQP4-null mice have suggested that impaired LTP and LTD is brain-derived neurotrophic factor dependent. Others have indicated a possible link between defective LTP and the downregulation of glutamate transporter-1 which is rescued by chronic treatment of β-lactam antibiotic ceftriaxone. Furthermore, behavioral studies may shed some light into the functional role of AQP4 in learning and memory. AQP4-null mice performances utilizing Morris water maze, object placement tests, and contextual fear conditioning proposed a specific role of AQP4 in memory consolidation. All together, these studies highlight the potential influence AQP4 may have on long term synaptic plasticity and memory.
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Affiliation(s)
| | - Devin K. Binder
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, RiversideCA, USA
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19
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Koudelka J, Horn JM, Vatanashevanopakorn C, Minichiello L. Genetic dissection of TrkB activated signalling pathways required for specific aspects of the taste system. Neural Dev 2014; 9:21. [PMID: 25256039 PMCID: PMC4178162 DOI: 10.1186/1749-8104-9-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 09/18/2014] [Indexed: 01/26/2023] Open
Abstract
Background Neurotrophin-4 (NT-4) and brain derived neurotrophic factor (BDNF) bind to the same receptor, Ntrk2/TrkB, but play distinct roles in the development of the rodent gustatory system. However, the mechanisms underlying these processes are lacking. Results Here, we demonstrate, in vivo, that single or combined point mutations in major adaptor protein docking sites on TrkB receptor affect specific aspects of the mouse gustatory development, known to be dependent on BDNF or NT-4. In particular, mice with a mutation in the TrkB-SHC docking site had reduced gustatory neuron survival at both early and later stages of development, when survival is dependent on NT-4 and BDNF, respectively. In addition, lingual innervation and taste bud morphology, both BDNF-dependent functions, were altered in these mutants. In contrast, mutation of the TrkB-PLCγ docking site alone did not affect gustatory neuron survival. Moreover, innervation to the tongue was delayed in these mutants and taste receptor expression was altered. Conclusions We have genetically dissected pathways activated downstream of the TrkB receptor that are required for specific aspects of the taste system controlled by the two neurotrophins NT-4 and BDNF. In addition, our results indicate that TrkB also regulate the expression of specific taste receptors by distinct signalling pathways. These results advance our knowledge of the biology of the taste system, one of the fundamental sensory systems crucial for an organism to relate to the environment.
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Affiliation(s)
| | | | | | - Liliana Minichiello
- Centre for Neuroregeneration, University of Edinburgh, EH16 4SB Edinburgh, UK.
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20
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Benn K, Passos M, Jayaram A, Harris M, Bongiovanni AM, Skupski D, Witkin SS. Association Between Neurotrophin 4 and Long-Chain Polyunsaturated Fatty Acid Levels in Mid-Trimester Amniotic Fluid. Reprod Sci 2014; 21:1395-400. [DOI: 10.1177/1933719114526474] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Kiesha Benn
- Department of Obstetrics and Gynecology, Division of Immunology and Infectious Diseases, Weill Cornell Medical College, New York, NY, USA
- Department of Obstetrics and Gynecology, New York Hospital Queens, Queens, New York, NY, USA
| | - Mariana Passos
- Department of Obstetrics and Gynecology, Division of Immunology and Infectious Diseases, Weill Cornell Medical College, New York, NY, USA
| | - Aswathi Jayaram
- Department of Obstetrics and Gynecology, Division of Immunology and Infectious Diseases, Weill Cornell Medical College, New York, NY, USA
| | - Mary Harris
- Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO, USA
| | - Ann Marie Bongiovanni
- Department of Obstetrics and Gynecology, Division of Immunology and Infectious Diseases, Weill Cornell Medical College, New York, NY, USA
| | - Daniel Skupski
- Department of Obstetrics and Gynecology, New York Hospital Queens, Queens, New York, NY, USA
| | - Steven S. Witkin
- Department of Obstetrics and Gynecology, Division of Immunology and Infectious Diseases, Weill Cornell Medical College, New York, NY, USA
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Abstract
Complex interactions between the brain and peripheral tissues mediate the effective control of energy balance and body weight. Hypothalamic and hindbrain neural circuits integrate peripheral signals informing the nutritional status of the animal and in response regulate nutrient intake and energy utilization. Obesity and its many medical complications emerge from the dysregulation of energy homeostasis. Excessive weight gain might also arise from alterations in reward systems of the brain that drive consumption of calorie dense, palatable foods in the absence of an energy requirement. Several neurotrophins, most notably brain-derived neurotrophic factor, have been implicated in the molecular and cellular processes underlying body weight regulation. Here, we review investigations interrogating their roles in energy balance and reward centers of the brain impacting feeding behavior and energy expenditure.
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Affiliation(s)
- M Rios
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, 02111, USA,
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22
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BDNF and NT4 play interchangeable roles in gustatory development. Dev Biol 2013; 386:308-20. [PMID: 24378336 DOI: 10.1016/j.ydbio.2013.12.031] [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: 10/02/2013] [Revised: 12/17/2013] [Accepted: 12/20/2013] [Indexed: 01/10/2023]
Abstract
A limited number of growth factors are capable of regulating numerous developmental processes, but how they accomplish this is unclear. The gustatory system is ideal for examining this issue because the neurotrophins brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT4) have different developmental roles although both of them activate the same receptors, TrkB and p75. Here we first investigated whether the different roles of BDNF and NT4 are due to their differences in temporal and spatial expression patterns. Then, we asked whether or not these two neurotrophins exert their unique roles on the gustatory system by regulating different sets of downstream genes. By using Bdnf(Nt4/Nt4) mice, in which the coding region for BDNF is replaced with NT4, we examined whether the different functions of BDNF and NT4 are interchangeable during taste development. Our results demonstrated that NT4 could mediate most of the unique roles of BDNF during taste development. Specifically, caspase-3-mediated cell death, which was increased in the geniculate ganglion in Bdnf(-/-) mice, was rescued in Bdnf(Nt4/Nt4) mice. In BDNF knockout mice, tongue innervation was disrupted, and gustatory axons failed to reach their targets. However, disrupted innervation was rescued and target innervation is normal when NT4 replaced BDNF. Genome wide expression analyses revealed that BDNF and NT4 mutant mice exhibited different gene expression profiles in the gustatory (geniculate) ganglion. Compared to wild type, the expression of differentiation-, apoptosis- and axon guidance-related genes was changed in BDNF mutant mice, which is consistent with their different roles during taste development. However, replacement of BDNF by NT4 rescued these gene expression changes. These findings indicate that the functions of BDNF and NT4 in taste development are interchangeable. Spatial and temporal differences in BDNF and NT4 expression can regulate differential gene expression in vivo and determine their specific roles during development.
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23
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Che H, Song J, Guo S, Wang W, Gao G. Inhibition of xenograft human glioma tumor growth by lentivirus-mediated gene transfer of alphastatin. Oncol Rep 2012; 29:1101-7. [PMID: 23242200 DOI: 10.3892/or.2012.2187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Accepted: 11/09/2012] [Indexed: 11/05/2022] Open
Abstract
Angiogenesis is crucial for the development and metastasis of human brain glioma. Based on our previous successful construction of a lentivirus-mediated alphastatin (an endogenous angiogenesis inhibitor) gene transfer system and our findings that alphastatin exhibited potent inhibitory effects on the migration and differentiation of human umbilical vein endothelial cell lines (HUVECs) induced by vascular endothelial growth factor (VEGF) or basic fibroblast growth factor (bFGF) in vitro, here, we investigated the effect of using lentiviral vectors to overexpress alphastatin in human glioma cells to show whether sustained long-term expression of alphastatin diminishes tumor growth in a xenograft glioma model. We found that the transduced glioma cells sustainedly secreted alphastatin, which did not affect the proliferative ability of the glioma cells. Furthermore, tumor xenografts treated with the recombinant lentivirus were significantly smaller compared to the control xenografts and vascularity within the treated tumors was evidently decreased. Our data suggest that stable expression of alphastatin inhibits human glioma growth by inhibiting angiogenesis, with a probable mechanism of suppressing the turnover of VE-cadherin membrane molecules.
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Affiliation(s)
- Hongmin Che
- Department of Neurosurgery, The Second Affiliated Hospital, the Fourth Military Medical University, Xi'an 710038, PR China
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24
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Runge EM, Hoshino N, Biehl MJ, Ton S, Rochlin MW. Neurotrophin-4 is more potent than brain-derived neurotrophic factor in promoting, attracting and suppressing geniculate ganglion neurite outgrowth. Dev Neurosci 2012; 34:389-401. [PMID: 23151843 DOI: 10.1159/000342996] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 08/23/2012] [Indexed: 12/23/2022] Open
Abstract
The geniculate ganglion, which provides innervation to taste buds in the anterior tongue and palate, is unique among sensory ganglia in that its neurons depend on both neurotrophin-4 (NT4) and brain-derived neurotrophic factor (BDNF) for survival. Whereas BDNF is additionally implicated in taste axon guidance at targeting stages, much less is known about the guidance role of NT4 during targeting, or about either neurotrophin during initial pathfinding. NT4 and BDNF have distinct expression patterns in vivo, raising the possibility of distinct roles. We characterized the influence of NT4 and BDNF on geniculate neurites in collagen I gels at early embryonic through postnatal stages. During early pathfinding to the tongue (embryonic days 12-13; E12-13), NT4 and BDNF promote significantly longer outgrowth than during intralingual targeting (E15-18). NT4 is more potent than BDNF at stimulating neurite outgrowth and both factors exhibit concentration optima, i.e. intermediate concentrations (0.25 ng/ml NT4 or 25 ng/ml BDNF) promote maximal neurite extension and high concentrations (10 ng/ml NT4 or 200 ng/ml BDNF) suppress it. Only partial suppression was seen at E12 (when axons first emerge from the ganglion in vivo) and postnatally, but nearly complete suppression occurred from E13 to E18. We show that cell death is not responsible for suppression. Although blocking the p75 receptor reduces outgrowth at the optimum concentrations of NT4 and BDNF, it did not reduce suppression of outgrowth. We also report that NT4, like BDNF, can act as a chemoattractant for geniculate neurites, and that the tropic influence is strongest during intralingual targeting (E15-18). NT4 does not appear to act as an attractant in vivo, but it may prevent premature invasion of the epithelium by suppressing axon growth.
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Affiliation(s)
- Elizabeth M Runge
- Biology Department, Loyola University Chicago, Chicago, IL 60660, USA
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25
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Guo SW, Che HM, Li WZ. Anti-tumor effect of lentivirus-mediated gene transfer of alphastatin on human glioma. Cancer Sci 2011; 102:1038-44. [PMID: 21255189 DOI: 10.1111/j.1349-7006.2011.01879.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Alphastatin, an endogenous angiogenesis inhibitor, has recently been used as an anticancer agent in several tumor models. This study was to investigate whether local sustained long-term expression of alphastatin could serve to diminish tumor growth of a human xenograft glioma model. We found that the recombinant alphastatin lentiviruses were able to stably infect HUVECs, and infected HUVECs could sustainably secrete alphastatin, which exhibited potent inhibitory effects on HUVECs migration, differentiation but not proliferation induced by vascular endothelial growth factor (VEGF) or basic fibroblast growth factor(bFGF). And the expression of secreted protein alphastatin markedly decreased tumor vascularization and inhibited tumor growth. Additionally, alphastatin inhibited VEGF- or bFGF-induced initial stage of angiogenesis by reducing JNk and ERK phosphorylation in vitro. Taken together, these data demonstrate that secreted protein alphastatin inhibits VEGF- or bFGF-induced angiogenesis by suppressing JNK and ERK kinases activation pathways in HUVECs, and markedly inhibits tumor angiogenesis in vivo. Consequently lentivirus-mediated gene transfer might represent an effective strategy for expression of alphastatin to achieve inhibition of human malignant glioma proliferation and tumor progression.
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Affiliation(s)
- Shi-Wen Guo
- Department of Neurosurgery, First Affiliated Hospital, Medical School of Xi'an Jiaotong University, Xi'an, China.
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Zeng Y, Zhao D, Xie CW. Neurotrophins enhance CaMKII activity and rescue amyloid-β-induced deficits in hippocampal synaptic plasticity. J Alzheimers Dis 2011; 21:823-31. [PMID: 20634586 DOI: 10.3233/jad-2010-100264] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Amyloid-β (Aβ) peptide-induced impairment of hippocampal synaptic plasticity is considered an underlying mechanism for memory loss in the early stages of Alzheimer's disease and its animal models. We previously reported inhibition of long-term potentiation (LTP) and miniature excitatory postsynaptic currents by oligomeric Aβ(1-42) at hippocampal synapses. While multiple cellular mechanisms could be involved in Aβ-induced synaptic dysfunction, blockade of activity-dependent autophosphorylation of Ca2+ and calmodulin-dependent protein kinase II (CaMKII) appeared to be a major component of Aβ action in our studies. The present study further tested this hypothesis and examined the therapeutic potential of trkB receptor-acting neurotrophins in rescuing Aβ-induced synaptic and signaling impairments. As expected, treatment of rat hippocampal slices with Aβ(1-42) significantly reduced LTP in the Schaffer collateral-CA1 pathway and dentate medial perforant path. LTP-associated CaMKII activation and AMPA receptor phosphorylation were blocked by Aβ(1-42) at the same concentration that inhibited LTP. Aβ-induced LTP impairment, however, was prevented when slices were co-treated with neurotrophin 4 (NT4). Western blotting and immunohistochemical analyses confirmed that treatment with NT4 or brain-derived neurotrophic factor, another trkB-acting neurotrophin, could oppose Aβ action, enhancing autophosphorylation of CaMKII, and AMPA receptor phosphorylation at a CaMKII-dependent site. These findings support the view that CaMKII is a key synaptic target of Aβ toxicity as well as a potential therapeutic site of neurotrophins for Alzheimer's disease.
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Affiliation(s)
- Yan Zeng
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA 90024, USA
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Patel AV, Huang T, Krimm RF. Lingual and palatal gustatory afferents each depend on both BDNF and NT-4, but the dependence is greater for lingual than palatal afferents. J Comp Neurol 2010; 518:3290-301. [PMID: 20575060 DOI: 10.1002/cne.22400] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Neurons of the geniculate ganglion innervate taste buds located in two spatially distinct targets, the tongue and palate. About 50% of these neurons die in Bdnf(-/-) mice and Ntf4/5(-/-) mice. Bdnf(-/-)/Ntf4/5(-/-) double mutants lose 90-95% of geniculate ganglion neurons. To determine whether different subpopulations are differentially influenced by neurotrophins, we quantified neurons from two ganglion subpopulations separately and remaining taste buds at birth within each target field in wild-type, Bdnf(-/-), Ntf4/5(-/-), and Bdnf(-/-)/Ntf4/5(-/-) mice. In wild-type mice the same number of neurons innervated the anterior tongue and soft palate and each target contained the same number of taste buds. Compared to wild-type mice, Bdnf(-/-) mice showed a 50% reduction in geniculate neurons innervating the tongue and a 28% loss in neurons innervating the soft palate. Ntf4/5(-/-) mice lost 58% of the neurons innervating the tongue and 41% of the neurons innervating the soft palate. Taste bud loss was not as profound in the NT-4 null mice compared to BDNF-null mice. Tongues of Bdnf(-/-)/Ntf4/5(-/-) mice were innervated by 0 to 4 gustatory neurons and contained 3 to 16 taste buds at birth, indicating that some taste buds remain even when all innervation is lost. Thus, gustatory neurons are equally dependent on BDNF and NT-4 expression for survival, regardless of what peripheral target they innervate. However, taste buds are more sensitive to BDNF than NT-4 removal.
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Affiliation(s)
- Ami V Patel
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky 40292, USA
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Childs AJ, Bayne RAL, Murray AA, Martins Da Silva SJ, Collins CS, Spears N, Anderson RA. Differential expression and regulation by activin of the neurotrophins BDNF and NT4 during human and mouse ovarian development. Dev Dyn 2010; 239:1211-9. [PMID: 20175187 PMCID: PMC3410523 DOI: 10.1002/dvdy.22252] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The tropomyosin-related kinase (Trk) B neurotrophin receptor is essential for ovarian germ cell survival and primordial follicle formation, but the contributions of its ligands, brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT4), are unknown. We have investigated their expression and regulation in developing human and mouse ovaries. BDNF expression increased with increasing gestation, expression of human NTF4 and of both Ntf5 and Bdnf in the mouse was unchanged. Bdnf expression was dramatically lower than Ntf5 in the mouse, but levels were comparable in the human. Human fetal ovarian somatic cells expressed BDNF. Activin A selectively regulated BDNF and Ntf5 expression in human and mouse, respectively, identifying an oocyte/somatic signaling pathway which might mediate the pro-survival effects of activin. These data reveal that expression and regulation of the TrkB ligands are differentially controlled in the developing ovaries of humans and mice, and identify BDNF as a potential regulator of germ cell fate in the human fetal ovary.
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Affiliation(s)
- Andrew J Childs
- MRC Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, Edinburgh EH16 4TJ, United Kingdom.
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Montaño JA, Pérez-Piñera P, García-Suárez O, Cobo J, Vega JA. Development and neuronal dependence of cutaneous sensory nerve formations: Lessons from neurotrophins. Microsc Res Tech 2010; 73:513-29. [PMID: 19839059 DOI: 10.1002/jemt.20790] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Null mutations of genes from the NGF family of NTs and their receptors (NTRs) lead to loss/reduction of specific neurons in sensory ganglia; conversely, cutaneous overexpression of NTs results in skin hyperinnervation and increase or no changes in the number of sensory neurons innervating the skin. These neuronal changes are paralleled with loss of specific types of sensory nerve formations in the skin. Therefore, mice carrying mutations in NT or NTR genes represent an ideal model to identify the neuronal dependence of each type of cutaneous sensory nerve ending from a concrete subtype of sensory neuron, since the development, maintenance, and structural integrity of sensory nerve formations depend upon sensory neurons. Results obtained from these mouse strains suggest that TrkA positive neurons are connected to intraepithelial nerve fibers and other sensory nerve formations depending from C and Adelta nerve fibers; the neurons expressing TrkB and responding to BDNF and NT-4 innervate Meissner corpuscles, a subpopulation of Merkell cells, some mechanoreceptors of the piloneural complex, and the Ruffini's corpuscles; finally, a subpopulation of neurons, which are responsive to NT-3, support postnatal survival of some intraepithelial nerve fibers and Merkel cells in addition to the muscle mechanoreceptors. On the other hand, changes in NTs and NTRs affect the structure of non-nervous structures of the skin and are at the basis of several cutaneous pathologies. This review is an update about the role of NTs and NTRs in the maintenance of normal cutaneous innervation and maintenance of skin integrity.
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Affiliation(s)
- Juan A Montaño
- Departamento de Ciencias de la Salud, Universidad Católica San Antonio, Murcia, Spain
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Massa SM, Yang T, Xie Y, Shi J, Bilgen M, Joyce JN, Nehama D, Rajadas J, Longo FM. Small molecule BDNF mimetics activate TrkB signaling and prevent neuronal degeneration in rodents. J Clin Invest 2010; 120:1774-85. [PMID: 20407211 DOI: 10.1172/jci41356] [Citation(s) in RCA: 300] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Accepted: 02/17/2010] [Indexed: 02/01/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) activates the receptor tropomyosin-related kinase B (TrkB) with high potency and specificity, promoting neuronal survival, differentiation, and synaptic function. Correlations between altered BDNF expression and/or function and mechanism(s) underlying numerous neurodegenerative conditions, including Alzheimer disease and traumatic brain injury, suggest that TrkB agonists might have therapeutic potential. Using in silico screening with a BDNF loop-domain pharmacophore, followed by low-throughput in vitro screening in mouse fetal hippocampal neurons, we have efficiently identified small molecules with nanomolar neurotrophic activity specific to TrkB versus other Trk family members. Neurotrophic activity was dependent on TrkB and its downstream targets, although compound-induced signaling activation kinetics differed from those triggered by BDNF. A selected prototype compound demonstrated binding specificity to the extracellular domain of TrkB. In in vitro models of neurodegenerative disease, it prevented neuronal degeneration with efficacy equal to that of BDNF, and when administered in vivo, it caused hippocampal and striatal TrkB activation in mice and improved motor learning after traumatic brain injury in rats. These studies demonstrate the utility of loop modeling in drug discovery and reveal what we believe to be the first reported small molecules derived from a targeted BDNF domain that specifically activate TrkB.We propose that these compounds constitute a novel group of tools for the study of TrkB signaling and may provide leads for developing new therapeutic agents for neurodegenerative diseases.
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Affiliation(s)
- Stephen M Massa
- Department of Neurology and Laboratory for Computational Neurochemistry and Drug Discovery, UCSF, San Francisco, California, USA
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Song LP, Li YP, Wang N, Li WW, Ren J, Qiu SD, Wang QY, Yang GX. NT4(Si)-p53(N15)-antennapedia induces cell death in a human hepatocellular carcinoma cell line. World J Gastroenterol 2009; 15:5813-20. [PMID: 19998502 PMCID: PMC2791274 DOI: 10.3748/wjg.15.5813] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To construct the recombinant lentivirus expression plasmid, pLenti6/V5-NT4 p53(N15)-antennapedia (Ant), and study its effect on HepG2 cells.
METHODS: Plasmid pLenti6/V5-NT4 p53(N15)-Ant was constructed incorporating the following functional regions, including signal peptide sequence and pro-region of neurotrophin 4, N-terminal residues 12-26 of p53 and 17 amino acid drosophila carrier protein, Ant. Hepatocellular carcinoma (HepG2) cells were used for transfection. 3-[4,5-dimethyl-thiazol-2yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, lactate dehydrogenase (LDH) release assay, transmission electron microscopy (TEM) and flow cytometric analysis (FCM) were employed to investigate the effects of LV-NT4(Si)-p53(N15)-Ant in vitro on HepG2 cells. In vivo experiment was also performed to investigate the inhibitory effect of LV-NT4(Si)-p53(N15)-Ant on tumor growth in nude mice.
RESULTS: LV-NT4(Si)-p53(N15)-Ant significantly suppressed the growth of HepG2 cells. MTT assay showed that the growth of HepG2 cells was mucj more significantly inhibited by LV-NT4(Si)-p53(N15)-Ant than by LV-EGFP. The inhibition rate for HepG2 cell growth in the two groups was 46.9% and 94.5%, respectively, 48 h after infection with LV-NT4(Si)-p53(N15)-Ant, and was 33.9% and 95.8%, respectively, 72 h after infection with LV-NT4(Si)-p53(N15)-Ant (P < 0.01). Light microscopy and TEM showed morphological changes in HepG2 cells infected with LV-NT4(Si)-p53(N15)-Ant, but no significant changes in HepG2 cells infected with LV-EGFP. Changes were observed in ultra-structure of HepG2 cells infected with LV-NT4(Si)-p53(N15)-Ant, with degraded membranes, resulting in necrosis. LDH release from HepG2 cells was analyzed at 24, 48, 72 and 96 h after infection with LV-NT4(Si)-p53(N15)-Ant and LV-EGFP, which showed that LDH release was significantly higher in LV-NT4(Si)-p53(N15)-Ant treatment group (682 IU/L) than in control group (45 IU/L, P < 0.01). The longer the time was after infection, the bigger the difference was in LDH release. FCM analysis showed that LV-NT4(Si)-p53(N15)-Ant could induce two different kinds of cell death: necrosis and apoptosis, with apoptosis being the minor type and necrosis being the main type, suggesting that LV-NT4(Si)-p53(N15)-Ant exerts its anticancer effect on HepG2 cells by inducing necrosis. The in vivo study showed that LV-NT4(Si)-p53(N15)-Ant significantly inhibited tumor growth with an inhibition rate of 66.14% in terms of tumor size and weight.
CONCLUSION: LV-NT4(Si)-p53(N15)-Ant is a novel recombinant lentivirus expression plasmid and can be used in gene therapy for cancer.
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BDNF signaling in the formation, maturation and plasticity of glutamatergic and GABAergic synapses. Exp Brain Res 2009; 199:203-34. [PMID: 19777221 DOI: 10.1007/s00221-009-1994-z] [Citation(s) in RCA: 221] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Accepted: 08/12/2009] [Indexed: 01/17/2023]
Abstract
In the past 15 years numerous reports provided strong evidence that brain-derived neurotrophic factor (BDNF) is one of the most important modulators of glutamatergic and GABAergic synapses. Remarkable progress regarding localization, kinetics, and molecular mechanisms of BDNF secretion has been achieved, and a large number of studies provided evidence that continuous extracellular supply of BDNF is important for the proper formation and functional maturation of glutamatergic and GABAergic synapses. BDNF can play a permissive role in shaping synaptic networks, making them more susceptible for the occurrence of plastic changes. In addition, BDNF appears to be also an instructive factor for activity-dependent long-term synaptic plasticity. BDNF release just in response to synaptic stimulation might be a molecular trigger to convert high-frequency synaptic activity into long-term synaptic memories. This review attempts to summarize the current knowledge in synaptic secretion and synaptic action of BDNF, including both permissive and instructive effects of BDNF in synaptic plasticity.
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Epithelial-derived brain-derived neurotrophic factor is required for gustatory neuron targeting during a critical developmental period. J Neurosci 2009; 29:3354-64. [PMID: 19295142 DOI: 10.1523/jneurosci.3970-08.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is expressed in epithelial targets of gustatory neurons (i.e., fungiform papillae) before their innervation, and BDNF overexpression in nontaste regions of the tongue misdirects gustatory axons to these sites, suggesting that BDNF is necessary for gustatory axons to locate and innervate their correct targets during development. To test this hypothesis, we examined the targeting of taste neurons in BDNF-null mice (bdnf(-/-)). Analysis of bdnf(-/-) mice using a combination of DiI labeling and electron microscopy revealed that taste regions were not innervated by gustatory axons. Instead, branching was increased and many nontaste regions were innervated. The increased branching by gustatory axons in these animals was facilitated by neurotrophin 4 (NT4), because branching was virtually eliminated in bdnf(-/-)/nt4(-/-) mice. No abnormalities in gustatory innervation patterns and targeting were observed in nt4(-/-) mice. Conditional removal of BDNF selectively in epithelial cells disrupted targeting at the tongue tip, where gene recombination removed bdnf by embryonic day 13.5 (E13.5). However, innervation patterns were normal in the midregion and caudal portions of the tongue, where gene recombination did not occur until E14.5. These findings demonstrate that BDNF derived from gustatory epithelia is required for gustatory axons to correctly locate and innervate fungiform papillae. In addition, they show that BDNF-mediated targeting is restricted to a critical period of development, on or before E13.5.
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Tsao D, Thomsen HK, Chou J, Stratton J, Hagen M, Loo C, Garcia C, Sloane DL, Rosenthal A, Lin JC. TrkB agonists ameliorate obesity and associated metabolic conditions in mice. Endocrinology 2008; 149:1038-48. [PMID: 18063676 DOI: 10.1210/en.2007-1166] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mutations in the tyrosine kinase receptor trkB or in one of its natural ligands, brain-derived neurotrophic factor (BDNF), lead to severe hyperphagia and obesity in rodents and/or humans. Here, we show that peripheral administration of neurotrophin-4 (NT4), the second natural ligand for trkB, suppresses appetite and body weight in a dose-dependent manner in several murine models of obesity. NT4 treatment increased lipolysis, reduced body fat content and leptin, and elicited long-lasting amelioration of hypertriglyceridemia and hyperglycemia. After treatment termination, body weight gradually recovered to control levels in obese mice with functional leptin receptor. A single intrahypothalamic application of minute amounts of NT4 or an agonist trkB antibody also reduced food intake and body weight in mice. Taken together with the genetic evidence, our findings support the concept that trkB signaling, which originates in the hypothalamus, directly modulates appetite, metabolism, and taste preference downstream of the leptin and melanocortin 4 receptor. The trkB agonists mediate anorexic and weight-reducing effects independent of stress induction, visceral discomfort, or pain sensitization and thus emerge as a potential therapeutic for metabolic disorders.
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Affiliation(s)
- David Tsao
- Rinat Laboratories, Pfizer Inc., 230 East Grand Avenue, South San Francisco, California 94080, USA
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Abstract
The ability of the skin to serve as a protective shield against environmental challenges and as a sensitive detector and responder to thermal, chemical, and mechanical stimuli speaks to its exquisite design. A central feature of this design is the diverse array of neuronal afferents that convey and respond to sensory stimuli that the skin encounters. Cutaneous neuron development, form, and function are highly dependent on communication with the skin through its production of multiple growth factor proteins that modulate afferent development, maturation, and function. Production by the skin of neurotrophin growth factors and members of the glial cell line-derived neurotrophic factor family are particularly important for support of specific subsets of sensory neurons with unique phenotypic and functional properties. Although these proteins have central roles in afferent development and function, challenges remain in identifying specific molecular mechanisms of growth factor communication and understanding how activation of signaling pathways direct neuron differentiation and function under normal and pathological conditions.
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Affiliation(s)
- Kathryn M Albers
- Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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Royo NC, LeBold D, Magge SN, Chen I, Hauspurg A, Cohen AS, Watson DJ. Neurotrophin-mediated neuroprotection of hippocampal neurons following traumatic brain injury is not associated with acute recovery of hippocampal function. Neuroscience 2007; 148:359-70. [PMID: 17681695 PMCID: PMC2579330 DOI: 10.1016/j.neuroscience.2007.06.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Revised: 06/12/2007] [Accepted: 06/18/2007] [Indexed: 11/23/2022]
Abstract
Traumatic brain injury (TBI) causes selective hippocampal cell death which is believed to be associated with the cognitive impairment observed in both clinical and experimental settings. The endogenous neurotrophin-4/5 (NT-4/5), a TrkB ligand, has been shown to be neuroprotective for vulnerable CA3 pyramidal neurons after experimental brain injury. In this study, infusion of recombinant NT-4/5 increased survival of CA2/3 pyramidal neurons to 71% after lateral fluid percussion brain injury in rats, compared with 55% in vehicle-treated controls. The functional outcome of this NT-4/5-mediated neuroprotection was examined using three hippocampal-dependent behavioral tests. Injury-induced impairment was evident in all three tests, but interestingly, there was no treatment-related improvement in any of these measures. Similarly, injury-induced decreased excitability in the Schaffer collaterals was not affected by NT-4/5 treatment. We propose that a deeper understanding of the factors that link neuronal survival to recovery of function will be important for future studies of potentially therapeutic agents.
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Affiliation(s)
- N C Royo
- Department of Neurosurgery, 371A Stemmler Hall/6071, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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Calamusa M, Pattabiraman PP, Pozdeyev N, Iuvone PM, Cellerino A, Domenici L. Specific alterations of tyrosine hydroxylase immunopositive cells in the retina of NT-4 knock out mice. Vision Res 2007; 47:1523-36. [PMID: 17350071 DOI: 10.1016/j.visres.2007.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Revised: 01/26/2007] [Accepted: 01/26/2007] [Indexed: 11/23/2022]
Abstract
To assess the effect of NT-4 deprivation on maturation of retinal circuitry, we investigated a mouse with targeted deletion of the gene encoding nt-4 (nt-4(-/-)). In particular, we studied neurons immunostained by an antibody recognizing tyrosine hydroxylase (TH), the rate limiting enzyme for dopamine (DA) synthesis. We found that TH immunopositive processes were altered in the retina of nt-4(-/-). Alteration of TH immunopositive processes in nt-4(-/-) mice resulted in changes of DA turnover, as assessed by high-pressure liquid chromatography measurements. These findings suggest that retinal NT-4 plays a role in the morphological maturation of dopaminergic retinal cells.
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Affiliation(s)
- Martina Calamusa
- Istituto di Neuroscienze, Consiglio Nazionale delle Ricerche (CNR), Via G. Moruzzi 1, 56100 Pisa, Italy
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Roux S, Saint Cloment C, Curie T, Girard E, Miana Mena FJ, Barbier J, Osta R, Molgó J, Brûlet P. Brain-derived neurotrophic factor facilitates in vivo internalization of tetanus neurotoxin C-terminal fragment fusion proteins in mature mouse motor nerve terminals. Eur J Neurosci 2007; 24:1546-54. [PMID: 17004918 DOI: 10.1111/j.1460-9568.2006.05030.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In a previous study it was reported that fusion proteins composed of the atoxic C-terminal fragment of tetanus toxin (TTC) and green fluorescent protein or beta-galactosidase (GFP-TTC and beta-gal-TTC, respectively) rapidly cluster at motor nerve terminals of the mouse neuromuscular junction (NMJ). Because this traffic involves presynaptic activity, probably via the secretion of active molecules, we examined whether it is affected by brain-derived neurotrophic factor (BDNF). Quantitative confocal microscopy and a fluorimetric assay for beta-gal activity revealed that co-injecting BDNF and the fusion proteins significantly increased the kinetics and amount of the proteins' localization at the NMJ and their internalization by motor nerve terminals. The observed increases were independent of synaptic vesicle recycling because BDNF did not affect spontaneous quantal acetylcholine release. In addition, injecting anti-BDNF antibody shortly before injecting GFP-TTC, and before co-injecting GFP-TTC and BDNF, significantly reduced the fusion protein's localization at the NMJ. Co-injecting GFP-TTC with neurotrophin-4 (NT-4) or glial-derived neurotrophic factor (GDNF), but not with nerve growth factor, neurotrophin-3 or ciliary neurotrophic factor, also significantly increased the fusion protein's localization at the NMJ. Thus, TTC probes may use for their neuronal internalization endocytic pathways normally stimulated by BDNF, NT-4 and GDNF binding. Different tyrosine kinase receptors with similar signalling pathways are activated by BDNF/NT-4 and GDNF binding. Thus, activated components of these signalling pathways may be involved in the TTC probes' internalization, perhaps by facilitating localization of receptors of TTC in specific membrane microdomains or by recruiting various factors needed for internalization of TTC.
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Affiliation(s)
- Sylvie Roux
- CNRS, Institut de Neurobiologie Alfred Fessard, FRC2118, Laboratoire de Neurobiologie Cellulaire et Moléculaire, UPR9040, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France
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Egles C, Claudepierre T, Manglapus MK, Champliaud MF, Brunken WJ, Hunter DD. Laminins containing the beta2 chain modulate the precise organization of CNS synapses. Mol Cell Neurosci 2006; 34:288-98. [PMID: 17189701 DOI: 10.1016/j.mcn.2006.11.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Revised: 10/26/2006] [Accepted: 11/10/2006] [Indexed: 11/30/2022] Open
Abstract
Synapses are formed and stabilized by concerted interactions of pre-, intra-, and post-synaptic components; however, the precise nature of the intrasynaptic components in the CNS remains obscure. Potential intrasynaptic components include extracellular matrix molecules such as laminins; here, we isolate beta2-containing laminins, including perhaps laminins 13 (alpha3beta2gamma3) and 14 (alpha4beta2gamma3), from CNS synaptosomes suggesting a role for these molecules in synaptic organization. Indeed, hippocampal synapses that form in vivo in the absence of these laminins are malformed at the ultrastructural level and this malformation is replicated in synapses formed in vitro, where laminins are provided largely by the post-synaptic neuron. This recapitulation of the in vivo function of laminins in vitro suggests that the malformations are a direct consequence of the removal of laminins from the synapse. Together, these results support a role for neuronal laminins in the structural integrity of central synapses.
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Affiliation(s)
- Christophe Egles
- Department of Neuroscience, Tufts Center for Vision Research, Boston, MA 02111, USA
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Do T, Kerr B, Kuzhikandathil EV. Brain-derived neurotrophic factor regulates the expression of D1 dopamine receptors. J Neurochem 2006; 100:416-28. [PMID: 17116228 DOI: 10.1111/j.1471-4159.2006.04249.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have previously demonstrated that the CAD catecholaminergic neuronal cell line is an appropriate model system to study the regulation of D(1) dopamine receptor expression. In this report, we show that brain-derived neurotrophic factor (BDNF) up-regulates the expression of D(1) dopamine receptor in CAD cells. In addition, by comparing D(1) receptor mRNA expression in wild-type, heterozygous and homozygous trkB knockout mice, we show that TrkB receptor signaling up-regulates D(1) receptor expression in vivo. In CAD cells expressing the TrkB receptor, BDNF increased D(1) receptor mRNA in a time- and dose-dependent manner with a fourfold increase in D(1) receptor mRNA observed as early as 3 h with 10 ng/mL of BDNF. Using different classes and concentrations of kinase inhibitors, we determined that BDNF-induced increase of D(1) receptor mRNA is mediated by the phosphatidylinositol 3-kinase signaling pathway. The increase required both new transcription and protein synthesis, as it was blocked by actinomycin D and cyclohexamide, respectively. Promoter deletion analysis identified a D(1) promoter region necessary for mediating the effect of BDNF. These results provide novel evidence that D(1) dopamine receptor expression is regulated by BDNF and its signaling pathway.
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Affiliation(s)
- Thuy Do
- Department of Pharmacology and Physiology, UMDNJ-New Jersey Medical School, Newark, New Jersey 07103, USA
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Rossi C, Angelucci A, Costantin L, Braschi C, Mazzantini M, Babbini F, Fabbri ME, Tessarollo L, Maffei L, Berardi N, Caleo M. Brain-derived neurotrophic factor (BDNF) is required for the enhancement of hippocampal neurogenesis following environmental enrichment. Eur J Neurosci 2006; 24:1850-6. [PMID: 17040481 DOI: 10.1111/j.1460-9568.2006.05059.x] [Citation(s) in RCA: 449] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Neurogenesis continues to occur in the adult mammalian hippocampus and is regulated by both genetic and environmental factors. It is known that exposure to an enriched environment enhances the number of newly generated neurons in the dentate gyrus. However, the mechanisms by which enriched housing produces these effects are poorly understood. To test a role for neurotrophins, we used heterozygous knockout mice for brain-derived neurotrophic factor (BDNF+/-) and mice lacking neurotrophin-4 (NT-4-/-) together with their wild-type littermates. Mice were either reared in standard laboratory conditions or placed in an enriched environment for 8 weeks. Animals received injections of the mitotic marker bromodeoxyuridine (BrdU) to label newborn cells. Enriched wild-type and enriched NT-4-/- mice showed a two-fold increase in hippocampal neurogenesis as assessed by stereological counting of BrdU-positive cells in the dentate gyrus and double labelling for BrdU and the neuronal marker NeuN. Remarkably, this enhancement of hippocampal neurogenesis was not seen in enriched BDNF+/- mice. Failure to up-regulate BDNF accompanied the lack of a neurogenic response in enriched BDNF heterozygous mice. We conclude that BDNF but not NT-4 is required for the environmental induction of neurogenesis.
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Affiliation(s)
- Chiara Rossi
- Istituto di Neuroscienze C.N.R., via G. Moruzzi 1, 56100 Pisa, Italy
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Krimm RF, Davis BM, Noel T, Albers KM. Overexpression of neurotrophin 4 in skin enhances myelinated sensory endings but does not influence sensory neuron number. J Comp Neurol 2006; 498:455-65. [PMID: 16937395 PMCID: PMC2617788 DOI: 10.1002/cne.21074] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The growth factors neurotrophin 4 (NT4) and brain-derived neurotrophic factor (BDNF) are expressed in the developing skin, activate the trkB tyrosine kinase receptor, and influence the development and survival of specific types of sensory afferents. Whether each factor is capable of regulating the same or overlapping populations of cutaneous afferents during development is unknown. A previous study of mice overexpressing BDNF in the developing skin (BDNF-OE mice) revealed that these animals exhibited increased hair follicle innervation, Meissner corpuscle size, and Merkel cell number in glabrous skin, although no change in the total number of sensory neurons was observed. To determine if NT4 affects cutaneous innervation in a manner similar to BDNF, transgenic mice overexpressing NT4 in skin, under the control of the keratin 14 gene promoter, were examined. Similar to BDNF-OE mice, NT4-OE mice had increased innervation to the skin but no increase in sensory neuron number in either the dorsal root ganglion or trigeminal ganglion. NT4 overexpression also enhanced hair follicle innervation and the size and density of innervation to Meissner corpuscles. Unlike BDNF overexpression, NT4 overexpression did not alter the number of Merkel cells in the glabrous skin, but it did enhance the number of myelinated axons in nerves projecting to skin. Thus, the same pattern of BDNF and NT4 overexpression within the skin produces phenotypes that are both similar and distinctive.
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Affiliation(s)
- Robin F Krimm
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky 40292, USA.
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43
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Roosterman D, Goerge T, Schneider SW, Bunnett NW, Steinhoff M. Neuronal Control of Skin Function: The Skin as a Neuroimmunoendocrine Organ. Physiol Rev 2006; 86:1309-79. [PMID: 17015491 DOI: 10.1152/physrev.00026.2005] [Citation(s) in RCA: 399] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
This review focuses on the role of the peripheral nervous system in cutaneous biology and disease. During the last few years, a modern concept of an interactive network between cutaneous nerves, the neuroendocrine axis, and the immune system has been established. We learned that neurocutaneous interactions influence a variety of physiological and pathophysiological functions, including cell growth, immunity, inflammation, pruritus, and wound healing. This interaction is mediated by primary afferent as well as autonomic nerves, which release neuromediators and activate specific receptors on many target cells in the skin. A dense network of sensory nerves releases neuropeptides, thereby modulating inflammation, cell growth, and the immune responses in the skin. Neurotrophic factors, in addition to regulating nerve growth, participate in many properties of skin function. The skin expresses a variety of neurohormone receptors coupled to heterotrimeric G proteins that are tightly involved in skin homeostasis and inflammation. This neurohormone-receptor interaction is modulated by endopeptidases, which are able to terminate neuropeptide-induced inflammatory or immune responses. Neuronal proteinase-activated receptors or transient receptor potential ion channels are recently described receptors that may have been important in regulating neurogenic inflammation, pain, and pruritus. Together, a close multidirectional interaction between neuromediators, high-affinity receptors, and regulatory proteases is critically involved to maintain tissue integrity and regulate inflammatory responses in the skin. A deeper understanding of cutaneous neuroimmunoendocrinology may help to develop new strategies for the treatment of several skin diseases.
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44
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Royo NC, Conte V, Saatman KE, Shimizu S, Belfield CM, Soltesz KM, Davis JE, Fujimoto ST, McIntosh TK. Hippocampal vulnerability following traumatic brain injury: a potential role for neurotrophin-4/5 in pyramidal cell neuroprotection. Eur J Neurosci 2006; 23:1089-102. [PMID: 16553773 DOI: 10.1111/j.1460-9568.2006.04642.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Traumatic brain injury (TBI) causes selective hippocampal cell death, which is believed to be associated with cognitive impairment observed both in clinical and experimental settings. Although neurotrophin administration has been tested as a strategy to prevent cell death following TBI, the potential neuroprotective role of neurotrophin-4/5 (NT-4/5) in TBI remains unknown. We hypothesized that NT-4/5 would offer neuroprotection for selectively vulnerable hippocampal neurons following TBI. Measurements of NT-4/5 in rats subjected to lateral fluid percussion (LFP) TBI revealed two-threefold increases in the injured cortex and hippocampus in the acute period (1-3 days) following brain injury. Subsequently, the response of NT-4/5 knockout (NT-4/5(-/-)) mice to controlled-cortical impact TBI was investigated. NT-4/5(-/-) mice were more susceptible to selective pyramidal cell loss in Ahmon's corn (CA) subfields of the hippocampus following TBI, and showed impaired motor recovery when compared with their brain-injured wild-type controls (NT-4/5(wt)). Additionally, we show that acute, prolonged administration of recombinant NT-4/5 (5 microg/kg/day) prevented up to 50% of the hippocampal CA pyramidal cell death following LFP TBI in rats. These results suggest that post-traumatic increases in endogenous NT-4/5 may be part of an adaptive neuroprotective response in the injured brain, and that administration of this neurotrophic factor may be useful as a therapeutic strategy following TBI.
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Affiliation(s)
- N C Royo
- Laboratory for Traumatic Brain Injury, Department of Neurosurgery, University of Pennsylvania, Philadelphia, USA.
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45
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Pitts EV, Potluri S, Hess DM, Balice-Gordon RJ. Neurotrophin and Trk-mediated signaling in the neuromuscular system. Int Anesthesiol Clin 2006; 44:21-76. [PMID: 16849956 DOI: 10.1097/00004311-200604420-00004] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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46
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Fox EA. A genetic approach for investigating vagal sensory roles in regulation of gastrointestinal function and food intake. Auton Neurosci 2006; 126-127:9-29. [PMID: 16677865 DOI: 10.1016/j.autneu.2006.03.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Revised: 02/28/2006] [Accepted: 03/07/2006] [Indexed: 12/26/2022]
Abstract
Sensory innervation of the gastrointestinal (GI) tract by the vagus nerve plays important roles in regulation of GI function and feeding behavior. This innervation is composed of a large number of sensory pathways, each arising from a different population of sensory receptors. Progress in understanding the functions of these pathways has been impeded by their close association with vagal efferent, sympathetic, and enteric systems, which makes it difficult to selectively label or manipulate them. We suggest that a genetic approach may overcome these barriers. To illustrate the potential value of this strategy, as well as to gain insights into its application, investigations of CNS pathways and peripheral tissues involved in energy balance that benefited from the use of gene manipulations are reviewed. Next, our studies examining the feasibility of using mutations of developmental genes for manipulating individual vagal afferent pathways are reviewed. These experiments characterized mechanoreceptor morphology, density and distribution, and feeding patterns in four viable mutant mouse strains. In each strain a single population of vagal mechanoreceptors innervating the muscle wall of the GI tract was altered, and was associated with selective effects on feeding patterns, thus supporting the feasibility of this strategy. However, two limitations of this approach must be addressed for it to achieve its full potential. First, mutation effects in tissues outside the GI tract can contribute to changes in GI function or feeding. Additionally, knockouts of developmental genes are often lethal, preventing analysis of mature innervation and ingestive behavior. To address these issues, we propose to develop conditional gene knockouts restricted to specific GI tract tissues. Two genes of interest are brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3), which are essential for vagal afferent development. Creating conditional knockouts of these genes requires knowledge of their GI tract expression during development, which little is known about. Preliminary investigation revealed that during development BDNF and NT-3 are each expressed in several GI tract regions, and that their expression patterns overlap in some tissues, but are distinct in others. Importantly, GI tissues that express BDNF or NT-3 are innervated by vagal afferents, and expression of these neurotrophins occurs during the periods of axon invasion and receptor formation, consistent with roles for BDNF or NT-3 in these processes and in receptor survival. These results provide a basis for targeting BDNF or NT-3 knockouts to specific GI tract tissues, and potentially altering vagal afferent innervation only in that tissue (e.g., smooth muscle vs. mucosa). Conditional BDNF or NT-3 knockouts that are successful in selectively altering a vagal GI afferent pathway will be valuable for developing an understanding of that pathway's roles in GI function and food intake.
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Affiliation(s)
- Edward Alan Fox
- Purdue University, Department of Psychological Sciences, 703 Third Street, West Lafayette, Indiana 47907, USA.
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Prakash YS, Iyanoye A, Ay B, Mantilla CB, Pabelick CM. Neurotrophin effects on intracellular Ca2+ and force in airway smooth muscle. Am J Physiol Lung Cell Mol Physiol 2006; 291:L447-56. [PMID: 16648236 DOI: 10.1152/ajplung.00501.2005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurotrophins [e.g., brain-derived neurotrophic factor (BDNF), neurotrophin 4 (NT4)], known to affect neuronal structure and function, are expressed in nonneuronal tissues including the airway. However, their function is unclear. We examined the effect of acute vs. prolonged neurotrophin exposure on regulation of airway smooth muscle (ASM) intracellular Ca(2+) concentration ([Ca(2+)](i)): sarcoplasmic reticulum (SR) Ca(2+) release and Ca(2+) influx (specifically store-operated Ca(2+) entry, SOCE). Human ASM cells were incubated for 30 min in medium (control) or 1 or 10 nM BDNF, NT3, or NT4 (acute exposure) or overnight in 1 nM BDNF, NT3, or NT4 (prolonged exposure) and imaged after loading with the Ca(2+) indicator fura-2 AM. [Ca(2+)](i) responses to ACh, histamine, bradykinin, and caffeine and SOCE following SR Ca(2+) depletion were compared across cell groups. Force measurements were performed in human bronchial strips exposed to neurotrophins. Basal [Ca(2+)](i), peak responses to all agonists, SOCE, and force responses to ACh and histamine were all significantly enhanced by both acute and prolonged BDNF exposure (smaller effect of NT4) but decreased by NT3. Inhibition of the BDNF/NT4 receptor trkB by K252a prevented enhancement of [Ca(2+)](i) responses. ASM cells showed positive immunostaining for BDNF, NT3, NT4, trkB, and trkC (NT3 receptor). These novel data demonstrate that neurotrophins influence ASM [Ca(2+)](i) and force regulation and suggest a potential role for neurotrophins in airway diseases.
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Affiliation(s)
- Y S Prakash
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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48
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Cui Q. Actions of neurotrophic factors and their signaling pathways in neuronal survival and axonal regeneration. Mol Neurobiol 2006; 33:155-79. [PMID: 16603794 DOI: 10.1385/mn:33:2:155] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 11/30/1999] [Accepted: 08/15/2005] [Indexed: 02/05/2023]
Abstract
Adult axons in the mammalian central nervous system do not elicit spontaneous regeneration after injury, although many affected neurons have survived the neurotrauma. However, axonal regeneration does occur under certain conditions. These conditions include: (a) modification of regrowth environment, such as supply of peripheral nerve bridges and transplantation of Schwann cells or olfactory ensheathing glia to the injury site; (b) application of neurotrophic factors at the cell soma and axon tips; (c) blockade of growth-inhibitory molecules such as Nogo-A, myelin-associated glycoprotein, and oligodendrocyte-myelin glycoprotein; (d) prevention of chondroitin-sulfate-proteoglycans-related scar tissue formation at the injury site using chondroitinase ABC; and (e) elevation of intrinsic growth potential of injured neurons via increasing intracellular cyclic adenosine monophosphate level. A large body of evidence suggests that these conditions achieve enhanced neuronal survival and axonal regeneration through sometimes overlapping and sometimes distinct signal transduction mechanisms, depending on the targeted neuronal populations and intervention circumstances. This article reviews the available information on signal transduction pathways underlying neurotrophic-factor-mediated neuronal survival and neurite outgrowth/axonal regeneration. Better understanding of signaling transduction is important in helping us develop practical therapeutic approaches for encouraging neuronal survival and axonal regeneration after traumatic injury in clinical context.
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Affiliation(s)
- Qi Cui
- Laboratory for Neural Repair, Shantou University Medical College, China.
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49
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Lopez GF, Krimm RF. Epithelial overexpression of BDNF and NT4 produces distinct gustatory axon morphologies that disrupt initial targeting. Dev Biol 2006; 292:457-68. [PMID: 16500639 PMCID: PMC1939808 DOI: 10.1016/j.ydbio.2006.01.021] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2005] [Revised: 01/19/2006] [Accepted: 01/20/2006] [Indexed: 01/19/2023]
Abstract
Most fungiform taste buds fail to become innervated when BDNF or NT4 is overexpressed in the basal layer of tongue epithelium. Here, we examined when and how overexpression of BDNF and NT4 disrupt innervation to fungiform papillae. Overexpression of either factor disrupted chorda tympani innervation patterns either before or during the initial innervation of fungiform papillae. NT4 and BDNF overexpression each disrupted initial innervation by producing different gustatory axon morphologies that emerge at distinct times (E12.5 and E14.5, respectively). Chorda tympani nerve branching was reduced in NT4 overexpressing mice, and neuronal fibers in these mice were fasciculated and remained below the epithelial surface, as if repelled by NT4 overexpression. In contrast, many chorda tympani nerve branches were observed near the epithelial surface in mice overexpressing BDNF, and most were attracted to and invaded non-taste filiform papillae instead of gustatory papillae. These results suggest that BDNF, but not NT4, normally functions as a chemoattractant that allows chorda tympani fibers to distinguish their fungiform papillae targets from non-gustatory epithelium. Since BDNF and NT4 both signal through the p75 and TrkB receptors, trophin-specific activation of different internal signaling pathways must regulate the development of the distinct gustatory axon morphologies in neurotrophin-overexpressing mice.
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Affiliation(s)
| | - Robin F. Krimm
- * Corresponding author. Fax: +1 502 852 6228. E-mail address: (R.F. Krimm)
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50
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Chen ZY, Ieraci A, Teng H, Dall H, Meng CX, Herrera DG, Nykjaer A, Hempstead BL, Lee FS. Sortilin controls intracellular sorting of brain-derived neurotrophic factor to the regulated secretory pathway. J Neurosci 2006; 25:6156-66. [PMID: 15987945 PMCID: PMC1201519 DOI: 10.1523/jneurosci.1017-05.2005] [Citation(s) in RCA: 300] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF), after activity-dependent secretion from neurons, modulates critical nervous system functions. Recently, a variant in the human bdnf gene, resulting in a valine to methionine substitution in the prodomain, has been shown to lead to defective regulated secretion from neurons and memory impairment. Here, we report a novel function for a Vps10p domain protein, sortilin, in controlling BDNF sorting to the regulated secretory pathway. Sortilin interacts specifically with BDNF in a region encompassing the methionine substitution and colocalizes with BDNF in secretory granules in neurons. A truncated form of sortilin causes BDNF missorting to the constitutive secretory pathway without affecting neurotrophin-4 (NT-4) secretion. In addition, sortilin small interfering RNA introduced into primary neurons also led to BDNF missorting from the regulated to the constitutive secretory pathway. Together, these data suggest a mechanism to understand the defect associated with variant BDNF and provide a framework, based on divergent presynaptic regulation of sorting to secretory pathways, to explain how two ligands for tropomyosin-related kinase B, BDNF and NT-4, can mediate diverse biological responses.
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Affiliation(s)
- Zhe-Yu Chen
- Department of Psychiatry, Department of Medicine, Weill Medical College of Cornell University, New York, New York 10021, USA
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