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Jassim AH, Cavanaugh M, Shah JS, Willits R, Inman DM. Transcorneal Electrical Stimulation Reduces Neurodegenerative Process in a Mouse Model of Glaucoma. Ann Biomed Eng 2021; 49:858-870. [PMID: 32974756 PMCID: PMC7854493 DOI: 10.1007/s10439-020-02608-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 09/02/2020] [Indexed: 12/19/2022]
Abstract
Glaucoma is a neurodegenerative disease in which the retinal ganglion cell axons of the optic nerve degenerate concomitant with synaptic changes in the retina, leading finally to death of the retinal ganglion cells (RGCs). Electrical stimulation has been used to improve neural regeneration in a variety of systems, including in diseases of the retina. Therefore, the focus of this study was to investigate whether transcorneal electrical stimulation (TES) in the DBA2/J mouse model of glaucoma could improve retinal or optic nerve pathology and serve as a minimally invasive treatment option. Mice (10 months-old) received 21 sessions of TES over 8 weeks, after which we evaluated RGC number, axon number, and anterograde axonal transport using histology and immunohistochemistry. To gain insight into the mechanism of proposed protection, we also evaluated inflammation by quantifying CD3+ T-cells and Iba1+ microglia; perturbations in metabolism were shown via the ratio pAMPK to AMPK, and changes in trophic support were tested using protein capillary electrophoresis. We found that TES resulted in RGC axon protection, a reduction in inflammatory cells and their activation, improved energy homeostasis, and a reduction of the cell death-associated p75NTR. Collectively, the data indicated that TES maintained axons, decreased inflammation, and increased trophic factor support, in the form of receptor presence and energy homeostasis, suggesting that electrical stimulation impacts several facets of the neurodegenerative process in glaucoma.
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Affiliation(s)
- Assraa Hassan Jassim
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA
- Department of Basic and Translational Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | - McKay Cavanaugh
- Department of Biomedical Engineering, University of Akron, Akron, OH, USA
| | | | - Rebecca Willits
- Department of Biomedical Engineering, University of Akron, Akron, OH, USA.
- Department of Chemical Engineering, Northeastern University, Boston, MA, USA.
| | - Denise M Inman
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH, USA.
- North Texas Eye Research Institute, UNT-HSC, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA.
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Astragalus membranaceus Injection Protects Retinal Ganglion Cells by Regulating the Nerve Growth Factor Signaling Pathway in Experimental Rat Traumatic Optic Neuropathy. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2020:2429843. [PMID: 33381196 PMCID: PMC7762646 DOI: 10.1155/2020/2429843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 12/01/2020] [Accepted: 12/07/2020] [Indexed: 02/07/2023]
Abstract
Activation of the nerve growth factor (NGF) signaling pathway is a potential method of treatment for retinal ganglion cell (RGC) loss due to traumatic optic neuropathy (TON). The present study aimed to explore the biological effects of injecting Astragalus membranaceus (A. mem) on RGCs in an experimental TON model. Adult male Wistar rats were randomly divided into three groups: sham-operated (SL), model (ML), and A. mem injection (AL). The left eyes of the rats were considered the experimental eyes, and the right eyes served as the controls. AL rats received daily intraperitoneal injections of A. mem (3 mL/kg), whereas ML and SL rats were administered the same volume of normal saline. The TON rat model was induced by optic nerve (ON) transverse quantitative traction. After two-week administration, the number of RGCs was determined using retrograde labeling with Fluoro-Gold. The protein levels of NGF, tyrosine kinase receptor A (TrkA), c-Jun N-terminal protein kinase (JNK), JNK phosphorylation (p-JNK), and nuclear factor kappa-B (NF-κB) were assessed using western blotting. The levels of p75 neurotrophin receptor (p75NTR) and NF-κB DNA binding were examined using real-time PCR and an electrophoretic mobility shift assay. In addition, the concentrations of JNK and p-JNK were assessed using an enzyme-linked immunosorbent assay. Results. The number of RGCs in ML was found to be significantly decreased (P < 0.01) relative to both AL and SL, together with the downregulation of NGF (P < 0.01), TrkA (P < 0.05), and NF-κB (P < 0.01); upregulation of p75NTR mRNA (P < 0.01); and increased protein levels of JNK (P < 0.05) and p-JNK (P < 0.05). Treatment using A. mem injection significantly preserved the density of RGCs in rats with experimental TON and markedly upregulated the proteins of NGF (P < 0.01), TrkA (P < 0.05), and NF-κB (P < 0.01) and downregulated the mRNA level of p75NTR(P < 0.01), as well as the proteins of JNK (P < 0.05) and p-JNK (P < 0.01). Thus, A. mem injection could reduce RGC death in TON induced by ON transverse quantitative traction by stimulating the NGF signaling pathway.
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de Campos VS, Calaza KC, Adesse D. Implications of TORCH Diseases in Retinal Development-Special Focus on Congenital Toxoplasmosis. Front Cell Infect Microbiol 2020; 10:585727. [PMID: 33194824 PMCID: PMC7649341 DOI: 10.3389/fcimb.2020.585727] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/09/2020] [Indexed: 12/15/2022] Open
Abstract
There are certain critical periods during pregnancy when the fetus is at high risk for exposure to teratogens. Some microorganisms, including Toxoplasma gondii, are known to exhibit teratogenic effects, interfering with fetal development and causing irreversible disturbances. T. gondii is an obligate intracellular parasite and the etiological agent of Toxoplasmosis, a zoonosis that affects one third of the world's population. Although congenital infection can cause severe fetal damage, the injury extension depends on the gestational period of infection, among other factors, like parasite genotype and host immunity. This parasite invades the Central Nervous System (CNS), forming tissue cysts, and can interfere with neurodevelopment, leading to frequent neurological abnormalities associated with T. gondii infection. Therefore, T. gondii is included in the TORCH complex of infectious diseases that may lead to neurological malformations (Toxoplasmosis, Others, Rubella, Cytomegalovirus, and Herpes). The retina is part of CNS, as it is derived from the diencephalon. Except for astrocytes and microglia, retinal cells originate from multipotent neural progenitors. After cell cycle exit, cells migrate to specific layers, undergo morphological and neurochemical differentiation, form synapses and establish their circuits. The retina is organized in nuclear layers intercalated by plexus, responsible for translating and preprocessing light stimuli and for sending this information to the brain visual nuclei for image perception. Ocular toxoplasmosis (OT) is a very debilitating condition and may present high severity in areas in which virulent strains are found. However, little is known about the effect of congenital infection on the biology of retinal progenitors/ immature cells and how this infection may affect the development of this tissue. In this context, this study reviews the effects that congenital infections may cause to the developing retina and the cellular and molecular aspects of these diseases, with special focus on congenital OT.
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Affiliation(s)
- Viviane Souza de Campos
- Laboratório de Neurobiologia da Retina, Instituto de Biologia, Universidade Federal Fluminense, Niteroi, Brazil
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Karin C. Calaza
- Laboratório de Neurobiologia da Retina, Instituto de Biologia, Universidade Federal Fluminense, Niteroi, Brazil
| | - Daniel Adesse
- Laboratório de Biologia Estrutural, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
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Nguyen-Ba-Charvet KT, Rebsam A. Neurogenesis and Specification of Retinal Ganglion Cells. Int J Mol Sci 2020; 21:ijms21020451. [PMID: 31936811 PMCID: PMC7014133 DOI: 10.3390/ijms21020451] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 01/07/2020] [Accepted: 01/08/2020] [Indexed: 12/25/2022] Open
Abstract
Across all species, retinal ganglion cells (RGCs) are the first retinal neurons generated during development, followed by the other retinal cell types. How are retinal progenitor cells (RPCs) able to produce these cell types in a specific and timely order? Here, we will review the different models of retinal neurogenesis proposed over the last decades as well as the extrinsic and intrinsic factors controlling it. We will then focus on the molecular mechanisms, especially the cascade of transcription factors that regulate, more specifically, RGC fate. We will also comment on the recent discovery that the ciliary marginal zone is a new stem cell niche in mice contributing to retinal neurogenesis, especially to the generation of ipsilateral RGCs. Furthermore, RGCs are composed of many different subtypes that are anatomically, physiologically, functionally, and molecularly defined. We will summarize the different classifications of RGC subtypes and will recapitulate the specification of some of them and describe how a genetic disease such as albinism affects neurogenesis, resulting in profound visual deficits.
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Mesentier-Louro LA, Rosso P, Carito V, Mendez-Otero R, Santiago MF, Rama P, Lambiase A, Tirassa P. Nerve Growth Factor Role on Retinal Ganglion Cell Survival and Axon Regrowth: Effects of Ocular Administration in Experimental Model of Optic Nerve Injury. Mol Neurobiol 2019; 56:1056-1069. [PMID: 29869196 DOI: 10.1007/s12035-018-1154-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/24/2018] [Indexed: 01/04/2023]
Abstract
Retinal ganglion cell (RGC) degeneration occurs within 2 weeks following optic nerve crush (ONC) as a consequence of reduced retro-transport of growth factors including nerve growth factor (NGF). The hypothesis that intravitreal (ivt) and eye drop (ed) administration of recombinant human NGF (rhNGF) might counteract ONC in adult rats is explored in this study. We found that both ivt- and ed-rhNGF reduced RGC loss and stimulated axonal regrowth. Chiefly, survival and regenerative effects of rhNGF were associated with a reduction of cells co-expressing Nogo-A/p75NTR at crush site borders, which contribute to glia scar formation following nerve injury, and induce further degeneration. We also found that ocular application of rhNGF reduced p75NTR and proNGF and enhanced phosphorylation of TrkA and its intracellular signals at retina level. Nogo-R and Rock2 expression was also normalized by ed-rhNGF treatment in both ONC and contralateral retina. Our findings that ocular applied NGF reaches and exerts biological actions on posterior segment of the eye give a further insight into the neurotrophin diffusion/transport through eye structures and/or their trafficking in optic nerve. In addition, the use of a highly purified NGF form in injury condition in which proNGF/p75NTR binding is favored indicates that increased availability of mature NGF restores the balance between TrkA and p75NGF, thus resulting in RGC survival and axonal growth. In conclusion, ocular applied NGF is confirmed as a good experimental paradigm to study mechanisms of neurodegeneration and regeneration, disclose biomarkers, and time windows for efficacy treatment following cell or nerve injury.
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Affiliation(s)
- Louise A Mesentier-Louro
- Eye Repair Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Pamela Rosso
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR), Via di Fosso di Fiorano, 64 (00143), Rome, Italy
| | - Valentina Carito
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR), Via di Fosso di Fiorano, 64 (00143), Rome, Italy
| | - Rosalia Mendez-Otero
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcelo F Santiago
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Paolo Rama
- Eye Repair Unit, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy
| | - Alessandro Lambiase
- Section of Ophthalmology, Department of Sense Organs, University Sapienza, Rome, Italy
| | - Paola Tirassa
- Institute of Cell Biology and Neurobiology (IBCN), National Research Council (CNR), Via di Fosso di Fiorano, 64 (00143), Rome, Italy.
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Brain-Derived Neurotrophin and TrkB in Head and Neck Squamous Cell Carcinoma. Int J Mol Sci 2019; 20:ijms20020272. [PMID: 30641914 PMCID: PMC6359060 DOI: 10.3390/ijms20020272] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 01/03/2019] [Accepted: 01/05/2019] [Indexed: 12/17/2022] Open
Abstract
We hypothesized that in head and neck squamous cell carcinoma (HNSCC), the neurotrophin brain-derived neurotrophic factor (BDNF) and its high affinity receptor TrkB regulate tumor cell survival, invasion, and therapy resistance. We used in situ hybridization for BDNF and immunohistochemistry (IHC) for TrkB in 131 HNSCC samples. Brain-derived neurotrophic factor was highly expressed in normal mucosa in HNSCC tissue and in cell lines, whereas only 42.74% of HNSCC tissue was TrkB+. One fourth of HNSCC cases was human papilloma virus (HPV)− positive, but the TrkB IHC frequency was not different in HPV-positive (HPV+) and negative cases. The UPCI-SCC090 cells expressed constitutive levels of TrkB. Transforming-growth-factor-β1 (1 ng/mL TGF-β1) induced TrkB in a subpopulation of SCC-25 cells. A single 10-µg/mL mitomycin C treatment in UPCI-SCC090 cells induced apoptosis and BDNF did not rescue them. The SCC-25 cells were resistant to the MMC treatment, and their growth decreased after TGF-β1 treatment, but was restored by BDNF if it followed TGF-β1. Taken together, BDNF might be ineffective in HPV+ HNSCC patients. In HPV− HNSCC patients, tumor cells did not die after chemotherapeutic challenge and BDNF with TGF-β1 could improve tumor cell survival and contribute to worse patient prognosis.
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Wang L, Yu C, Sun X, Chan SO. Dynamic expression of p75 NTR and Lingo-1 during development of mouse retinofugal pathway. Neurosci Lett 2018; 686:106-111. [PMID: 30201307 DOI: 10.1016/j.neulet.2018.09.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/30/2018] [Accepted: 09/06/2018] [Indexed: 10/28/2022]
Abstract
Our previous studies showed interaction of Nogo at the midline with its receptor (NgR) on optic axons plays a role in axon divergence at the mouse optic chiasm. Since NgR lacks a cytoplasmic domain, it needs transmembrane receptor partners for signal transduction. In this study, we examined whether the co-receptors of NgR, low-affinity neurotrophic receptor (p75NTR) and Lingo-1, are localized on axons in the mouse optic pathway. In the retina, p75NTR and Lingo-1 were observed on neuroepithelial cells at E13 and later on the retinal ganglion cells at E14 and E15. At the optic disc, p75NTR was observed on the retinal axons, whereas Lingo-1 was found on glial processes surrounding the axon fascicles. Both p75NTR and Lingo-1 were found on axons in the optic stalk, optic chiasm and optic tract. Furthermore, a transient expression of Lingo-1 was observed on the SSEA-1 positive chiasmatic neurons at E13, but not at later developmental stages. The presence of p75NTR and Lingo-1 on optic axons provides further supports to the contribution of Nogo/NgR signaling in axon divergence at the mouse optic chiasm.
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Affiliation(s)
- Liqing Wang
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China; School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
| | - Chao Yu
- Center of Health Examination, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China.
| | - Xiaobo Sun
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong, China.
| | - Sun-On Chan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, China.
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Chitranshi N, Dheer Y, Abbasi M, You Y, Graham SL, Gupta V. Glaucoma Pathogenesis and Neurotrophins: Focus on the Molecular and Genetic Basis for Therapeutic Prospects. Curr Neuropharmacol 2018; 16:1018-1035. [PMID: 29676228 PMCID: PMC6120108 DOI: 10.2174/1570159x16666180419121247] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 04/10/2018] [Accepted: 04/18/2018] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Retinal ganglion cell (RGC) degeneration is a major feature of glaucoma pathology. Neuroprotective approaches that delay or halt the progression of RGC loss are needed to prevent vision loss which can occur even after conventional medical or surgical treatments to lower intraocular pressure. OBJECTIVE The aim of this review was to examine the progress in genetics and cellular mechanisms associated with endoplasmic reticulum (ER) stress, RGC dysfunction and cell death pathways in glaucoma. MATERIALS AND METHODS Here, we review the involvement of neurotrophins like brain derived neurotrophic factor (BDNF) and its high affinity receptor tropomyosin receptor kinase (TrkB) in glaucoma. The role of ER stress markers in human and animal retinas in health and disease conditions is also discussed. Further, we analysed the literature highlighting genetic linkage in the context of primary open angle glaucoma and suggested mechanistic insights into potential therapeutic options relevant to glaucoma management. RESULTS The literature review of the neurobiology underlying neurotrophin pathways, ER stress and gene associations provide critical insights into association of RGCs death in glaucoma. Alteration in signalling pathway is associated with increased risk of misfolded protein aggregation in ER promoting RGC apoptosis. Several genes that are linked with neurotrophin signalling pathways have been reported to be associated with glaucoma pathology. CONCLUSION Understanding genetic heterogeneity and involvement of neurotrophin biology in glaucoma could help to understand the complex pathophysiology of glaucoma. Identification of novel molecular targets will be critical for drug development and provide neuroprotection to the RGCs and optic nerve.
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Affiliation(s)
- Nitin Chitranshi
- Address correspondence to this author at the Faculty of Medicine and Health Sciences, 75, Talavera Road, Macquarie University, Sydney, NSW 2109, Australia; Tel: +61-298502760; E-mail:
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Garcia TB, Hollborn M, Bringmann A. Expression and signaling of NGF in the healthy and injured retina. Cytokine Growth Factor Rev 2017; 34:43-57. [PMID: 27964967 DOI: 10.1016/j.cytogfr.2016.11.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 11/28/2016] [Indexed: 01/02/2023]
Abstract
This review summarizes the present knowledge concerning the retinal localization of the nerve growth factor (NGF), its precursor proNGF, and the receptors TrkA and p75NTR in the developing and mature rodent retina. We further discuss the changes in the expression of NGF and the receptors in experimental models of retinal disorders and diseases like inherited retinitis pigmentosa, retinal detachment, glaucoma, and diabetic retinopathy. Since proNGF is now recognized as a bioactive signaling molecule which induces cell death through p75NTR activation, the role of proNGF in the induction of retinal cell loss under neurodegenerative conditions is also highlighted. In addition, we present the evidences for a potential therapeutic intervention with NGF for the treatment of retinal neurodegenerative diseases. Different strategies have been developed and experimentally tested in mice and rats in order to reduce cell loss and Müller cell gliosis, e.g., increasing the availability of endogenous NGF, administration of exogenous NGF, activation of TrkA, and inhibition of p75NTR. Here, we discuss the several lines of evidence supporting a protective effect of NGF on retinal cell loss, with specific emphasis on photoreceptor and retinal ganglion cell degeneration. A better understanding of the mechanisms underlying the effects of NGF and proNGF in the modulation of neurodegeneration and gliosis in the retina will help to develop efficient therapeutic strategies for various retinal diseases.
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Affiliation(s)
| | - Margrit Hollborn
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
| | - Andreas Bringmann
- Department of Ophthalmology and Eye Hospital, University of Leipzig, Leipzig, Germany
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Time-Dependent Nerve Growth Factor Signaling Changes in the Rat Retina During Optic Nerve Crush-Induced Degeneration of Retinal Ganglion Cells. Int J Mol Sci 2017; 18:ijms18010098. [PMID: 28067793 PMCID: PMC5297732 DOI: 10.3390/ijms18010098] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 12/20/2016] [Accepted: 12/24/2016] [Indexed: 01/06/2023] Open
Abstract
Nerve growth factor (NGF) is suggested to be neuroprotective after nerve injury; however, retinal ganglion cells (RGC) degenerate following optic-nerve crush (ONC), even in the presence of increased levels of endogenous NGF. To further investigate this apparently paradoxical condition, a time-course study was performed to evaluate the effects of unilateral ONC on NGF expression and signaling in the adult retina. Visually evoked potential and immunofluorescence staining were used to assess axonal damage and RGC loss. The levels of NGF, proNGF, p75NTR, TrkA and GFAP and the activation of several intracellular pathways were analyzed at 1, 3, 7 and 14 days after crush (dac) by ELISA/Western Blot and PathScan intracellular signaling array. The progressive RGC loss and nerve impairment featured an early and sustained activation of apoptotic pathways; and GFAP and p75NTR enhancement. In contrast, ONC-induced reduction of TrkA, and increased proNGF were observed only at 7 and 14 dac. We propose that proNGF and p75NTR contribute to exacerbate retinal degeneration by further stimulating apoptosis during the second week after injury, and thus hamper the neuroprotective effect of the endogenous NGF. These findings might aid in identifying effective treatment windows for NGF-based strategies to counteract retinal and/or optic-nerve degeneration.
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Balzamino BO, Esposito G, Marino R, Keller F, Micera A. NGF Expression in Reelin-Deprived Retinal Cells: A Potential Neuroprotective Effect. Neuromolecular Med 2015; 17:314-25. [PMID: 26066836 DOI: 10.1007/s12017-015-8360-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 05/30/2015] [Indexed: 11/25/2022]
Abstract
We recently reported that increased NGF and p75(NTR) as well as decreased trkA(NGFR) characterized the Reelin-deprived (E-Reeler) retina, prospecting a potential contribution of NGF during E-Reeler retinogenesis. Herein, retinal ganglion cells (RGCs), glial cells and rod bipolar cells (RBCs) were isolated from E-Reeler retinas, and NGF, trkA(NGFR)/p75(NTR) expression and apoptosis were investigated. E-Reeler (n = 28) and E-control (n = 34) retinas were digested, and RGCs, glial cells and RBCs were isolated by the magnetic bead separation. Expression of NGF, trkA(NGFR), p75(NTR), Annexin V/PI and Bcl2/Bax was quantified by flow cytometry and validated by real-time PCR or WB. In E-Reeler retinas, NGF was significantly increased in RGCs and glial cells, p75(NTR) was increased in both RBCs and RGCs, and trkA(NGFR) was unchanged. In E-control retinas, NGF and p75(NTR) were expressed mainly in RBCs and RGCs and faintly in glial cells, while trkA(NGFR) was weakly expressed by RBCs and RGCs. In RBCs and RGCs, Annexin V expression was unchanged, while Bcl2 increased and Bax decreased selectively in E-Reeler RGCs. The data indicate that E-Reeler RBCs and RGCs overexpress NGF and p75(NTR) as a protective endogenous response to Reelin deprivation. The observation is strongly supported by the absence of apoptosis in both cell types.
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Affiliation(s)
- Bijorn Omar Balzamino
- Laboratory of Ophthalmology, Ocular Surface Unit, IRCCS-G.B. Bietti Foundation, via Alvaro del Portillo 21, 00128, Rome, Italy
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Imbalance of the nerve growth factor and its precursor as a potential biomarker for diabetic retinopathy. BIOMED RESEARCH INTERNATIONAL 2015; 2015:571456. [PMID: 25853140 PMCID: PMC4380101 DOI: 10.1155/2015/571456] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 10/08/2014] [Accepted: 10/08/2014] [Indexed: 02/07/2023]
Abstract
Our previous studies have demonstrated that diabetes-induced oxidative stress alters homeostasis of retinal nerve growth factor (NGF) resulting in accumulation of its precursor, proNGF, at the expense of NGF which plays a critical role in preserving neuronal and retinal function. This imbalance coincided with retinal damage in experimental diabetes. Here we test the hypothesis that alteration of proNGF and NGF levels observed in retina and vitreous will be mirrored in serum of diabetic patients. Blood and vitreous samples were collected from patients (diabetic and nondiabetic) undergoing vitrectomy at Georgia Regents University under approved IRB. Levels of proNGF, NGF, and p75NTR shedding were detected using Western blot analysis. MMP-7 activity was also assayed. Diabetes-induced proNGF expression and impaired NGF expression were observed in vitreous and serum. Vitreous and sera from diabetic patients (n = 11) showed significant 40.8-fold and 3.6-fold increases, respectively, compared to nondiabetics (n = 9). In contrast, vitreous and sera from diabetic patients showed significant 44% and 64% reductions in NGF levels, respectively, compared to nondiabetics. ProNGF to NGF ratios showed significant correlation between vitreous and serum. Further characterization of diabetes-induced imbalance in the proNGF to NGF ratio will facilitate its utility as an early biomarker for diabetic complications.
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Mii S, Amoh Y, Katsuoka K, Hoffman RM. Comparison of nestin-expressing multipotent stem cells in the tongue fungiform papilla and vibrissa hair follicle. J Cell Biochem 2014; 115:1070-6. [PMID: 24142339 DOI: 10.1002/jcb.24696] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 10/14/2013] [Indexed: 11/10/2022]
Abstract
We have previously reported that hair follicles contain multipotent stem cells, which express nestin and participate in follicle growth at anagen as well as in the extension of the follicle sensory nerve. The nestin-driven green fluorescent protein (ND-GFP) transgenic mouse labels all nestin-expressing cells with GFP. The hair follicle nestin-GFP cells can differentiate into neurons, Schwann cells, and other cell types. In this study, we describe nestin-expressing multipotent stem cells in the fungiform papilla in the tongue. The nestin-expressing multipotent stem cells in the fungiform papilla are located around a peripheral sensory nerve immediately below the taste bud and co-express the neural crest cell marker p75(NTR) . The fungiform papilla cells formed spheres in suspension culture in DMEM-F12 medium supplemented with basic fibroblast growth factor (bFGF). The spheres consisted of nestin-expressing cells that co-expressed the neural crest marker p75(NTR) and which developed expression of the stem cell marker CD34. P75(NTR), CD34 and nestin co-expression suggested that nestin-expressing cells comprising the fungiform papilla spheres were in a relatively undifferentiated state. The nestin-expressing cells of these spheres acquired the following markers: β III tubulin typical of nerve cells; GFAP typical of glial cells; K15 typical of keratinocytes; and smooth-muscle antigen (SMA), after transfer to RPMI 1640 medium with 10% fetal bovine serum (FBS), suggesting they differentiated into multiple cell types. The results of the current study indicate nestin-expressing fungiform papilla cells and the nestin-expressing hair follicle stem cells have common features of cell morphology and ability to differentiate into multiple cell types, suggesting their remarkable similarity.
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Affiliation(s)
- Sumiyuki Mii
- AntiCancer, Inc., San Diego, California, 92111; Department of Surgery, University of California, San Diego, California, 92103-8220; Department of Dermatology, Kitasato University School of Medicine, Kanagawa, 252-0374, Japan
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Mysona BA, Shanab AY, Elshaer SL, El-Remessy AB. Nerve growth factor in diabetic retinopathy: beyond neurons. EXPERT REVIEW OF OPHTHALMOLOGY 2014; 9:99-107. [PMID: 25031607 PMCID: PMC4096131 DOI: 10.1586/17469899.2014.903157] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Diabetic retinopathy (DR), a major ocular complication of diabetes, is a leading cause of blindness in US working age adults with limited treatments. Neurotrophins (NTs), a family of proteins essential for growth, differentiation and survival of retinal neurons, have emerged as potential players in the pathogenesis of DR. NTs can signal through their corresponding tropomyosin kinase related receptor to mediate cell survival or through the p75 neurotrophin receptor with the co-receptor, sortilin, to mediate cell death. This review focuses on the role of NGF, the first discovered NT, in the development of DR. Impaired processing of proNGF has been found in ocular fluids from diabetic patients as well as experimental models. Evidence from literature and our studies support the notion that NTs appear to play multiple potential roles in DR, hence, understanding their contribution to DR may lead to promising therapeutic approaches for this devastating disease.
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Affiliation(s)
- Barbara A Mysona
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, USA and Culver Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA and Charlie Norwood Veterans Affairs Medical Center, Augusta, GA, USA
| | - Ahmed Y Shanab
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, USA and Culver Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA and Charlie Norwood Veterans Affairs Medical Center, Augusta, GA, USA
| | - Sally L Elshaer
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, USA and Culver Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA and Charlie Norwood Veterans Affairs Medical Center, Augusta, GA, USA
| | - Azza B El-Remessy
- Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, USA and Culver Vision Discovery Institute, Georgia Regents University, Augusta, GA, USA and Charlie Norwood Veterans Affairs Medical Center, Augusta, GA, USA
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15
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Jia YX, Li JR, Mao CY, Yin WT, Jiang RH. Glycyrrhizin improves p75NTR-associated sciatic nerve regeneration in a BALB/c mouse model. Exp Ther Med 2014; 7:1141-1146. [PMID: 24940400 PMCID: PMC3991491 DOI: 10.3892/etm.2014.1546] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 02/10/2014] [Indexed: 12/22/2022] Open
Abstract
Glycyrrhizin has a role in immune regulation in the central nervous system, but its impact on sciatic nerve injury had not previously been reported. In this study, a BALB/c mouse model of sciatic nerve injury was used to explore the role of glycyrrhizin in sciatic nerve repair and its underlying mechanism. Glycyrrhizin with intragastric gavage of 10 and 20 mg/kg weight per day (mid- and high-dose, respectively) inhibited p75 neurotrophin receptor (p75NTR) expression at the protein and mRNA levels versus the 5 mg/kg (low-dose) group and control (0.9% NaCl solution) at one, two, four and eight weeks following sciatic nerve injury, and simultaneously improved the action potential amplitude and motor nerve conductive velocity. Combined Marsland, Glees and Erikson’s silver stain and Luxol fast blue staining results indicated that high- and mid-dose glycyrrhizin promoted improved sciatic nerve myelination compared with the low-dose or control groups eight weeks after injury. Immunofluorescence staining demonstrated that glycyrrhizin had an inhibitory effect to a certain degree on local hypertrophic scar and inflammatory responses in the mouse model. In conclusion, glycyrrhizin can promote sciatic nerve regeneration and functional repair, in which doses of 10 and 20 mg/kg per day are more effective than lower doses, and such regeneration is associated with the downregulation of p75NTR.
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Affiliation(s)
- Yu-Xi Jia
- Department of Orthopaedics, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Jin-Ran Li
- Jilin University Bethune School of Medical Sciences, Changchun, Jilin 130021, P.R. China
| | - Cui-Ying Mao
- Department of Orthopaedics, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Wei-Tian Yin
- Department of Orthopaedics, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
| | - Ri-Hua Jiang
- Department of Dermatology, China-Japan Union Hospital of Jilin University, Changchun, Jilin 130033, P.R. China
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Characterization of NGF, trkA (NGFR) , and p75 (NTR) in Retina of Mice Lacking Reelin Glycoprotein. Int J Cell Biol 2014; 2014:725928. [PMID: 24627687 PMCID: PMC3928862 DOI: 10.1155/2014/725928] [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: 10/11/2013] [Accepted: 11/04/2013] [Indexed: 12/31/2022] Open
Abstract
Both Reelin and Nerve Growth Factor (NGF) exert crucial roles in retinal development. Retinogenesis is severely impaired in E-reeler mice, a model of Reelin deficiency showing specific Green Fluorescent Protein expression in Rod Bipolar Cells (RBCs). Since no data are available on Reelin and NGF cross-talk, NGF and trkANGFR/ p75NTR expression was investigated in retinas from E-reeler versus control mice, by confocal microscopy, Western blotting, and real time PCR analysis. A scattered increase of NGF protein was observed in the Ganglion Cell Layer and more pronounced in the Inner Nuclear Layer (INL). A selective increase of p75NTR was detected in most of RBCs and in other cell subtypes of INL. On the contrary, a slight trend towards a decrease was detected for trkANGFR, albeit not significant. Confocal data were validated by Western blot and real time PCR. Finally, the decreased trkANGFR/ p75NTR ratio, representative of p75NTR increase, significantly correlated with E-reeler versus E-control. These data indicate that NGF-trkANGFR/ p75NTR is affected in E-reeler retina and that p75NTR might represent the main NGF receptor involved in the process. This first NGF-trkANGFR/ p75NTR characterization suggests that E-reeler might be suitable for exploring Reelin-NGF cross-talk, representing an additional information source in those pathologies characterized by retinal degeneration.
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Kelberman D, Islam L, Lakowski J, Bacchelli C, Chanudet E, Lescai F, Patel A, Stupka E, Buck A, Wolf S, Beales PL, Jacques TS, Bitner-Glindzicz M, Liasis A, Lehmann OJ, Kohlhase J, Nischal KK, Sowden JC. Mutation of SALL2 causes recessive ocular coloboma in humans and mice. Hum Mol Genet 2014; 23:2511-26. [PMID: 24412933 PMCID: PMC3990155 DOI: 10.1093/hmg/ddt643] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Ocular coloboma is a congenital defect resulting from failure of normal closure of the optic fissure during embryonic eye development. This birth defect causes childhood blindness worldwide, yet the genetic etiology is poorly understood. Here, we identified a novel homozygous mutation in the SALL2 gene in members of a consanguineous family affected with non-syndromic ocular coloboma variably affecting the iris and retina. This mutation, c.85G>T, introduces a premature termination codon (p.Glu29*) predicted to truncate the SALL2 protein so that it lacks three clusters of zinc-finger motifs that are essential for DNA-binding activity. This discovery identifies SALL2 as the third member of the Drosophila homeotic Spalt-like family of developmental transcription factor genes implicated in human disease. SALL2 is expressed in the developing human retina at the time of, and subsequent to, optic fissure closure. Analysis of Sall2-deficient mouse embryos revealed delayed apposition of the optic fissure margins and the persistence of an anterior retinal coloboma phenotype after birth. Sall2-deficient embryos displayed correct posterior closure toward the optic nerve head, and upon contact of the fissure margins, dissolution of the basal lamina occurred and PAX2, known to be critical for this process, was expressed normally. Anterior closure was disrupted with the fissure margins failing to meet, or in some cases misaligning leading to a retinal lesion. These observations demonstrate, for the first time, a role for SALL2 in eye morphogenesis and that loss of function of the gene causes ocular coloboma in humans and mice.
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Braunger BM, Demmer C, Tamm ER. Programmed cell death during retinal development of the mouse eye. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:9-13. [PMID: 24664675 DOI: 10.1007/978-1-4614-3209-8_2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Similar to other parts of the central nervous system, there are two types of programmed cell death during retinal development. In early development, the neuronal progenitor population is affected. In the mouse eye, this kind of programmed cell death begins at around embryonic day (E) 12.5 and peaks between E14.5 and E16.5. The second phase of programmed cell death occurs during synaptogenesis within the first 2 postnatal weeks. Important signaling mechanisms that induce programmed cell death of retinal progenitors appear to involve nerve growth factor acting on the proapoptotic receptor to p75 neurotrophin receptor (p75(NTR)) and transforming growth factor-β.
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Affiliation(s)
- Barbara M Braunger
- Institute of Human Anatomy and Embryology, University of Regensburg, Universitätsstr. 31, 93053, Regensburg, Germany
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TGF-β signaling protects retinal neurons from programmed cell death during the development of the mammalian eye. J Neurosci 2013; 33:14246-58. [PMID: 23986258 DOI: 10.1523/jneurosci.0991-13.2013] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We investigated the influence of transforming growth factor-β (TGF-β) signaling on developmental programmed cell death in the mouse retina by direct and specific molecular targeting of TGF-β type II receptor (TβRII) and Smad7 in retinal progenitor cells. Mice were generated carrying a conditional deletion of the TβRII in cells that originate from the inner layer of the optic cup. The animals showed a significant decrease of phosphorylated Smad3 in both the central and peripheral retina, which indicates the diminished activity of TGF-β signaling. TβRII deficiency significantly increased the apoptotic death of retinal neurons during embryonic and postnatal development without affecting their proliferation. In contrast, treatment with TGF-β2 inhibited cell death of retinal ganglion cells in dissociated retinal cell cultures, an effect that was blocked by inhibiting the phosphorylation of Smad3. The increase in apoptosis during development resulted in a significant reduction in the number of neurons in adult TβRII-deficient mice. The effect was most pronounced in the inner retina neurons and resulted in functional deficits as determined by electroretinography. In contrast, a conditional deletion of TGF-β-inhibiting Smad7 in retinal neurons significantly enhanced Smad3 phosphorylation and significantly decreased apoptosis of retinal neurons in embryos and pups. Moreover, the number of retinal ganglion cells was significantly higher in Smad7-deficient mice compared with control littermates. TβRII-deficient pups showed a lower level of nerve growth factor (NGF) in its mRNA; however, higher levels were observed in Smad7-deficient pups, which strongly suggests that the protective effects of TGF-β signaling on developmental cell death are mediated through NGF.
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Neuronal programmed cell death-1 ligand expression regulates retinal ganglion cell number in neonatal and adult mice. J Neuroophthalmol 2013; 32:227-37. [PMID: 22635166 DOI: 10.1097/wno.0b013e3182589589] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVES During mouse retina maturation, the final number of retinal ganglion cells (RGCs) is determined by highly regulated programmed cell death. Previous studies demonstrated that the immunoregulatory receptor programmed cell death-1 (PD-1) promotes developmental RGC death. To identify the functional signaling partner(s) for PD-1, we identified retinal expression of PD-1 ligands and examined the effect of PD-1 ligand expression on RGC number. We also explored the hypothesis that PD-1 signaling promotes the development of functional visual circuitry. METHODS Characterization of retinal and brain programmed cell death-1 ligand 1 (PD-L1) expression were examined by immunofluorescence on tissue sections. The contribution of PD-ligands, PD-L1, and programmed cell death-1 ligand 2 (PD-L2) to RGC number was examined in PD-ligand knockout mice lacking 1 or both ligands. Retinal architecture was assessed by spectral-domain optical coherence tomography, and retinal function was analyzed by electroretinography in wild-type and PD-L1/L2 double-deficient mice. RESULTS PD-L1 expression is found throughout the neonatal retina and persists in adult RGCs, bipolar interneurons, and Müller glia. In the absence of both PD-ligands, there is a significant numerical increase in RGCs (34% at postnatal day 2 [P2] and 18% in adult), as compared to wild type, and PD-ligands have redundant function in this process. Despite the increased RGC number, adult PD-L1/L2 double-knockout mice have normal retinal architecture and outer retina function. CONCLUSION This study demonstrates that PD-L1 and PD-L2 together impact the final number of RGCs in adult mice and supports a novel role for active promotion of neuronal cell death through PD-1 receptor-ligand engagement.
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21
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The molecular basis of retinal ganglion cell death in glaucoma. Prog Retin Eye Res 2012; 31:152-81. [DOI: 10.1016/j.preteyeres.2011.11.002] [Citation(s) in RCA: 565] [Impact Index Per Article: 47.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 10/28/2011] [Accepted: 11/01/2011] [Indexed: 12/14/2022]
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Harder JM, Libby RT. BBC3 (PUMA) regulates developmental apoptosis but not axonal injury induced death in the retina. Mol Neurodegener 2011; 6:50. [PMID: 21762490 PMCID: PMC3149592 DOI: 10.1186/1750-1326-6-50] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 07/15/2011] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Naturally occurring apoptosis is a developmental process that shapes the retina by eliminating overproduced neurons. In the absence of the proapoptotic Bcl-2 family member BAX, developmental apoptosis in the retina is disrupted and extra neurons survive. It is unknown how BAX is activated or if this regulation varies between neuronal types and subtypes. Since the Bcl-2 family members BIM, BID, and BBC3 (PUMA) are powerful direct activators of BAX, we used mice deficient for each of these genes to investigate their importance in developmental apoptosis. RESULTS Bax deficient mice have an increase in retinal ganglion cells (RGCs), bipolar cells and dopaminergic amacrine cells, but not photoreceptors, horizontal cells or cholinergic amacrine cells. The retinas of adult Bim and Bid deficient mice appeared to have no increase in any retinal cell type. Bbc3 deficient mice, either homozygous or heterozygous for a null allele of Bbc3, had an increase in the same cell types as Bax deficient mice. An analogous result may occur in the brain where, similar to Bax deficient mice, Bbc3 deficient mice have a larger gross brain weight compared to wild type mice. In contrast to its developmental role, BBC3 did not appear to be a primary factor in BAX-dependent axonal injury induced neurodegeneration in adult RGCs. CONCLUSION The regulation of BAX activation in the retina appears to be complex, dependent on the developmental stage of the animal, the nature of the insult and even the type of neuron.
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Affiliation(s)
- Jeffrey M Harder
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, NY, USA.
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23
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Frade JM. Somatic tetraploidy in vertebrate neurons: Implications in physiology and pathology. Commun Integr Biol 2011; 3:201-3. [PMID: 20585523 DOI: 10.4161/cib.3.2.11061] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Accepted: 12/28/2009] [Indexed: 11/19/2022] Open
Abstract
The presence of polyploid neurons in the vertebrate nervous system has been a subject of debate since the 1960s. At that time, Purkinje cells were proposed to be tetraploid, but technical limitations impeded to reach a clear conclusion, and the current belief is that most vertebrate neurons are diploid. By using up-to-date approaches we have recently demonstrated the existence of a subpopulation of tetraploid retinal ganglion cells (RGCs) in the vertebrate retina. In the chick, these neurons show large somas and extensive dendritic trees and most of them express a marker specific for RGCs innervating a specific lamina of the optic tectum. We have also demonstrated that these neurons are generated in response to nerve growth factor (NGF) acting through the neurotrophin receptor p75 (p75(NTR)), which induces E2F1 activity and cell cycle re-entry in migrating RGC neuroblasts lacking retinoblastoma (Rb) protein. We have also showed that brain-derived neurotrophic factor (BDNF) prevents G(2)/M transition in the tetraploid RGCs, thus being crucial for the maintenance of the tetraploid status as well as the survival of these neurons. The realization that tetraploid neurons can be readily observed in the vertebrate nervous system has important physiological consequences, which are discussed in this commentary.
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Affiliation(s)
- José María Frade
- Instituto Cajal; Consejo Superior de Investigaciones Científicas; Madrid, Spain
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24
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TRPV1 receptors modulate retinal development. Int J Dev Neurosci 2011; 29:405-13. [PMID: 21414401 DOI: 10.1016/j.ijdevneu.2011.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Revised: 01/19/2011] [Accepted: 03/08/2011] [Indexed: 12/11/2022] Open
Abstract
We investigated the possible participation of TRPV1 channels in retinal apoptosis and overall development. Retinas from newborn, male albino rats were treated in vitro with capsazepine, a TRPV1 antagonist. The expression of cell cycle markers was not changed after TRPV1 blockade, whereas capsazepine reduced the number of apoptotic cells throughout the retina,increased ERK1/2 and p38 phosphorylation and slightly reduced JNK phosphorylation. The expression of BAD, Bcl-2, as well as integral and cleaved capsase-3 were similar in all experimental conditions. Newborn rats were kept for 2 months after receiving high doses of capsazepine. In their retinas, calbindin and parvalbumin protein levels were upregulated, but only the number of amacrine-like, parvalbumin-positive cells was increased. The numbers of calretinin, calbindin, ChAT, vimentin, PKC-alpha and GABA-positive cells were similar in both conditions. Protein expression of synapsin Ib was also increased in the retinas of capsazepine-treated rats. Calretinin, vimentin, GFAP, synapsin Ia, synaptophysin and light neurofilament protein levels were not changed when compared to control values. Our results indicate that TRPV1 channels play a role in the control of the early apoptosis that occur during retinal development, which might be dependent on MAPK signaling. Moreover, it seems that TRPV1 function might be important for neuronal and synaptic maturation in the retina.
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Abstract
Somatic tetraploid neurons are present in different structures of the vertebrate nervous system, including cortex and retina. In this chapter, we provide evidence that these neurons can be widely detected in the chick nervous system. We also discuss mechanisms creating neuronal tetraploidy in vertebrates, concluding that the neurotrophin receptor p75 could be responsible for the generation of these neurons in most neural tissues, as previously observed in the retina. Somatic tetraploidy in the chick retina correlates with increased neurons' soma size and dendritic arborization, giving rise to neurons known to innervate a specific layer of the optic tectum. Tetraploidy could therefore account for neuronal diversity in the normal nervous system. De novo generation of tetraploid neurons has been shown to occur in Alzheimer's disease. This suggests that the morphological changes expected to occur in the affected neurons could lead to altered neuronal function, thus providing a basis for neurodegeneration.
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Yoshida T, Guo X, Namekata K, Mitamura Y, Kume S, Harada T. Expression of Epiplakin1 in the developing and adult mouse retina. Jpn J Ophthalmol 2010; 54:85-8. [DOI: 10.1007/s10384-009-0751-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 08/31/2009] [Indexed: 11/30/2022]
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ProNGF induces TNFalpha-dependent death of retinal ganglion cells through a p75NTR non-cell-autonomous signaling pathway. Proc Natl Acad Sci U S A 2010; 107:3817-22. [PMID: 20133718 DOI: 10.1073/pnas.0909276107] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neurotrophin binding to the p75 neurotrophin receptor (p75(NTR)) activates neuronal apoptosis following adult central nervous system injury, but the underlying cellular mechanisms remain poorly defined. In this study, we show that the proform of nerve growth factor (proNGF) induces death of retinal ganglion cells in adult rodents via a p75(NTR)-dependent signaling mechanism. Expression of p75(NTR) in the adult retina is confined to Müller glial cells; therefore we tested the hypothesis that proNGF activates a non-cell-autonomous signaling pathway to induce retinal ganglion cell (RGC) death. Consistent with this, we show that proNGF induced robust expression of tumor necrosis factor alpha (TNFalpha) in Müller cells and that genetic or biochemical ablation of TNFalpha blocked proNGF-induced death of retinal neurons. Mice rendered null for p75(NTR), its coreceptor sortilin, or the adaptor protein NRAGE were defective in proNGF-induced glial TNFalpha production and did not undergo proNGF-induced retinal ganglion cell death. We conclude that proNGF activates a non-cell-autonomous signaling pathway that causes TNFalpha-dependent death of retinal neurons in vivo.
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Hu Y, Cho S, Goldberg JL. Neurotrophic effect of a novel TrkB agonist on retinal ganglion cells. Invest Ophthalmol Vis Sci 2009; 51:1747-54. [PMID: 19875669 DOI: 10.1167/iovs.09-4450] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
PURPOSE Retinal ganglion cells (RGCs) die in glaucoma and virtually all optic neuropathies. Recently, novel tropomyosin-related kinase B (TrkB) monoclonal antibodies have been shown to activate TrkB receptors and exert neuroprotective and neurotrophic effects. In the present study, the authors examined the ability of one of them, 29D7, to elicit RGC survival and neurite growth both in culture and in vivo. METHODS RGCs from postnatal day (P)3 to P4 Sprague-Dawley rats were isolated by sequential immunopanning using a monoclonal antibody to Thy1. RGCs were cultured in serum-free defined medium in 96-well plates. RGC viability was assessed after 1 to 3 days by MTT assay. Activation of TrkB and downstream signaling molecules was confirmed by Western blot analysis. Intravitreal injections of 29D7 were performed after optic nerve axotomy, and subsequent RGC survival was quantified using beta-III tubulin immunostaining. Regeneration was assessed using retrograde fluorogold tracing in an optic nerve-peripheral nerve graft model. RESULTS Similar to brain-derived neurotrophic factor (BDNF), the 29D7 antibody strongly promoted RGC survival and neurite growth in vitro compared with medium alone or control IgG. Forskolin, which weakly supported RGC survival on its own, potentiated the effect of 29D7. Intravitreal injection of 29D7 enhanced RGC survival but not regeneration in vivo 2 weeks after optic nerve injury. CONCLUSIONS Together, these findings demonstrate the potential for antibody-mediated TrkB agonism as a potential therapeutic approach to enhance RGC survival after optic nerve injury. Further studies are needed to elucidate the mechanistic differences between this TrkB agonist and BDNF.
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Affiliation(s)
- Ying Hu
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, USA
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Kim T, Hempstead BL. NRH2 is a trafficking switch to regulate sortilin localization and permit proneurotrophin-induced cell death. EMBO J 2009; 28:1612-23. [PMID: 19407813 DOI: 10.1038/emboj.2009.118] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2008] [Accepted: 03/30/2009] [Indexed: 12/25/2022] Open
Abstract
Proneurotrophins mediate neuronal apoptosis using a dual receptor complex of sortilin and p75(NTR). Although p75(NTR) is highly expressed on the plasma membrane and accessible to proneurotrophin ligands, sortilin is primarily localized to intracellular membranes, limiting the formation of a cell surface co-receptor complex. Here, we show that the mammalian p75(NTR) homologue NRH2 critically regulates the expression of sortilin on the neuronal cell surface and promotes p75(NTR) and sortilin receptor complex formation, rendering cells responsive to proneurotrophins. This is accomplished by interactions between the cytoplasmic domains of NRH2 and sortilin that impair lysosomal degradation of sortilin. In proneurotrophin-responsive neurons, acute silencing of endogenous NRH2 significantly reduces cell surface-expressed sortilin and abolishes proneurotrophin-induced neuronal death. Thus, these data suggest that NRH2 acts as a trafficking switch to impair lysosomal-dependant sortilin degradation and to redistribute sortilin to the cell surface, rendering p75(NTR)-expressing cells susceptible to proneurotrophin-induced death.
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Affiliation(s)
- Taeho Kim
- Graduate Program in Neuroscience, Weill Medical College of Cornell University, New York, NY 10065, USA
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Inhibition of p75NTR in glia potentiates TrkA-mediated survival of injured retinal ganglion cells. Mol Cell Neurosci 2009; 40:410-20. [DOI: 10.1016/j.mcn.2008.12.005] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 10/09/2008] [Accepted: 12/02/2008] [Indexed: 12/21/2022] Open
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Lim YS, McLaughlin T, Sung TC, Santiago A, Lee KF, O'Leary DDM. p75(NTR) mediates ephrin-A reverse signaling required for axon repulsion and mapping. Neuron 2008; 59:746-58. [PMID: 18786358 DOI: 10.1016/j.neuron.2008.07.032] [Citation(s) in RCA: 157] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 03/07/2008] [Accepted: 07/21/2008] [Indexed: 01/08/2023]
Abstract
Reverse signaling by ephrin-As upon binding EphAs controls axon guidance and mapping. Ephrin-As are GPI-anchored to the membrane, requiring that they complex with transmembrane proteins that transduce their signals. We show that the p75 neurotrophin receptor (NTR) serves this role in retinal axons. p75(NTR) and ephrin-A colocalize within caveolae along retinal axons and form a complex required for Fyn phosphorylation upon binding EphAs, activating a signaling pathway leading to cytoskeletal changes. In vitro, retinal axon repulsion to EphAs by ephrin-A reverse signaling requires p75(NTR), but repulsion to ephrin-As by EphA forward signaling does not. Constitutive and retina-specific p75(NTR) knockout mice have aberrant anterior shifts in retinal axon terminations in superior colliculus, consistent with diminished repellent activity mediated by graded ephrin-A reverse signaling induced by graded collicular EphAs. We conclude that p75(NTR) is a signaling partner for ephrin-As and the ephrin-A- p75(NTR) complex reverse signals to mediate axon repulsion required for guidance and mapping.
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Affiliation(s)
- Yoo-Shick Lim
- Molecular Neurobiology Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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Abstract
More than half of the initially-formed neurons are deleted in certain brain regions during normal development. This process, whereby cells are discretely removed without interfering with the further development of remaining cells, is called programmed cell death (PCD). The term apoptosis is used to describe certain morphological manifestations of PCD. Many of the effectors of this developmental cell death program are highly expressed in the developing brain, making it more susceptible to accidental activation of the death machinery, e.g. following hypoxia-ischemia or irradiation. Recent evidence suggests, however, that activation and regulation of cell death mechanisms under pathological conditions do not exactly mirror physiological, developmentally regulated PCD. It may be argued that the conditions after e.g. ischemia are not even compatible with the execution of PCD as we know it. Under pathological conditions cells are exposed to various stressors, including energy failure, oxidative stress and unbalanced ion fluxes. This results in parallel triggering and potential overshooting of several different cell death pathways, which then interact with one another and result in complex patterns of biochemical manifestations and cellular morphological features. These types of cell death are here called "pathological apoptosis," where classical hallmarks of PCD, like pyknosis, nuclear condensation and caspase-3 activation, are combined with non-PCD features of cell death. Here we review our current knowledge of the mechanisms involved, with special focus on the potential for therapeutic intervention tailored to the needs of the developing brain.
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Affiliation(s)
- Klas Blomgren
- Center for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, Göteborg University, SE 405 30 Göteborg, Sweden.
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Jansen P, Giehl K, Nyengaard JR, Teng K, Lioubinski O, Sjoegaard SS, Breiderhoff T, Gotthardt M, Lin F, Eilers A, Petersen CM, Lewin GR, Hempstead BL, Willnow TE, Nykjaer A. Roles for the pro-neurotrophin receptor sortilin in neuronal development, aging and brain injury. Nat Neurosci 2007; 10:1449-57. [PMID: 17934455 DOI: 10.1038/nn2000] [Citation(s) in RCA: 214] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Accepted: 09/24/2007] [Indexed: 01/16/2023]
Abstract
Neurotrophins are essential for development and maintenance of the vertebrate nervous system. Paradoxically, although mature neurotrophins promote neuronal survival by binding to tropomyosin receptor kinases and p75 neurotrophin receptor (p75(NTR)), pro-neurotrophins induce apoptosis in cultured neurons by engaging sortilin and p75(NTR) in a death-signaling receptor complex. Substantial amounts of neurotrophins are secreted in pro-form in vivo, yet their physiological significance remains unclear. We generated a sortilin-deficient mouse to examine the contribution of the p75(NTR)/sortilin receptor complex to neuronal viability. In the developing retina, Sortilin 1 (Sort1)(-/-) mice showed reduced neuronal apoptosis that was indistinguishable from that observed in p75(NTR)-deficient (Ngfr(-/-)) mice. To our surprise, although sortilin deficiency did not affect developmentally regulated apoptosis of sympathetic neurons, it did prevent their age-dependent degeneration. Furthermore, in an injury protocol, lesioned corticospinal neurons in Sort1(-/-) mice were protected from death. Thus, the sortilin pathway has distinct roles in pro-neurotrophin-induced apoptotic signaling in pathological conditions, but also in specific stages of neuronal development and aging.
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Affiliation(s)
- Pernille Jansen
- MIND Center, Department of Medical Biochemistry, Ole Worms Allé 1170, Aarhus University, DK-8000 Aarhus C, Denmark
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Nakamura K, Namekata K, Harada C, Harada T. Intracellular sortilin expression pattern regulates proNGF-induced naturally occurring cell death during development. Cell Death Differ 2007; 14:1552-4. [PMID: 17541425 DOI: 10.1038/sj.cdd.4402173] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Bhargava S. Role of nerve growth factor and its receptor in the morphogenesis of neural tube in early chick embryo. Gen Comp Endocrinol 2007; 153:141-6. [PMID: 17418844 DOI: 10.1016/j.ygcen.2007.02.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 02/22/2007] [Accepted: 02/24/2007] [Indexed: 12/11/2022]
Abstract
Expression of p75 nerve growth factor receptor (p75(NTR)) in the early neurogenesis of chick embryo showed that nerve growth factor receptor (NGFR) is localized in presumptive neuroectoblast and endoblast in the chick gastrula but not in the mesoblast. By stages 9, 10, and 11, NGFR positive cells were located distinctly in the region where the neural folds converge, meet and fuse. NGFR expression was also seen in developing notochord and somites, wherein the reaction was localized on the cell surfaces. Strong p75(NTR) reaction was seen on the roof of the neural tube where it detaches from the head ectoderm by stage 12. The study revealed that p75(NTR) is co-expressed with NGF in the same developmental stage(s) and in areas, where cell death occurs during neuronal development. Further, when the endogenous levels of NGF signaling were blocked by anti-NGF antibody, abnormalities were observed at the anterior end of the neural tube formation. As a result, embryos showed open neural tubes and a few were bent on one side of the body axis. In a small proportion of embryos, diffused somites were observed. The findings supports and confirms our previous study that NGF signaling plays a significant role in the shaping of neural tube in chick embryos through p75(NTR)-NGF receptor.
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Affiliation(s)
- Shobha Bhargava
- Molecular Embryology Laboratory, Department of Zoology, University of Pune, Pune 411 007, India.
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36
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Harada T, Harada C, Parada LF. Molecular regulation of visual system development: more than meets the eye. Genes Dev 2007; 21:367-78. [PMID: 17322396 DOI: 10.1101/gad.1504307] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Vertebrate eye development has been an excellent model system to investigate basic concepts of developmental biology ranging from mechanisms of tissue induction to the complex patterning and bidimensional orientation of the highly specialized retina. Recent advances have shed light on the interplay between numerous transcriptional networks and growth factors that are involved in the specific stages of retinogenesis, optic nerve formation, and topographic mapping. In this review, we summarize this recent progress on the molecular mechanisms underlying the development of the eye, visual system, and embryonic tumors that arise in the optic system.
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Affiliation(s)
- Takayuki Harada
- Department of Developmental Biology, Kent Waldrep Foundation Center for Basic Neuroscience Research on Nerve Growth and Regeneration, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA
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Taylor AR, Gifondorwa DJ, Newbern JM, Robinson MB, Strupe JL, Prevette D, Oppenheim RW, Milligan CE. Astrocyte and muscle-derived secreted factors differentially regulate motoneuron survival. J Neurosci 2007; 27:634-44. [PMID: 17234595 PMCID: PMC6672790 DOI: 10.1523/jneurosci.4947-06.2007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 11/14/2006] [Accepted: 12/11/2006] [Indexed: 01/03/2023] Open
Abstract
During development, motoneurons (MNs) undergo a highly stereotyped, temporally and spatially defined period of programmed cell death (PCD), the result of which is the loss of 40-50% of the original neuronal population. Those MNs that survive are thought to reflect the successful acquisition of limiting amounts of trophic factors from the target. In contrast, maturation of MNs limits the need for target-derived trophic factors, because axotomy of these neurons in adulthood results in minimal neuronal loss. It is unclear whether MNs lose their need for trophic factors altogether or whether, instead, they come to rely on other cell types for nourishment. Astrocytes are known to supply trophic factors to a variety of neuronal populations and thus may nourish MNs in the absence of target-derived factors. We investigated the survival-promoting activities of muscle- and astrocyte-derived secreted factors and found that astrocyte-conditioned media (ACM) was able to save substantially more motoneurons in vitro than muscle-conditioned media (MCM). Our results indicate that both ACM and MCM are significant sources of MN trophic support in vitro and in ovo, but only ACM can rescue MNs after unilateral limb bud removal. Furthermore, we provide evidence suggesting that MCM facilitates the death of a subpopulation of MNs in a p75(NTR) - and caspase-dependent manner; however, maturation in ACM results in MN trophic independence and reduced vulnerability to this negative, pro-apoptotic influence from the target.
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Affiliation(s)
- Anna R Taylor
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA
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Abstract
Olig2 is a basic helix-loop-helix transcription factor that is specifically expressed in oligodendrocyte precursors in the central nervous system. Owing to the absence of oligodendrocytes in the retina, however, the role of olig2 in retinal development remains unclear. In the present study, we demonstrated for the first time that olig2 is expressed in embryonic and postnatal mouse retina. Interestingly, a subset of the bromodeoxyuridine-positive cells expressed olig2 in the embryonic retina. On the other hand, olig2-positive cells did not express nestin, neuron-specific class III beta-tubulin, neurofilament, or various retinal cell-type-specific markers. These results suggest that olig2 is involved in the maintenance of the undifferentiated state of retinal progenitor cells.
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Affiliation(s)
- Kazuaki Nakamura
- Department of Molecular Neurobiology, Tokyo Metropolitan Institute for Neuroscience, Fuchu, Tokyo , Japan
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Harada C, Nakamura K, Namekata K, Okumura A, Mitamura Y, Iizuka Y, Kashiwagi K, Yoshida K, Ohno S, Matsuzawa A, Tanaka K, Ichijo H, Harada T. Role of apoptosis signal-regulating kinase 1 in stress-induced neural cell apoptosis in vivo. THE AMERICAN JOURNAL OF PATHOLOGY 2006; 168:261-9. [PMID: 16400028 PMCID: PMC1592659 DOI: 10.2353/ajpath.2006.050765] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Apoptosis signal-regulating kinase 1 (ASK1) is a mitogen-activated protein kinase kinase kinase that plays an important role in oxidative stress-induced apoptosis. In the present study, we used ASK1 knockout (KO) mice to examine the possibility that ASK1 is involved in the neural cell apoptosis that occurs during retinal development and ischemic injury. ASK1 was expressed in retinal neurons, including retinal ganglion cells (RGCs), but retinal structure and extent of cell death during development were normal in ASK1 KO mice. On the other hand, the strain was less susceptible to ischemic injury, and the number of surviving retinal neurons was significantly increased compared with that in wild-type mice. Interestingly, ischemia-induced phosphorylation of p38 mitogen-activated protein kinase (p38), which mediates RGC apoptosis, was almost completely suppressed in ASK1 KO mice. In such retinas, the numbers of cleaved caspase-3- and TUNEL-positive neurons were apparently decreased compared with those in wild-type mice. Furthermore, cultured RGCs from ASK1 KO mice were resistant to H(2)O(2)-induced apoptosis. Our findings suggest that ASK1 is involved in the neural cell apoptosis after various kinds of oxidative stress. Thus, inhibition of the ASK1-p38 pathway could be useful for the treatment of neurodegenerative diseases including glaucoma.
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Affiliation(s)
- Chikako Harada
- Department of Molecular Neurobiology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashidai, Fuchu, Tokyo 183-8526, Japan.
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