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Seyed-Razavi Y, Kenyon BM, Qiu F, Harris DL, Hamrah P. A novel animal model of neuropathic corneal pain-the ciliary nerve constriction model. Front Neurosci 2023; 17:1265708. [PMID: 38144209 PMCID: PMC10749205 DOI: 10.3389/fnins.2023.1265708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 11/17/2023] [Indexed: 12/26/2023] Open
Abstract
Introduction Neuropathic pain arises as a result of peripheral nerve injury or altered pain processing within the central nervous system. When this phenomenon affects the cornea, it is referred to as neuropathic corneal pain (NCP), resulting in pain, hyperalgesia, burning, and photoallodynia, severely affecting patients' quality of life. To date there is no suitable animal model for the study of NCP. Herein, we developed an NCP model by constriction of the long ciliary nerves innervating the eye. Methods Mice underwent ciliary nerve constriction (CNC) or sham procedures. Safety was determined by corneal fluorescein staining to assess ocular surface damage, whereas Cochet-Bonnet esthesiometry and confocal microscopy assessed the function and structure of corneal nerves, respectively. Efficacy was assessed by paw wipe responses within 30 seconds of applying hyperosmolar (5M) saline at Days 3, 7, 10, and 14 post-constriction. Additionally, behavior was assessed in an open field test (OFT) at Days 7, 14, and 21. Results CNC resulted in significantly increased response to hyperosmolar saline between groups (p < 0.0001), demonstrating hyperalgesia and induction of neuropathic pain. Further, animals that underwent CNC had increased anxiety-like behavior in an open field test compared to controls at the 14- and 21-Day time-points (p < 0.05). In contrast, CNC did not result in increased corneal fluorescein staining or decreased sensation as compared to sham controls (p > 0.05). Additionally, confocal microscopy of corneal whole-mounts revealed that constriction resulted in only a slight reduction in corneal nerve density (p < 0.05), compared to naïve and sham groups. Discussion The CNC model induces a pure NCP phenotype and may be a useful model for the study of NCP, recapitulating features of NCP, including hyperalgesia in the absence of ocular surface damage, and anxiety-like behavior.
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Affiliation(s)
- Yashar Seyed-Razavi
- Center for Translational Ocular Immunology, Tufts Medical Center, Boston, MA, United States
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, United States
| | - Brendan M. Kenyon
- Center for Translational Ocular Immunology, Tufts Medical Center, Boston, MA, United States
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, United States
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University, Boston, MA, United States
| | - Fangfang Qiu
- Center for Translational Ocular Immunology, Tufts Medical Center, Boston, MA, United States
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, United States
| | - Deshea L. Harris
- Center for Translational Ocular Immunology, Tufts Medical Center, Boston, MA, United States
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, United States
| | - Pedram Hamrah
- Center for Translational Ocular Immunology, Tufts Medical Center, Boston, MA, United States
- Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, United States
- Program in Neuroscience, Graduate School of Biomedical Sciences, Tufts University, Boston, MA, United States
- Departments of Neuroscience and Immunology, Tufts University School of Medicine, Boston, MA, United States
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Timalsina B, Haque MN, Dash R, Choi HJ, Ghimire N, Moon IS. Neuronal Differentiation and Outgrowth Effect of Thymol in Trachyspermum ammi Seed Extract via BDNF/TrkB Signaling Pathway in Prenatal Maternal Supplementation and Primary Hippocampal Culture. Int J Mol Sci 2023; 24:ijms24108565. [PMID: 37239909 DOI: 10.3390/ijms24108565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/06/2023] [Accepted: 05/09/2023] [Indexed: 05/28/2023] Open
Abstract
Reviving the neuronal functions in neurodegenerative disorders requires the promotion of neurite outgrowth. Thymol, which is a principal component of Trachyspermum ammi seed extract (TASE), is reported to have neuroprotective effects. However, the effects of thymol and TASE on neuronal differentiation and outgrowth are yet to be studied. This study is the first report investigating the neuronal growth and maturation effects of TASE and thymol. Pregnant mice were orally supplemented with TASE (250 and 500 mg/kg), thymol (50 and 100 mg/kg), vehicle, and positive controls. The supplementation significantly upregulated the expression of brain-derived neurotrophic factor (BDNF) and early neuritogenesis markers in the pups' brains at post-natal day 1 (P1). Similarly, the BDNF level was significantly upregulated in the P12 pups' brains. Furthermore, TASE (75 and 100 µg/mL) and thymol (10 and 20 µM) enhanced the neuronal polarity, early neurite arborization, and maturation of hippocampal neurons in a dose-dependent manner in primary hippocampal cultures. The stimulatory activities of TASE and thymol on neurite extension involved TrkB signaling, as evidenced by attenuation via ANA-12 (5 µM), which is a specific TrkB inhibitor. Moreover, TASE and thymol rescued the nocodazole-induced blunted neurite extension in primary hippocampal cultures, suggesting their role as a potent microtubule stabilizing agent. These findings demonstrate the potent capacities of TASE and thymol in promoting neuronal development and reconstruction of neuronal circuitry, which are often compromised in neurodegenerative diseases and acute brain injuries.
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Affiliation(s)
- Binod Timalsina
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea
| | - Md Nazmul Haque
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea
- Department of Fisheries Biology and Genetics, Patuakhali Science and Technology University, Patuakhali 8602, Bangladesh
| | - Raju Dash
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea
| | - Ho Jin Choi
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea
| | - Nisha Ghimire
- Department of Life Science and Biochemical Engineering, Graduate School, Sun Moon University, Asan 31460, Republic of Korea
| | - Il Soo Moon
- Department of Anatomy, Dongguk University College of Medicine, Gyeongju 38066, Republic of Korea
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Nomdedeu-Sancho G, Alsina B. Wiring the senses: Factors that regulate peripheral axon pathfinding in sensory systems. Dev Dyn 2023; 252:81-103. [PMID: 35972036 PMCID: PMC10087148 DOI: 10.1002/dvdy.523] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 01/04/2023] Open
Abstract
Sensory neurons of the head are the ones that transmit the information about the external world to our brain for its processing. Axons from cranial sensory neurons sense different chemoattractant and chemorepulsive molecules during the journey and in the target tissue to establish the precise innervation with brain neurons and/or receptor cells. Here, we aim to unify and summarize the available information regarding molecular mechanisms guiding the different afferent sensory axons of the head. By putting the information together, we find the use of similar guidance cues in different sensory systems but in distinct combinations. In vertebrates, the number of genes in each family of guidance cues has suffered a great expansion in the genome, providing redundancy, and robustness. We also discuss recently published data involving the role of glia and mechanical forces in shaping the axon paths. Finally, we highlight the remaining questions to be addressed in the field.
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Affiliation(s)
- Gemma Nomdedeu-Sancho
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, Barcelona, Spain
| | - Berta Alsina
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, Barcelona, Spain
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Ardianto C, Shen R, Barus JF, Sasmita PK, Turana Y, Lilis L, Sidharta VM. Secretome as neuropathology-targeted intervention of Parkinson’s disease. Regen Ther 2022; 21:288-293. [PMID: 36092507 PMCID: PMC9441294 DOI: 10.1016/j.reth.2022.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/17/2022] [Accepted: 08/04/2022] [Indexed: 12/05/2022] Open
Abstract
Parkinson’s disease (PD) is the second most common progressive neurodegenerative disease, characterized by apoptosis of dopaminergic neurons in substansia nigra pars compacta (SNpc) caused by ⍺-synuclein aggregation. The use of secretomes released by medicinal signaling cells (MSCs) is one the promising preventive approaches that target several mechanisms in the neuropathology of PD. Its components target the lack of neurotrophin factors, proteasome dysfunction, oxidative stress, mitochondrial dysfunction, and at last neuroinflammation via several pathways. The complex and obscure pathology of PD induce the difficulty of the search of potential preventive approach for this disease. We described the potential of secretome of MSC as the novel preventive approach for PD, especially by targeting the said major pathogenesis of PD. Secretome targets the major pathogenesis of PD. Secretome regulates inflammation by balancing pro- and anti-inflammatory cytokines. Secretome induces autophagy providing cytoprotective effects. Secretome has anti-oxidative, neuroprotective, and neurotrophic due to neurotrophic factors as its component.
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Affiliation(s)
- Christian Ardianto
- Department of Histology, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Indonesia
- Master Program in Biomedical Sciences, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Indonesia
| | - Robert Shen
- Master Program in Biomedical Sciences, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Indonesia
| | - Jimmy F.A. Barus
- Master Program in Biomedical Sciences, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Indonesia
- Department of Neurology, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Indonesia
| | - Poppy Kristina Sasmita
- Department of Anatomy, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Indonesia
| | - Yuda Turana
- Department of Neurology, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Indonesia
| | - Lilis Lilis
- Department of Anatomical Pathology, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Indonesia
| | - Veronika Maria Sidharta
- Department of Histology, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Indonesia
- Master Program in Biomedical Sciences, School of Medicine and Health Sciences, Atma Jaya Catholic University of Indonesia, Indonesia
- Corresponding author. Jalan Pluit Raya No. 2, Pluit, Jakarta Utara, Indonesia,
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Fritzsch B, Elliott KL, Yamoah EN. Neurosensory development of the four brainstem-projecting sensory systems and their integration in the telencephalon. Front Neural Circuits 2022; 16:913480. [PMID: 36213204 PMCID: PMC9539932 DOI: 10.3389/fncir.2022.913480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 08/23/2022] [Indexed: 11/18/2022] Open
Abstract
Somatosensory, taste, vestibular, and auditory information is first processed in the brainstem. From the brainstem, the respective information is relayed to specific regions within the cortex, where these inputs are further processed and integrated with other sensory systems to provide a comprehensive sensory experience. We provide the organization, genetics, and various neuronal connections of four sensory systems: trigeminal, taste, vestibular, and auditory systems. The development of trigeminal fibers is comparable to many sensory systems, for they project mostly contralaterally from the brainstem or spinal cord to the telencephalon. Taste bud information is primarily projected ipsilaterally through the thalamus to reach the insula. The vestibular fibers develop bilateral connections that eventually reach multiple areas of the cortex to provide a complex map. The auditory fibers project in a tonotopic contour to the auditory cortex. The spatial and tonotopic organization of trigeminal and auditory neuron projections are distinct from the taste and vestibular systems. The individual sensory projections within the cortex provide multi-sensory integration in the telencephalon that depends on context-dependent tertiary connections to integrate other cortical sensory systems across the four modalities.
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Affiliation(s)
- Bernd Fritzsch
- Department of Biology, The University of Iowa, Iowa City, IA, United States
- Department of Otolaryngology, The University of Iowa, Iowa City, IA, United States
- *Correspondence: Bernd Fritzsch,
| | - Karen L. Elliott
- Department of Biology, The University of Iowa, Iowa City, IA, United States
| | - Ebenezer N. Yamoah
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, Reno, NV, United States
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The Role of Neurotrophin-4/Forkhead Box L1 in the Development of Nonsmall-Cell Lung Cancer. CONTRAST MEDIA & MOLECULAR IMAGING 2022; 2022:9078012. [PMID: 36034210 PMCID: PMC9381233 DOI: 10.1155/2022/9078012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/06/2022] [Accepted: 07/13/2022] [Indexed: 11/18/2022]
Abstract
This study aims to uncover the biological function of neurotrophin-4 (NTF4) in affecting the progression of nonsmall-cell lung cancer (NSCLC). NTF4 levels in NSCLC and paracancerous tissues were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Knockdown of NTF4 in A549 and H1299 cells was achieved by transfection of sh-NTF4. Subsequently, proliferative and migratory changes in NSCLC cells with NTF4 knockdown were determined by cell counting kit-8 (CCK-8) and transwell and wound healing assay. The target gene binding NTF4 was predicted by bioinformatic software and verified by a dual-luciferase reporter assay. The role of the NTF4/FOXL1 axis in mediating NSCLC cell behaviors was finally explored through rescue experiments. NTF4 was highly expressed in NSCLC tissues than in normal ones. Knockdown of NTF4 remarkably reduced proliferative and migratory rates in A549 and H1299 cells. Forkhead Box L1 (FOXL1) was confirmed as a target gene of NTF4 by bioinformatic software and verified by a dual-luciferase reporter assay. Knockdown of FOXL1 was able to reverse the reduced proliferative and migratory rates in A549 and H1299 cells transfected with sh-NTF4. NTF4 triggers NSCLC to proliferate and migrate via negatively regulating FOXL1.
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Honeycutt SE, N'Guetta PEY, O'Brien LL. Innervation in organogenesis. Curr Top Dev Biol 2022; 148:195-235. [PMID: 35461566 PMCID: PMC10636594 DOI: 10.1016/bs.ctdb.2022.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Proper innervation of peripheral organs helps to maintain physiological homeostasis and elicit responses to external stimuli. Disruptions to normal function can result in pathophysiological consequences. The establishment of connections and communication between the central nervous system and the peripheral organs is accomplished through the peripheral nervous system. Neuronal connections with target tissues arise from ganglia partitioned throughout the body. Organ innervation is initiated during development with stimuli being conducted through several types of neurons including sympathetic, parasympathetic, and sensory. While the physiological modulation of mature organs by these nerves is largely understood, their role in mammalian development is only beginning to be uncovered. Interactions with cells in target tissues can affect the development and eventual function of several organs, highlighting their significance. This chapter will cover the origin of peripheral neurons, factors mediating organ innervation, and the composition and function of organ-specific nerves during development. This emerging field aims to identify the functional contribution of innervation to development which will inform future investigations of normal and abnormal mammalian organogenesis, as well as contribute to regenerative and organ replacement efforts where nerve-derived signals may have significant implications for the advancement of such studies.
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Affiliation(s)
- Samuel E Honeycutt
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Pierre-Emmanuel Y N'Guetta
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Lori L O'Brien
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
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Huang T, Ohman LC, Clements AV, Whiddon ZD, Krimm RF. Variable Branching Characteristics of Peripheral Taste Neurons Indicates Differential Convergence. J Neurosci 2021; 41:4850-4866. [PMID: 33875572 PMCID: PMC8260161 DOI: 10.1523/jneurosci.1935-20.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 03/26/2021] [Accepted: 04/10/2021] [Indexed: 11/21/2022] Open
Abstract
Taste neurons are functionally and molecularly diverse, but their morphologic diversity remains completely unexplored. Using sparse cell genetic labeling, we provide the first reconstructions of peripheral taste neurons. The branching characteristics across 96 taste neurons show surprising diversity in their complexities. Individual neurons had 1-17 separate arbors entering between one and seven taste buds, 18 of these neurons also innervated non-taste epithelia. Axon branching characteristics are similar in gustatory neurons from male and female mice. Cluster analysis separated the neurons into four groups according to branch complexity. The primary difference between clusters was the amount of the nerve fiber within the taste bud available to contact taste-transducing cells. Consistently, we found that the maximum number of taste-transducing cells capable of providing convergent input onto individual gustatory neurons varied with a range of 1-22 taste-transducing cells. Differences in branching characteristics across neurons indicate that some neurons likely receive input from a larger number of taste-transducing cells than other neurons (differential convergence). By dividing neurons into two groups based on the type of taste-transducing cell most contacted, we found that neurons contacting primarily sour transducing cells were more heavily branched than those contacting primarily sweet/bitter/umami transducing cells. This suggests that neuron morphologies may differ across functional taste quality. However, the considerable remaining variability within each group also suggests differential convergence within each functional taste quality. Each possibility has functional implications for the system.SIGNIFICANCE STATEMENT Taste neurons are considered relay cells, communicating information from taste-transducing cells to the brain, without variation in morphology. By reconstructing peripheral taste neuron morphologies for the first time, we found that some peripheral gustatory neurons are simply branched, and can receive input from only a few taste-transducing cells. Other taste neurons are heavily branched, contacting many more taste-transducing cells than simply branched neurons. Based on the type of taste-transducing cell contacted, branching characteristics are predicted to differ across (and within) quality types (sweet/bitter/umami vs sour). Therefore, functional differences between neurons likely depends on the number of taste-transducing cells providing input and not just the type of cell providing input.
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Affiliation(s)
- Tao Huang
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky 40202
| | - Lisa C Ohman
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky 40202
| | - Anna V Clements
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky 40202
| | - Zachary D Whiddon
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky 40202
| | - Robin F Krimm
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky 40202
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Rios-Pilier J, Krimm RF. TrkB expression and dependence divides gustatory neurons into three subpopulations. Neural Dev 2019; 14:3. [PMID: 30691513 PMCID: PMC6350382 DOI: 10.1186/s13064-019-0127-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 01/07/2019] [Indexed: 01/01/2023] Open
Abstract
Background During development, gustatory (taste) neurons likely undergo numerous changes in morphology and expression prior to differentiation into maturity, but little is known this process or the factors that regulate it. Neuron differentiation is likely regulated by a combination of transcription and growth factors. Embryonically, most geniculate neuron development is regulated by the growth factor brain derived neurotrophic factor (BDNF). Postnatally, however, BDNF expression becomes restricted to subpopulations of taste receptor cells with specific functions. We hypothesized that during development, the receptor for BDNF, tropomyosin kinase B receptor (TrkB), may also become developmentally restricted to a subset of taste neurons and could be one factor that is differentially expressed across taste neuron subsets. Methods We used transgenic mouse models to label both geniculate neurons innervating the oral cavity (Phox2b+), which are primarily taste, from those projecting to the outer ear (auricular neurons) to label TrkB expressing neurons (TrkBGFP). We also compared neuron number, taste bud number, and taste receptor cell types in wild-type animals and conditional TrkB knockouts. Results Between E15.5-E17.5, TrkB receptor expression becomes restricted to half of the Phox2b + neurons. This TrkB downregulation was specific to oral cavity projecting neurons, since TrkB expression remained constant throughout development in the auricular geniculate neurons (Phox2b-). Conditional TrkB removal from oral sensory neurons (Phox2b+) reduced this population to 92% of control levels, indicating that only 8% of these neurons do not depend on TrkB for survival during development. The remaining neurons failed to innervate any remaining taste buds, 14% of which remained despite the complete loss of innervation. Finally, some types of taste receptor cells (Car4+) were more dependent on innervation than others (PLCβ2+). Conclusions Together, these findings indicate that TrkB expression and dependence divides gustatory neurons into three subpopulations: 1) neurons that always express TrkB and are TrkB-dependent during development (50%), 2) neurons dependent on TrkB during development but that downregulate TrkB expression between E15.5 and E17.5 (41%), and 3) neurons that never express or depend on TrkB (9%). These TrkB-independent neurons are likely non-gustatory, as they do not innervate taste buds.
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Affiliation(s)
- Jennifer Rios-Pilier
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, 511 S. Floyd St., MDR Building Room 111, Louisville, KY, 40202, USA
| | - Robin F Krimm
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, 511 S. Floyd St., MDR Building Room 111, Louisville, KY, 40202, USA.
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Chong PN, Sangu M, Huat TJ, Reza F, Begum T, Yusoff AAM, Jaafar H, Abdullah JM. Trkb-IP3 Pathway Mediating Neuroprotection in Rat Hippocampal Neuronal Cell Culture Following Induction of Kainic Acid. Malays J Med Sci 2018; 25:28-45. [PMID: 30914877 PMCID: PMC6422567 DOI: 10.21315/mjms2018.25.6.4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/17/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Following brain injury, development of hippocampal sclerosis often led to the temporal lobe epilepsy which is sometimes resistant to common anti-epileptic drugs. Cellular and molecular changes underlying epileptogenesis in animal models were studied, however, the underlying mechanisms of kainic acid (KA) mediated neuronal damage in rat hippocampal neuron cell culture alone has not been elucidated yet. METHODS Embryonic day 18 (E-18) rat hippocampus neurons were cultured with poly-L-lysine coated glass coverslips. Following optimisation, KA (0.5 μM), a chemoconvulsant agent, was administered at three different time-points (30, 60 and 90 min) to induce seizure in rat hippocampal neuronal cell culture. We examined cell viability, neurite outgrowth density and immunoreactivity of the hippocampus neuron culture by measuring brain derived neurotrophic factor (BDNF), γ-amino butyric acid A (GABAA) subunit α-1 (GABRA1), tyrosine receptor kinase B (TrkB), and inositol trisphosphate receptor (IP3R/IP3) levels. RESULTS The results revealed significantly decreased and increased immunoreactivity changes in TrkB (a BDNF receptor) and IP3R, respectively, at 60 min time point. CONCLUSION The current findings suggest that TrkB and IP3 could have a neuroprotective role which could be a potential pharmacological target for anti-epilepsy drugs.
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Affiliation(s)
- Pei Nei Chong
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Muthuraju Sangu
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Tee Jong Huat
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Faruque Reza
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Tahamina Begum
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Abdul Aziz Mohamed Yusoff
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Hasnan Jaafar
- Department of Pathology, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Jafri Malin Abdullah
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
- Centre for Neuroscience Services and Research, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
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Kazuno A, Maki D, Yamato I, Nakajima N, Seta H, Soeda S, Ozawa S, Uchiyama Y, Tamaki T. Regeneration of Transected Recurrent Laryngeal Nerve Using Hybrid-Transplantation of Skeletal Muscle-Derived Stem Cells and Bioabsorbable Scaffold. J Clin Med 2018; 7:jcm7090276. [PMID: 30213120 PMCID: PMC6162854 DOI: 10.3390/jcm7090276] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/05/2018] [Accepted: 09/09/2018] [Indexed: 12/31/2022] Open
Abstract
Hybrid transplantation of skeletal muscle-derived multipotent stem cells (Sk-MSCs) and bioabsorbable polyglyconate (PGA) felt was studied as a novel regeneration therapy for the transected recurrent laryngeal nerve (RLN). Sk-MSCs were isolated from green fluorescence protein transgenic mice and then expanded and transplanted with PGA felt for the hybrid transplantation (HY group) into the RLN transected mouse model. Transplantation of culture medium (M group) and PGA + medium (PGA group) were examined as controls. After eight weeks, trans-oral video laryngoscopy demonstrated 80% recovery of spontaneous vocal-fold movement during breathing in the HY group, whereas the M and PGA groups showed wholly no recoveries. The Sk-MSCs showed active engraftment confined to the damaged RLN portion, representing favorable prevention of cell diffusion on PGA, with an enhanced expression of nerve growth factor mRNAs. Axonal re-connection in the HY group was confirmed by histological serial sections. Immunohistochemical analysis revealed the differentiation of Sk-MSCs into Schwann cells and perineurial/endoneurial cells and axonal growth supportive of perineurium/endoneurium. The number of axons recovered was over 86%. These results showed that the stem cell and cytokine delivery system using hybrid transplantation of Sk-MSCs/PGA-felt is a potentially practical and useful approach for the recovery of transected RLN.
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Affiliation(s)
- Akihito Kazuno
- Department of Gastroenterological Surgery, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
- Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
| | - Daisuke Maki
- Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
- Department of Otolaryngology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
| | - Ippei Yamato
- Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
- Department of Medical Education, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
| | - Nobuyuki Nakajima
- Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
- Department of Urology, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
| | - Hiroya Seta
- Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
| | - Shuichi Soeda
- Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
| | - Soji Ozawa
- Department of Gastroenterological Surgery, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
| | - Yoshiyasu Uchiyama
- Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
- Department of Orthopedics, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
| | - Tetsuro Tamaki
- Muscle Physiology & Cell Biology Unit, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
- Department of Human Structure and Function, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan.
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Maintenance of Mouse Gustatory Terminal Field Organization Is Dependent on BDNF at Adulthood. J Neurosci 2018; 38:6873-6887. [PMID: 29954852 DOI: 10.1523/jneurosci.0802-18.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/26/2018] [Accepted: 06/17/2018] [Indexed: 01/19/2023] Open
Abstract
The rodent peripheral gustatory system is especially plastic during early postnatal development and maintains significant anatomical plasticity into adulthood. Thus, taste information carried from the tongue to the brain is built and maintained on a background of anatomical circuits that have the capacity to change throughout the animal's lifespan. Recently, the neurotrophin brain-derived neurotrophic factor (BDNF) was shown to be required in the tongue to maintain normal levels of innervation in taste buds at adulthood, indicating that BDNF is a key molecule in the maintenance of nerve/target matching in taste buds. Here, we tested whether maintenance of the central process of these gustatory nerves at adulthood also relies on BDNF by using male and female transgenic mice with inducible CreERT2 under the control of the keratin 14 promoter or under control of the ubiquitin promoter to remove Bdnf from the tongue or from all tissues, respectively. We found that the terminal fields of gustatory nerves in the nucleus of the solitary tract were expanded when Bdnf was removed from the tongue at adulthood and with even larger and more widespread changes in mice where Bdnf was removed from all tissues. Removal of Bdnf did not affect numbers of ganglion cells that made up the nerves and did not affect peripheral, whole-nerve taste responses. We conclude that normal expression of Bdnf in gustatory structures is required to maintain normal levels of innervation at adulthood and that the central effects of Bdnf removal are opposite of those in the tongue.SIGNIFICANCE STATEMENT BDNF plays a major role in the development and maintenance of proper innervation of taste buds. However, the importance of BDNF in maintaining innervation patterns of gustatory nerves into central targets has not been assessed. Here, we tested whether Bdnf removal from the tongue or from all structures in adult mice impacts the maintenance of how taste nerves project to the first central relay. Deletion of Bdnf from the tongue and from all tissues led to a progressively greater expansion of terminal fields. This demonstrates, for the first time, that BDNF is necessary for the normal maintenance of central gustatory circuits at adulthood and further highlights a level of plasticity not seen in other sensory system subcortical circuits.
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Li F, Niu B, Zhu M. Ablation of NTPDase2+ cells inhibits the formation of filiform papillae in tongue tip. Animal Model Exp Med 2018; 1:143-151. [PMID: 30891559 PMCID: PMC6388074 DOI: 10.1002/ame2.12021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 05/31/2018] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Lingual epithelia in the tongue tip are among the most rapidly regenerating tissues, but the mechanism of cell genesis in this tissue is still unknown. Previous study has suggested the existence of multiple stem cell pools in lingual epithelia and papillae. Like K14+ and Sox2+ cells, NTPDase2+ cells have characteristics of stem cells. METHODS We employed a system using doxycycline to conditionally ablate NTPDase2+ cells in lingual epithelia and papillae by regulated expression of the diphtheria toxin A (DTA) gene. Transgenic lines, which expressed the rtTA gene in NTPDase2+ cells, were produced by pronuclear injection of zygotes from C57BL/6 mice using the BAC clone RP23-47P18. The NTPDase2-rtTA transgenic mice were crossed with the TetO-DTA transgenic animals. The double transgenic mice were treated with doxycycline. Doxycycline (Dox) was diluted in 5% sucrose in water to a final concentration of 0.3-0.5 mg/mL and supplied as drinking water. RESULTS After 15 days of Dox induction, the expression of NTPDase2, Sox2 and K14 was ablated from lingual epithelia. DTA expression in NTPDase2+ cells did not inhibit the turnover of GNAT3+ or PLCβ2+ cells in taste buds, nor the expression of S100β beneath lingual epithelia and papillae. After 35 days ablation of NTPDase2+ cells, the basic structure of lingual epithelia and papillae remained intact. However, the ratio of cell to total tissue area was decreased in lingual epithelia and circumvallate (CV) papillae. DTA expression also inhibited the regeneration of filiform papillae on the dorsal surface of the tongue tip. CONCLUSIONS These studies provide important insights into the understanding of dynamic equilibrium among the multiple stem cell populations present in the lingual epithelia and papillae.
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Affiliation(s)
- Feng Li
- Department of Laboratory Animal ScienceShanghai Public Health Clinical CenterFudan UniversityShanghaiChina
| | - Bo‐Wen Niu
- Department of Laboratory Animal ScienceShanghai Public Health Clinical CenterFudan UniversityShanghaiChina
| | - Meng‐Min Zhu
- Department of Laboratory Animal ScienceShanghai Public Health Clinical CenterFudan UniversityShanghaiChina
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Maintenance of Mouse Gustatory Terminal Field Organization Is Disrupted following Selective Removal of Peripheral Sodium Salt Taste Activity at Adulthood. J Neurosci 2017; 37:7619-7630. [PMID: 28676575 DOI: 10.1523/jneurosci.3838-16.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 06/20/2017] [Accepted: 06/24/2017] [Indexed: 01/08/2023] Open
Abstract
Neural activity plays a critical role in the development of central circuits in sensory systems. However, the maintenance of these circuits at adulthood is usually not dependent on sensory-elicited neural activity. Recent work in the mouse gustatory system showed that selectively deleting the primary transduction channel for sodium taste, the epithelial sodium channel (ENaC), throughout development dramatically impacted the organization of the central terminal fields of three nerves that carry taste information to the nucleus of the solitary tract. More specifically, deleting ENaCs during development prevented the normal maturation of the fields. The present study was designed to extend these findings by testing the hypothesis that the loss of sodium taste activity impacts the maintenance of the normal adult terminal field organization in male and female mice. To do this, we used an inducible Cre-dependent genetic recombination strategy to delete ENaC function after terminal field maturation occurred. We found that removal of sodium taste neural activity at adulthood resulted in significant reorganization of mature gustatory afferent terminal fields in the nucleus of the solitary tract. Specifically, the chorda tympani and greater superficial petrosal nerve terminal fields were 1.4× and 1.6× larger than age-matched controls, respectively. By contrast, the glossopharyngeal nerve, which is not highly sensitive to sodium taste stimulation, did not undergo terminal field reorganization. These surprising results suggest that gustatory nerve terminal fields remain plastic well into adulthood, which likely impacts central coding of taste information and taste-related behaviors with altered taste experience.SIGNIFICANCE STATEMENT Neural activity plays a major role in the development of sensory circuits in the mammalian brain. However, the importance of sensory-driven activity in maintaining these circuits at adulthood, especially in subcortical structures, appears to be much less. Here, we tested whether the loss of sodium taste activity in adult mice impacts the maintenance of how taste nerves project to the first central relay. We found that specific loss of sodium-elicited taste activity at adulthood produced dramatic and selective reorganization of terminal fields in the brainstem. This demonstrates, for the first time, that taste-elicited activity is necessary for the normal maintenance of central gustatory circuits at adulthood and highlights a level of plasticity not seen in other sensory system subcortical circuits.
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15
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Hierarchy in the home cage affects behaviour and gene expression in group-housed C57BL/6 male mice. Sci Rep 2017; 7:6991. [PMID: 28765614 PMCID: PMC5539312 DOI: 10.1038/s41598-017-07233-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 06/26/2017] [Indexed: 01/26/2023] Open
Abstract
Group-housed male mice exhibit aggressive behaviour towards their cage mates and form a social hierarchy. Here, we describe how social hierarchy in standard group-housed conditions affects behaviour and gene expression in male mice. Four male C57BL/6 mice were kept in each cage used in the study, and the social hierarchy was determined from observation of video recordings of aggressive behaviour. After formation of a social hierarchy, the behaviour and hippocampal gene expression were analysed in the mice. Higher anxiety- and depression-like behaviours and elevated gene expression of hypothalamic corticotropin-releasing hormone and hippocampal serotonin receptor subtypes were observed in subordinate mice compared with those of dominant mice. These differences were alleviated by orally administering fluoxetine, which is an antidepressant of the selective serotonin reuptake inhibitor class. We concluded that hierarchy in the home cage affects behaviour and gene expression in male mice, resulting in anxiety- and depression-like behaviours being regulated differently in dominant and subordinate mice.
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16
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Selective Deletion of Sodium Salt Taste during Development Leads to Expanded Terminal Fields of Gustatory Nerves in the Adult Mouse Nucleus of the Solitary Tract. J Neurosci 2017; 37:660-672. [PMID: 28100747 DOI: 10.1523/jneurosci.2913-16.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/04/2016] [Accepted: 12/01/2016] [Indexed: 11/21/2022] Open
Abstract
Neuronal activity plays a key role in the development of sensory circuits in the mammalian brain. In the gustatory system, experimental manipulations now exist, through genetic manipulations of specific taste transduction processes, to examine how specific taste qualities (i.e., basic tastes) impact the functional and structural development of gustatory circuits. Here, we used a mouse knock-out model in which the transduction component used to discriminate sodium salts from other taste stimuli was deleted in taste bud cells throughout development. We used this model to test the hypothesis that the lack of activity elicited by sodium salt taste impacts the terminal field organization of nerves that carry taste information from taste buds to the nucleus of the solitary tract (NST) in the medulla. The glossopharyngeal, chorda tympani, and greater superficial petrosal nerves were labeled to examine their terminal fields in adult control mice and in adult mice in which the α-subunit of the epithelial sodium channel was conditionally deleted in taste buds (αENaC knockout). The terminal fields of all three nerves in the NST were up to 2.7 times greater in αENaC knock-out mice compared with the respective field volumes in control mice. The shapes of the fields were similar between the two groups; however, the density and spread of labels were greater in αENaC knock-out mice. Overall, our results show that disruption of the afferent taste signal to sodium salts disrupts the normal age-dependent "pruning" of all terminal fields, which could lead to alterations in sensory coding and taste-related behaviors. SIGNIFICANCE STATEMENT Neural activity plays a major role in the development of sensory circuits in the mammalian brain. To date, there has been no direct test of whether taste-elicited neural activity has a role in shaping central gustatory circuits. However, recently developed genetic tools now allow an assessment of how specific taste stimuli, in this case sodium salt taste, play a role in the maturation of the terminal fields in the mouse brainstem. We found that the specific deletion of sodium salt taste during development produced terminal fields in adults that were dramatically larger than in control mice, demonstrating for the first time that sodium salt taste-elicited activity is necessary for the normal maturation of gustatory inputs into the brain.
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17
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Tang T, Rios-Pilier J, Krimm R. Taste bud-derived BDNF maintains innervation of a subset of TrkB-expressing gustatory nerve fibers. Mol Cell Neurosci 2017; 82:195-203. [PMID: 28600222 DOI: 10.1016/j.mcn.2017.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 05/08/2017] [Accepted: 06/05/2017] [Indexed: 02/07/2023] Open
Abstract
Taste receptor cells transduce different types of taste stimuli and transmit this information to gustatory neurons that carry it to the brain. Taste receptor cells turn over continuously in adulthood, requiring constant new innervation from nerve fibers. Therefore, the maintenance of innervation to taste buds is an active process mediated by many factors, including brain-derived neurotrophic factor (BDNF). Specifically, 40% of taste bud innervation is lost when Bdnf is removed during adulthood. Here we speculated that not all gustatory nerve fibers express the BDNF receptor, TrkB, resulting in subsets of neurons that vary in their response to BDNF. However, it is also possible that the partial loss of innervation occurred because the Bdnf gene was not effectively removed. To test these possibilities, we first determined that not all gustatory nerve fibers express the TrkB receptor in adult mice. We then verified the efficiency of Bdnf removal specifically in taste buds of K14-CreER:Bdnf mice and found that Bdnf expression was reduced to 1%, indicating efficient Bdnf gene recombination. BDNF removal resulted in a 55% loss of TrkB-expressing nerve fibers, which was greater than the loss of P2X3-positive fibers (39%), likely because taste buds were innervated by P2X3+/TrkB- fibers that were unaffected by BDNF removal. We conclude that gustatory innervation consists of both TrkB-positive and TrkB-negative taste fibers and that BDNF is specifically important for maintaining TrkB-positive innervation to taste buds. In addition, although taste bud size was not affected by inducible Bdnf removal, the expression of the γ subunit of the ENaC channel was reduced. So, BDNF may regulate expression of some molecular components of taste transduction pathways.
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Affiliation(s)
- Tao Tang
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA
| | - Jennifer Rios-Pilier
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA
| | - Robin Krimm
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA.
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18
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Meng L, Huang T, Sun C, Hill DL, Krimm R. BDNF is required for taste axon regeneration following unilateral chorda tympani nerve section. Exp Neurol 2017; 293:27-42. [PMID: 28347764 DOI: 10.1016/j.expneurol.2017.03.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 03/22/2017] [Accepted: 03/23/2017] [Indexed: 12/18/2022]
Abstract
Taste nerves readily regenerate to reinnervate denervated taste buds; however, factors required for regeneration have not yet been identified. When the chorda tympani nerve is sectioned, expression of brain-derived neurotrophic factor (BDNF) remains high in the geniculate ganglion and lingual epithelium, despite the loss of taste buds. These observations suggest that BDNF is present in the taste system after nerve section and may support taste nerve regeneration. To test this hypothesis, we inducibly deleted Bdnf during adulthood in mice. Shortly after Bdnf gene recombination, the chorda tympani nerve was unilaterally sectioned causing a loss of both taste buds and neurons, irrespective of BDNF levels. Eight weeks after nerve section, however, regeneration was differentially affected by Bdnf deletion. In control mice, there was regeneration of the chorda tympani nerve and taste buds reappeared with innervation. In contrast, few taste buds were reinnervated in mice lacking normal Bdnf expression such that taste bud number remained low. In all genotypes, taste buds that were reinnervated were normal-sized, but non-innervated taste buds remained small and atrophic. On the side of the tongue contralateral to the nerve section, taste buds for some genotypes became larger and all taste buds remained innervated. Our findings suggest that BDNF is required for nerve regeneration following gustatory nerve section.
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Affiliation(s)
- Lingbin Meng
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA
| | - Tao Huang
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA
| | - Chengsan Sun
- Department of Psychology, University of Virginia, Charlottesville, VA 22904, USA
| | - David L Hill
- Department of Psychology, University of Virginia, Charlottesville, VA 22904, USA
| | - Robin Krimm
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA.
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19
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Treffy RW, Collins D, Hoshino N, Ton S, Katsevman GA, Oleksiak M, Runge EM, Cho D, Russo M, Spec A, Gomulka J, Henkemeyer M, Rochlin MW. Ephrin-B/EphB Signaling Is Required for Normal Innervation of Lingual Gustatory Papillae. Dev Neurosci 2016; 38:124-38. [PMID: 27035151 PMCID: PMC4927353 DOI: 10.1159/000444748] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 02/17/2016] [Indexed: 02/02/2023] Open
Abstract
The innervation of taste buds is an excellent model system for studying the guidance of axons during targeting because of their discrete nature and the high fidelity of innervation. The pregustatory epithelium of fungiform papillae is known to secrete diffusible axon guidance cues such as BDNF and Sema3A that attract and repel, respectively, geniculate ganglion axons during targeting, but diffusible factors alone are unlikely to explain how taste axon terminals are restricted to their territories within the taste bud. Nondiffusible cell surface proteins such as Ephs and ephrins can act as receptors and/or ligands for one another and are known to control axon terminal positioning in several parts of the nervous system, but they have not been studied in the gustatory system. We report that ephrin-B2 linked β-galactosidase staining and immunostaining was present along the dorsal epithelium of the mouse tongue as early as embryonic day 15.5 (E15.5), but was not detected at E14.5, when axons first enter the epithelium. Ephrin-B1 immunolabeling was barely detected in the epithelium and found at a somewhat higher concentration in the mesenchyme subjacent to the epithelium. EphB1 and EphB2 were detected in lingual sensory afferents in vivo and geniculate neurites in vitro. Ephrin-B1 and ephrin-B2 were similarly effective in repelling or suppressing outgrowth by geniculate neurites in vitro. These in vitro effects were independent of the neurotrophin used to promote outgrowth, but were reduced by elevated levels of laminin. In vivo, mice null for EphB1 and EphB2 exhibited decreased gustatory innervation of fungiform papillae. These data provide evidence that ephrin-B forward signaling is necessary for normal gustatory innervation of the mammalian tongue.
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20
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Insulin-Like Growth Factors Are Expressed in the Taste System, but Do Not Maintain Adult Taste Buds. PLoS One 2016; 11:e0148315. [PMID: 26901525 PMCID: PMC4762545 DOI: 10.1371/journal.pone.0148315] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/15/2016] [Indexed: 01/01/2023] Open
Abstract
Growth factors regulate cell growth and differentiation in many tissues. In the taste system, as yet unknown growth factors are produced by neurons to maintain taste buds. A number of growth factor receptors are expressed at greater levels in taste buds than in the surrounding epithelium and may be receptors for candidate factors involved in taste bud maintenance. We determined that the ligands of eight of these receptors were expressed in the E14.5 geniculate ganglion and that four of these ligands were expressed in the adult geniculate ganglion. Of these, the insulin-like growth factors (IGF1, IGF2) were expressed in the ganglion and their receptor, insulin-like growth factor receptor 1 (IGF1R), were expressed at the highest levels in taste buds. To determine whether IGF1R regulates taste bud number or structure, we conditionally eliminated IGF1R from the lingual epithelium of mice using the keratin 14 (K14) promoter (K14-Cre::Igf1rlox/lox). While K14-Cre::Igf1rlox/lox mice had significantly fewer taste buds at P30 compared with control mice (Igf1rlox/lox), this difference was not observed by P80. IGF1R removal did not affect taste bud size or cell number, and the number of phospholipase C β2- (PLCβ2) and carbonic anhydrase 4- (Car4) positive taste receptor cells did not differ between genotypes. Taste buds at the back of the tongue fungiform taste field were larger and contained more cells than those at the tongue tip, and these differences were diminished in K14-Cre::Igf1rlox/lox mice. The epithelium was thicker at the back versus the tip of the tongue, and this difference was also attenuated in K14-Cre::Igf1rlox/lox mice. We conclude that, although IGFs are expressed at high levels in the taste system, they likely play little or no role in maintaining adult taste bud structure. IGFs have a potential role in establishing the initial number of taste buds, and there may be limits on epithelial thickness in the absence of IGF1R signaling.
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Taste Bud-Derived BDNF Is Required to Maintain Normal Amounts of Innervation to Adult Taste Buds. eNeuro 2015; 2:eN-NWR-0097-15. [PMID: 26730405 PMCID: PMC4697083 DOI: 10.1523/eneuro.0097-15.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 11/29/2015] [Accepted: 11/30/2015] [Indexed: 11/26/2022] Open
Abstract
Gustatory neurons transmit chemical information from taste receptor cells, which reside in taste buds in the oral cavity, to the brain. As adult taste receptor cells are renewed at a constant rate, nerve fibers must reconnect with new taste receptor cells as they arise. Therefore, the maintenance of gustatory innervation to the taste bud is an active process. Understanding how this process is regulated is a fundamental concern of gustatory system biology. We speculated that because brain-derived neurotrophic factor (BDNF) is required for taste bud innervation during development, it might function to maintain innervation during adulthood. If so, taste buds should lose innervation when Bdnf is deleted in adult mice. To test this idea, we first removed Bdnf from all cells in adulthood using transgenic mice with inducible CreERT2 under the control of the Ubiquitin promoter. When Bdnf was removed, approximately one-half of the innervation to taste buds was lost, and taste buds became smaller because of the loss of taste bud cells. Individual taste buds varied in the amount of innervation each lost, and those that lost the most innervation also lost the most taste bud cells. We then tested the idea that that the taste bud was the source of this BDNF by reducing Bdnf levels specifically in the lingual epithelium and taste buds. Taste buds were confirmed as the source of BDNF regulating innervation. We conclude that BDNF expressed in taste receptor cells is required to maintain normal levels of innervation in adulthood.
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22
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Jia Z, Xue R, Ma S, Xu J, Guo S, Li S, Zhang E, Wang J, Yang J. Erythropoietin Attenuates the Memory Deficits in Aging Rats by Rescuing the Oxidative Stress and Inflammation and Promoting BDNF Releasing. Mol Neurobiol 2015; 53:5664-70. [DOI: 10.1007/s12035-015-9438-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 09/10/2015] [Indexed: 01/06/2023]
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Huang T, Ma L, Krimm RF. Postnatal reduction of BDNF regulates the developmental remodeling of taste bud innervation. Dev Biol 2015; 405:225-36. [PMID: 26164656 DOI: 10.1016/j.ydbio.2015.07.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 01/29/2023]
Abstract
The refinement of innervation is a common developmental mechanism that serves to increase the specificity of connections following initial innervation. In the peripheral gustatory system, the extent to which innervation is refined and how refinement might be regulated is unclear. The initial innervation of taste buds is controlled by brain-derived neurotrophic factor (BDNF). Following initial innervation, taste receptor cells are added and become newly innervated. The connections between the taste receptor cells and nerve fibers are likely to be specific in order to retain peripheral coding mechanisms. Here, we explored the possibility that the down-regulation of BDNF regulates the refinement of taste bud innervation during postnatal development. An analysis of BDNF expression in Bdnf(lacZ/+) mice and real-time reverse transcription polymerase chain reaction (RT-PCR) revealed that BDNF was down-regulated between postnatal day (P) 5 and P10. This reduction in BDNF expression was due to a loss of precursor/progenitor cells that express BDNF, while the expression of BDNF in the subpopulations of taste receptor cells did not change. Gustatory innervation, which was identified by P2X3 immunohistochemistry, was lost around the perimeter where most progenitor/precursor cells are located. In addition, the density of innervation in the taste bud was reduced between P5 and P10, because taste buds increase in size without increasing innervation. This reduction of innervation density was blocked by the overexpression of BDNF in the precursor/progenitor population of taste bud cells. Together these findings indicate that the process of BDNF restriction to a subpopulation of taste receptor cells between P5 and P10, results in a refinement of gustatory innervation. We speculate that this refinement results in an increased specificity of connections between neurons and taste receptor cells during development.
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Affiliation(s)
- Tao Huang
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA
| | - Liqun Ma
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA
| | - Robin F Krimm
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA.
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24
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Meng L, Jiang X, Ji R. Role of neurotrophin in the taste system following gustatory nerve injury. Metab Brain Dis 2015; 30:605-13. [PMID: 25381474 DOI: 10.1007/s11011-014-9626-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 10/30/2014] [Indexed: 12/12/2022]
Abstract
Taste system is a perfect system to study degeneration and regeneration after nerve injury because the taste system is highly plastic and the regeneration is robust. Besides, degeneration and regeneration can be easily measured since taste buds arise in discrete locations, and nerves that innervate them can be accurately quantified. Neurotrophins are a family of proteins that regulate neural survival, function, and plasticity after nerve injury. Recent studies have shown that neurotrophins play an important role in the developmental and mature taste system, indicating neurtrophin might also regulate taste system following gustatory nerve injury. This review will summarize how taste system degenerates and regenerates after gustatory nerve cut and conclude potential roles of neurotrophin in regulating the process.
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Affiliation(s)
- Lingbin Meng
- Department of Anatomical Sciences and Neurobiology, University of Louisville, School of Medicine, Louisville, KY, 40202, USA
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25
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Sun C, Dayal A, Hill DL. Expanded terminal fields of gustatory nerves accompany embryonic BDNF overexpression in mouse oral epithelia. J Neurosci 2015; 35:409-21. [PMID: 25568132 PMCID: PMC4287156 DOI: 10.1523/jneurosci.2381-14.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 10/28/2014] [Accepted: 11/14/2014] [Indexed: 11/21/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is expressed in gustatory epithelia and is required for gustatory neurons to locate and innervate their correct target during development. When BDNF is overexpressed throughout the lingual epithelium, beginning embryonically, chorda tympani fibers are misdirected and innervate inappropriate targets, leading to a loss of taste buds. The remaining taste buds are hyperinnervated, demonstrating a disruption of nerve/target matching in the tongue. We tested the hypothesis here that overexpression of BDNF peripherally leads to a disrupted terminal field organization of nerves that carry taste information to the brainstem. The chorda tympani, greater superficial petrosal, and glossopharyngeal nerves were labeled in adult wild-type (WT) mice and in adult mice in which BDNF was overexpressed (OE) to examine the volume and density of their central projections in the nucleus of the solitary tract. We found that the terminal fields of the chorda tympani and greater superficial petrosal nerves and overlapping fields that included these nerves in OE mice were at least 80% greater than the respective field volumes in WT mice. The shapes of terminal fields were similar between the two groups; however, the density and spread of labels were greater in OE mice. Unexpectedly, there were also group-related differences in chorda tympani nerve function, with OE mice showing a greater relative taste response to a concentration series of sucrose. Overall, our results show that disruption in peripheral innervation patterns of sensory neurons have significant effects on peripheral nerve function and central organization of their terminal fields.
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Affiliation(s)
- Chengsan Sun
- Department of Psychology, University of Virginia, Charlottesville, Virginia 22904, and
| | - Arjun Dayal
- Pritzker School of Medicine, University of Chicago, Chicago, Illinois 60637
| | - David L Hill
- Department of Psychology, University of Virginia, Charlottesville, Virginia 22904, and
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Fei D, Huang T, Krimm RF. The neurotrophin receptor p75 regulates gustatory axon branching and promotes innervation of the tongue during development. Neural Dev 2014; 9:15. [PMID: 24961238 PMCID: PMC4083039 DOI: 10.1186/1749-8104-9-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 05/28/2014] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT4) regulate the survival of gustatory neurons, axon growth and branching, and innervation of taste buds during development. These actions are largely, but not completely, mediated through the tyrosine kinase receptor, TrkB. Here, we investigated the role of p75, the other major receptor for BDNF and NT4, in the development of the taste system. RESULTS We found that p75-/-mice showed delayed axon outgrowth and reduced branching of gustatory axons at embryonic day (E)13.5. From E14.5 to E18.5, gustatory neurons innervated fewer papillae and completely failed to innervate the mid-region of the tongue in p75-/-mice. These early effects of the p75 mutation on gustatory axons preceded the loss of geniculate ganglion neurons starting at E14.5 and also contributed to a loss of taste buds at and after birth. Because knockouts for the TrkB receptor (TrkB-/-) do not lose as many taste buds as hybrid knockouts for its two ligands (BDNF and NT4), we asked if p75 maintains those additional taste buds in the absence of TrkB. It does not; hybrid TrkB-/-/p75-/-mice had more taste buds than TrkB-/-mice; these additional taste buds were not due to an increase in neurons or innervation. CONCLUSIONS p75 regulates gustatory neuron axon branching and tongue innervation patterns during taste system development. This function is likely accomplished independently of BDNF, NT4, and TrkB. In addition, p75 does not support the remaining neurons or taste buds in TrkB-/-mice.
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Affiliation(s)
| | | | - Robin F Krimm
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA.
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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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Fujita Y, Sato A, Yamashita T. Brimonidine promotes axon growth after optic nerve injury through Erk phosphorylation. Cell Death Dis 2013; 4:e763. [PMID: 23928702 PMCID: PMC3763459 DOI: 10.1038/cddis.2013.298] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/27/2013] [Accepted: 07/15/2013] [Indexed: 11/25/2022]
Abstract
It is well known that axons of the adult mammalian central nervous system have a very limited ability to regenerate after injury. Therefore, the neurodegenerative process of glaucoma results in irreversible functional deficits, such as blindness. Brimonidine (BMD) is an alpha2-adrenergic receptor agonist that is used commonly to lower intraocular pressure in glaucoma. Although it has been suggested that BMD has neuroprotective effects, the underlying mechanism remains unknown. In this study, we explored the molecular mechanism underlying the neuroprotective effect of BMD in an optic nerve injury (ONI) model. BMD treatment promoted optic nerve regeneration by inducing Erk1/2 phosphorylation after ONI. In addition, an Erk1/2 antagonist suppressed BMD-mediated axonal regeneration. A gene expression analysis revealed that the expression of the neurotrophin receptor gene p75 was increased and that the expression of the tropomyosin receptor kinase B (TrkB) gene was decreased after ONI. BMD treatment abrogated the changes in the expression of these genes. These results indicate that BMD promotes optic nerve regeneration via the activation of Erk1/2.
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Affiliation(s)
- Y Fujita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Osaka, Japan
- Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, 5 Sanbancho, Tokyo, Japan
| | - A Sato
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Osaka, Japan
- Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, 5 Sanbancho, Tokyo, Japan
| | - T Yamashita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Osaka, Japan
- Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, 5 Sanbancho, Tokyo, Japan
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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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Patel AV, Krimm RF. Neurotrophin-4 regulates the survival of gustatory neurons earlier in development using a different mechanism than brain-derived neurotrophic factor. Dev Biol 2012; 365:50-60. [PMID: 22353733 DOI: 10.1016/j.ydbio.2012.02.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Revised: 01/31/2012] [Accepted: 02/06/2012] [Indexed: 12/13/2022]
Abstract
The number of neurons in the geniculate ganglion that are available to innervate taste buds is regulated by neurotrophin-4 (NT-4) and brain-derived neurotrophic factor (BDNF). Our goal for the current study was to examine the timing and mechanism of NT-4-mediated regulation of geniculate neuron number during development. We discovered that NT-4 mutant mice lose 33% of their geniculate neuronal cells between E10.5 and E11.5. By E11.5, geniculate axons have just reached the tongue and do not yet innervate their gustatory targets; thus, NT-4 does not function as a target-derived growth factor. At E11.5, no difference was observed in proliferating cells or the rate at which cells exit the cell cycle between NT-4 mutant and wild type ganglia. Instead, there was an increase in TUNEL-labeling, indicating an increase in cell death in Ntf4(-/-) mice compared with wild types. However, activated caspase-3, which is up-regulated in the absence of BDNF, was not increased. This finding indicates that cell death initiated by NT-4-removal occurs through a different cell death pathway than BDNF-removal. We observed no additional postnatal loss of taste buds or neurons in Ntf4(-/-) mice. Thus, during early embryonic development, NT-4 produced in the ganglion and along the projection pathway inhibits cell death through an activated caspase-3 independent mechanism. Therefore, compared to BDNF, NT-4 plays distinct roles in gustatory development; differences include timing, source of neurotrophin, and mechanism of action.
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Affiliation(s)
- Ami V Patel
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
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