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Zuo Z, Zhang Z, Zhang S, Fan B, Li G. The Molecular Mechanisms Involved in Axonal Degeneration and Retrograde Retinal Ganglion Cell Death. DNA Cell Biol 2023; 42:653-667. [PMID: 37819746 DOI: 10.1089/dna.2023.0180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023] Open
Abstract
Axonal degeneration is a pathologic change common to multiple retinopathies and optic neuropathies. Various pathologic factors, such as mechanical injury, inflammation, and ischemia, can damage retinal ganglion cell (RGC) somas and axons, eventually triggering axonal degeneration and RGC death. The molecular mechanisms of somal and axonal degeneration are distinct but also overlap, and axonal degeneration can result in retrograde somal degeneration. While the mitogen-activated protein kinase pathway acts as a central node in RGC axon degeneration, several newly discovered molecules, such as sterile alpha and Toll/interleukin-1 receptor motif-containing protein 1 and nicotinamide mononucleotide adenylyltransferase 2, also play a critical role in this pathological process following different types of injury. Therefore, we summarize the types of injury that cause RGC axon degeneration and retrograde RGC death and important underlying molecular mechanisms, providing a reference for the identification of targets for protecting axons and RGCs.
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Affiliation(s)
- Zhaoyang Zuo
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
| | - Ziyuan Zhang
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
| | - Siming Zhang
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
| | - Bin Fan
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
| | - Guangyu Li
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, China
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Retinal toxicities of systemic anticancer drugs. Surv Ophthalmol 2021; 67:97-148. [PMID: 34048859 DOI: 10.1016/j.survophthal.2021.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 05/08/2021] [Accepted: 05/10/2021] [Indexed: 01/07/2023]
Abstract
Newer anticancer drugs have revolutionized cancer treatment in the last decade, but conventional chemotherapy still occupies a central position in many cancers, with combination therapy and newer methods of delivery increasing their efficacy while minimizing toxicities. We discuss the retinal toxicities of anticancer drugs with an emphasis on the mechanism of toxicity. Uveitis is seen with the use of v-raf murine sarcoma viral oncogene homolog B editing anticancer inhibitors as well as immunotherapy. Most of the cases are mild with only anterior uveitis, but severe cases of posterior uveitis, panuveitis, and Vogt-Koyanagi-Harada-like disease may also occur. In the retina, a transient neurosensory detachment is observed in almost all patients on mitogen-activated protein kinase kinase (MEK) inhibitors. Microvasculopathy is often seen with interferon α, but vascular occlusion is a more serious toxicity caused by interferon α and MEK inhibitors. Crystalline retinopathy with or without macular edema may occur with tamoxifen; however, even asymptomatic patients may develop cavitatory spaces seen on optical coherence tomography. A unique macular edema with angiographic silence is characteristic of taxanes. Delayed dark adaptation has been observed with fenretinide. Interestingly, this drug is finding potential application in Stargardt disease and age-related macular degeneration.
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Luo L, Zhang Y, Chen H, Hu F, Wang X, Xing Z, Albashari AA, Xiao J, He Y, Ye Q. Effects and mechanisms of basic fibroblast growth factor on the proliferation and regenerative profiles of cryopreserved dental pulp stem cells. Cell Prolif 2020; 54:e12969. [PMID: 33332682 PMCID: PMC7848956 DOI: 10.1111/cpr.12969] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/25/2020] [Accepted: 11/28/2020] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVES Various factors could interfere the biological performance of DPSCs during post-thawed process. Yet, little has been known about optimization of the recovery medium for DPSCs. Thus, our study aimed to explore the effects of adding recombinant bFGF on DPSCs after 3-month cryopreservation as well as the underlying mechanisms. MATERIALS AND METHODS DPSCs were extracted from impacted third molars and purified by MACS. The properties of CD146+ DPSCs (P3) were identified by CCK-8 and flow cytometry. After cryopreservation for 3 months, recovered DPSCs (P4) were immediately supplied with a series of bFGF and analysed cellular proliferation by CCK-8. Then, the optimal dosage of bFGF was determined to further identify apoptosis and TRPC1 channel through Western blot. The succeeding passage (P5) from bFGF pre-treated DPSCs was cultivated in bFGF-free culture medium, cellular proliferation and stemness were verified, and pluripotency was analysed by neurogenic, osteogenic and adipogenic differentiation. RESULTS It is found that adding 20 ng/mL bFGF in culture medium could significantly promote the proliferation of freshly thawed DPSCs (P4) through suppressing apoptosis, activating ERK pathway and up-regulating TRPC1. Such proliferative superiority could be inherited to the succeeding passage (P5) from bFGF pre-stimulated DPSCs, meanwhile, stemness and pluripotency have not been compromised. CONCLUSIONS This study illustrated a safe and feasible cell culture technique to rapidly amplify post-thawed DPSCs with robust regenerative potency, which brightening the future of stem cells banking and tissue engineering.
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Affiliation(s)
- Lihua Luo
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Yanni Zhang
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Hongyu Chen
- Department of Stomatology, Ningbo Women and Children Hospital, Ningbo, China
| | - Fengting Hu
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Xiaoyan Wang
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Zhenjie Xing
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | | | - Jian Xiao
- School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Yan He
- Laboratory of Regenerative Medicine, Tianyou Hospital, Wuhan University of Science and Technology, Wuhan, China
| | - Qingsong Ye
- School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China.,Center of Regenerative Medicine, Renmin Hospital of Wuhan University, Wuhan, China
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Application of CNTF or FGF-2 increases the number of M2-like macrophages after optic nerve injury in adult Rana pipiens. PLoS One 2019; 14:e0209733. [PMID: 31048836 PMCID: PMC6507305 DOI: 10.1371/journal.pone.0209733] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/17/2019] [Indexed: 02/07/2023] Open
Abstract
We have previously shown that a single application of the growth factors ciliary
neurotrophic factor (CNTF) or fibroblast growth factor 2 (FGF-2) to the crushed
optic nerve of the frog, Rana pipiens, increases the numbers
and elongation rate of regenerating retinal ganglion cell axons. Here we
investigate the effects of these factors on the numbers and types of macrophages
that invade the regeneration zone. In control PBS-treated nerves, many
macrophages are present 100 μm distal to the crush site at 1 week after injury;
their numbers halve by 2 weeks. A single application of CNTF at the time of
injury triples the numbers of macrophages at 1 week, with this increase compared
to control being maintained at 2 weeks. Application of FGF-2 is equally
effective at 1 week, but the macrophage numbers have fallen to control levels at
2 weeks. Immunostaining with a pan-macrophage marker, ED1, and a marker for
M2-like macrophages, Arg-1, showed that the proportion of the putative M2
phenotype remained at approximately 80% with all treatments. Electron microscopy
of the macrophages at 1 week shows strong phagocytic activity with all
treatments, with many vacuoles containing axon fragments and membrane debris. At
2 weeks with PBS or FGF-2 treatment the remaining macrophages are less
phagocytically active, containing mainly lipid inclusions. With CNTF treatment,
at 2 weeks many of the more numerous macrophages are still phagocytosing axonal
debris, although they also contain lipid inclusions. We conclude that the
increase in macrophage influx seen after growth factor application is beneficial
for the regenerating axons, probably due to more extensive removal of
degenerating distal axons, but also perhaps to secretion of growth-promoting
substances.
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Effects of Transplanted Heparin-Poloxamer Hydrogel Combining Dental Pulp Stem Cells and bFGF on Spinal Cord Injury Repair. Stem Cells Int 2018; 2018:2398521. [PMID: 29765407 PMCID: PMC5892218 DOI: 10.1155/2018/2398521] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 01/30/2018] [Indexed: 12/16/2022] Open
Abstract
Spinal cord injury (SCI) is one of serious traumatic diseases of the central nervous system and has no effective treatment because of its complicated pathophysiology. Tissue engineering strategy which contains scaffolds, cells, and growth factors can provide a promising treatment for SCI. Hydrogel that has 3D network structure and biomimetic microenvironment can support cellular growth and embed biological macromolecules for sustaining release. Dental pulp stem cells (DPSCs), derived from cranial neural crest, possess mesenchymal stem cell (MSC) characteristics and have an ability to provide neuroprotective and neurotrophic properties for SCI treatment. Basic fibroblast growth factor (bFGF) is able to promote cell survival and proliferation and also has beneficial effect on neural regeneration and functional recovery after SCI. Herein, a thermosensitive heparin-poloxamer (HP) hydrogel containing DPSCs and bFGF was prepared, and the effects of HP-bFGF-DPSCs on neuron restoration after SCI were evaluated by functional recovery tests, western blotting, magnetic resonance imaging (MRI), histology evaluation, and immunohistochemistry. The results suggested that transplanted HP hydrogel containing DPSCs and bFGF had a significant impact on spinal cord repair and regeneration and may provide a promising strategy for neuron repair, functional recovery, and tissue regeneration after SCI.
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Lee-Liu D, Méndez-Olivos EE, Muñoz R, Larraín J. The African clawed frog Xenopus laevis: A model organism to study regeneration of the central nervous system. Neurosci Lett 2016; 652:82-93. [PMID: 27693567 DOI: 10.1016/j.neulet.2016.09.054] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/18/2016] [Accepted: 09/28/2016] [Indexed: 12/20/2022]
Abstract
While an injury to the central nervous system (CNS) in humans and mammals is irreversible, amphibians and teleost fish have the capacity to fully regenerate after severe injury to the CNS. Xenopus laevis has a high potential to regenerate the brain and spinal cord during larval stages (47-54), and loses this capacity during metamorphosis. The optic nerve has the capacity to regenerate throughout the frog's lifespan. Here, we review CNS regeneration in frogs, with a focus in X. laevis, but also provide some information about X. tropicalis and other frogs. We start with an overview of the anatomy of the Xenopus CNS, including the main supraspinal tracts that emerge from the brain stem, which play a key role in motor control and are highly conserved across vertebrates. We follow with the advantages of using Xenopus, a classical laboratory model organism, with increasing availability of genetic tools like transgenesis and genome editing, and genomic sequences for both X. laevis and X. tropicalis. Most importantly, Xenopus provides the possibility to perform intra-species comparative experiments between regenerative and non-regenerative stages that allow the identification of which factors are permissive for neural regeneration, and/or which are inhibitory. We aim to provide sufficient evidence supporting how useful Xenopus can be to obtain insights into our understanding of CNS regeneration, which, complemented with studies in mammalian vertebrate model systems, can provide a collaborative road towards finding novel therapeutic approaches for injuries to the CNS.
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Affiliation(s)
- Dasfne Lee-Liu
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile.
| | - Emilio E Méndez-Olivos
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Rosana Muñoz
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Juan Larraín
- Center for Aging and Regeneration, Millennium Nucleus in Regenerative Biology, Faculty of Biological Sciences, P. Universidad Católica de Chile, Alameda 340, Santiago, Chile.
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Exogenous Modulation of Retinoic Acid Signaling Affects Adult RGC Survival in the Frog Visual System after Optic Nerve Injury. PLoS One 2016; 11:e0162626. [PMID: 27611191 PMCID: PMC5017682 DOI: 10.1371/journal.pone.0162626] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 08/25/2016] [Indexed: 02/04/2023] Open
Abstract
After lesions to the mammalian optic nerve, the great majority of retinal ganglion cells (RGCs) die before their axons have even had a chance to regenerate. Frog RGCs, on the other hand, suffer only an approximately 50% cell loss, and we have previously investigated the mechanisms by which the application of growth factors can increase their survival rate. Retinoic acid (RA) is a vitamin A-derived lipophilic molecule that plays major roles during development of the nervous system. The RA signaling pathway is also present in parts of the adult nervous system, and components of it are upregulated after injury in peripheral nerves but not in the CNS. Here we investigate whether RA signaling affects long-term RGC survival at 6 weeks after axotomy. Intraocular injection of all-trans retinoic acid (ATRA), the retinoic acid receptor (RAR) type-α agonist AM80, the RARβ agonist CD2314, or the RARγ agonist CD1530, returned axotomized RGC numbers to almost normal levels. On the other hand, inhibition of RA synthesis with disulfiram, or of RAR receptors with the pan-RAR antagonist Ro-41-5253, or the RARβ antagonist LE135E, greatly reduced the survival of the axotomized neurons. Axotomy elicited a strong activation of the MAPK, STAT3 and AKT pathways; this activation was prevented by disulfiram or by RAR antagonists. Finally, addition of exogenous ATRA stimulated the activation of the first two of these pathways. Future experiments will investigate whether these strong survival-promoting effects of RA are mediated via the upregulation of neurotrophins.
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Duprey-Díaz MV, Blagburn JM, Blanco RE. Optic nerve injury upregulates retinoic acid signaling in the adult frog visual system. J Chem Neuroanat 2016; 77:80-92. [PMID: 27242163 DOI: 10.1016/j.jchemneu.2016.05.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/08/2016] [Accepted: 05/26/2016] [Indexed: 10/21/2022]
Abstract
Retinoic acid (RA) is important during development, in neuronal plasticity, and also in peripheral nervous system regeneration. Here we use the frog visual system as a model to investigate the changes in RA signaling that take place after axonal injury to the central nervous system. Immunocytochemistry was used to localize different components of RA signaling within sections of the retina and optic tectum, namely, the synthetic enzyme retinaldehyde dehydrogenase (RALDH), the RA binding proteins CRABPI and II, the retinoic acid receptors RARα, β and γ, and finally the catabolic enzyme CYP26A1. The levels of these proteins were quantified in extracts of retina and tectum using Western blotting. Animals were studied at 1 week, 3 weeks and 6 weeks after optic nerve transection. At the latter time point the RGC axons were re-entering the optic tectum. All the components of RA signaling were present at low to moderate levels in retinas and tecta of control, unoperated animals. In retina, soon after optic nerve injury there was a large increase in RALDH, some increase in the CRABPs, and a large increase in RGC RARβ and (expression. These increases continued as the RGC axons were regenerating, with the addition of later RARα expression at 6 weeks. At no stage did CYP26A1 expression significantly change. In the tectum the levels of RALDH increased after axotomy and during regrowth of axons (3 weeks), then decreased at 6 weeks, at which time the levels of CYP26A1 increased. Axotomy did not cause an immediate increase in tectal RAR levels but RARα and RARβ increased after 3 weeks and RARγ only after 6 weeks. These results are consistent with RA signaling playing an important role in the survival and regeneration of frog RGCs.
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Affiliation(s)
- Mildred V Duprey-Díaz
- Department of Anatomy and Neurobiology, School of Medicine, University of Puerto Rico, San Juan, PR, USA; Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus, San Juan, PR, USA
| | - Jonathan M Blagburn
- Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus, San Juan, PR, USA
| | - Rosa E Blanco
- Department of Anatomy and Neurobiology, School of Medicine, University of Puerto Rico, San Juan, PR, USA; Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus, San Juan, PR, USA.
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Kuhn HG. Control of Cell Survival in Adult Mammalian Neurogenesis. Cold Spring Harb Perspect Biol 2015; 7:cshperspect.a018895. [PMID: 26511628 DOI: 10.1101/cshperspect.a018895] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The fact that continuous proliferation of stem cells and progenitors, as well as the production of new neurons, occurs in the adult mammalian central nervous system (CNS) raises several basic questions concerning the number of neurons required in a particular system. Can we observe continued growth of brain regions that sustain neurogenesis? Or does an elimination mechanism exist to maintain a constant number of cells? If so, are old neurons replaced, or are the new neurons competing for limited network access among each other? What signals support their survival and integration and what factors are responsible for their elimination? This review will address these and other questions regarding regulatory mechanisms that control cell-death and cell-survival mechanisms during neurogenesis in the intact adult mammalian brain.
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Affiliation(s)
- H Georg Kuhn
- Center for Brain Repair and Rehabilitation, Department of Neuroscience and Physiology, University of Gothenburg, Gothenburg 413 90, Sweden
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Li P, Zhou Z, Shi C, Hou J. Downregulation of basic fibroblast growth factor is associated with femoral head necrosis in broilers. Poult Sci 2015; 94:1052-9. [DOI: 10.3382/ps/pev071] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2015] [Indexed: 12/14/2022] Open
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Kucharska J, Del Río P, Arango-Gonzalez B, Gorza M, Feuchtinger A, Hauck SM, Ueffing M. Cyr61 activates retinal cells and prolongs photoreceptor survival in rd1 mouse model of retinitis pigmentosa. J Neurochem 2014; 130:227-40. [PMID: 24593181 DOI: 10.1111/jnc.12704] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 02/27/2014] [Accepted: 02/27/2014] [Indexed: 01/08/2023]
Abstract
Subretinal injections with glial cell line-derived neurotrophic factor (GDNF) rescue morphology as well as function of rod cells in mouse and rat animal models of retinitis pigmentosa. At the same time, it is postulated that this effect is indirect, mediated by activation of retinal Müller glial (RMG) cells. Here, we show that Cyr61/CCN1, one of the secreted proteins up-regulated in primary RMG after glial cell line-derived neurotrophic factor stimulation, provides neuroprotective and pro-survival capacities: Recombinant Cyr61 significantly reduced photoreceptor (PR) cells death in organotypic cultures of Pde6b(rd1) retinas. To identify stimulated pathways in the retina, we treated Pde6b(rd1) retinal explants with Cyr61 and observed an overall increase in activated Erk1/2 and Stat3 signalling molecules characterized by activation-site-specific phosphorylation. To identify Cyr61 retinal target cells, we isolated primary porcine PR, RMG and retinal pigment epithelium (RPE) cells and exposed them separately to Cyr61. Here, RMG as well as RPE cells responded with induced phosphorylation of Erk1/2, Stat3 and Akt. In PR, no increase in phosphorylation in any of the studied proteins was detected, suggesting an indirect neuroprotective effect of Cyr61. Cyr61 may thus act as an endogenous pro-survival factor for PR, contributing to the complex repertoire of neuroprotective activities generated by RMG and RPE cells. We propose the following model of Cyr61 neuroprotection within the retina: Cyr61 stimulates retinal Müller glial (RMG) and retinal pigment epithelium (RPE) cells and activates PI3K/Akt, mitogen-activated protein kinase(MAPK)/Erk and Janus kinase(JAK)/Stat-signalling pathways in these cells. Phosphorylated Stat3 and Erk1/2 presumably translocate to the nucleus, induce transcriptional changes, which increase secretion of neuroprotective agents that protect photoreceptors (PR) from mutation-induced death.
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Affiliation(s)
- Joanna Kucharska
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany; Research Unit Protein Science, Helmholtz Zentrum München, Neuherberg, Germany
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Vega-Meléndez GS, Blagburn JM, Blanco RE. Ciliary neurotrophic factor and fibroblast growth factor increase the speed and number of regenerating axons after optic nerve injury in adult Rana pipiens. J Neurosci Res 2013; 92:13-23. [PMID: 24166589 DOI: 10.1002/jnr.23303] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/18/2013] [Accepted: 08/27/2013] [Indexed: 11/09/2022]
Abstract
Neurotrophins such as ciliary neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) and growth factors such as fibroblast growth factor (FGF-2) play important roles in neuronal survival and in axonal outgrowth during development. However, whether they can modulate regeneration after optic nerve injury in the adult animal is less clear. The present study investigates the effects of application of these neurotrophic factors on the speed, number, and distribution of regenerating axons in the frog Rana pipiens after optic nerve crush. Optic nerves were crushed and the factors, or phosphate-buffered saline, were applied to the stump or intraocularly. The nerves were examined at different times after axotomy, using anterograde labeling with biotin dextran amine and antibody against growth-associated protein 43. We measured the length, number, and distribution of axons projecting beyond the lesion site. Untreated regenerating axons show an increase in elongation rate over 3 weeks. CNTF more than doubles this rate, FGF-2 increases it, and BDNF has little effect. In contrast, the numbers of regenerating axons that have reached 200 μm at 2 weeks were more than doubled by FGF-2, increased by CNTF, and barely affected by BDNF. The regenerating axons were preferentially distributed in the periphery of the nerve; although the numbers of axons were increased by neurotrophic factor application, this overall distribution was substantially unaffected.
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Affiliation(s)
- Giam S Vega-Meléndez
- Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus, Old San Juan, Puerto Rico; Department of Anatomy and Neurobiology, University of Puerto Rico School of Medicine, San Juan, Puerto Rico
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van der Noll R, Leijen S, Neuteboom GH, Beijnen JH, Schellens JH. Effect of inhibition of the FGFR–MAPK signaling pathway on the development of ocular toxicities. Cancer Treat Rev 2013; 39:664-72. [DOI: 10.1016/j.ctrv.2013.01.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 01/13/2013] [Accepted: 01/16/2013] [Indexed: 10/27/2022]
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Neurotrophic molecules in the treatment of neurodegenerative disease with focus on the retina: status and perspectives. Cell Tissue Res 2013; 353:205-18. [PMID: 23463189 DOI: 10.1007/s00441-013-1585-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 02/07/2013] [Indexed: 01/19/2023]
Abstract
Neurotrophic factors are operationally defined as molecules that promote the survival and differentiation of neurons. Chemically, they belong to divergent classes of molecules but most of the classic neurotrophic factors are proteins. Together with stem cells, viral vectors and genetically engineered cells, they constitute important tools in neuroprotective and regenerative neurobiology. Protein neurotrophic molecules signal through receptors located on the cell membrane. Their downstream signaling exploits pathways that are often common to chemically different factors and frequently target a relatively restricted set of transcription factors, RNA interference and diverse molecular machinery involved in the life vs. death decisions of neurons. Application of neurotrophic factors with the aim of curing or, at least, improving the outcome of neurodegenerative diseases requires (1) profound knowledge of the complex molecular pathology of the disease, (2) the development of animal models as closely as possible resembling the human disease, (3) the identification of target cells to be addressed, (4) intense efforts in chemical engineering to ensure the stability of molecules or to design carriers and small analogs with the ability to cross the blood-brain barrier and (5) scrutinity with regard to possible side effects. Last, but not least, engineering efforts to optimize administration, e.g., by designing the right canulae and infusion devices, are important for the successful translation of preclinical advances into clinical benefit. This article presents selected examples of neurotrophic factors that are currently being tested in animal models or developed for transfer to the clinic, with a major focus on factors with the potential of becoming applicable in various forms of retinal degeneration.
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Hendrickson ML, Ling C, Kalil RE. Degeneration of axotomized projection neurons in the rat dLGN: temporal progression of events and their mitigation by a single administration of FGF2. PLoS One 2012; 7:e46918. [PMID: 23144793 PMCID: PMC3489851 DOI: 10.1371/journal.pone.0046918] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 09/06/2012] [Indexed: 12/13/2022] Open
Abstract
Removal of visual cortex in the rat axotomizes projection neurons in the dorsal lateral geniculate nucleus (dLGN), leading to cytological and structural changes and apoptosis. Biotinylated dextran amine was injected into the visual cortex to label dLGN projection neurons retrogradely prior to removing the cortex in order to quantify the changes in the dendritic morphology of these neurons that precede cell death. At 12 hours after axotomy we observed a loss of appendages and the formation of varicosities in the dendrites of projection neurons. During the next 7 days, the total number of dendrites and the cross-sectional areas of the dendritic arbors of projection neurons declined to about 40% and 20% of normal, respectively. The response of dLGN projection neurons to axotomy was asynchronous, but the sequence of structural changes in individual neurons was similar; namely, disruption of dendrites began within hours followed by cell soma atrophy and nuclear condensation that commenced after the loss of secondary dendrites had occurred. However, a single administration of fibroblast growth factor-2 (FGF2), which mitigates injury-induced neuronal cell death in the dLGN when given at the time of axotomy, markedly reduced the dendritic degeneration of projection neurons. At 3 and 7 days after axotomy the number of surviving dendrites of dLGN projection neurons in FGF-2 treated rats was approximately 50% greater than in untreated rats, and the cross-sectional areas of dendritic arbors were approximately 60% and 50% larger. Caspase-3 activity in axotomized dLGN projection neurons was determined by immunostaining for fractin (fractin-IR), an actin cleavage product produced exclusively by activated caspase-3. Fractin-IR was seen in some dLGN projection neurons at 36 hours survival, and it increased slightly by 3 days. A marked increase in reactivity was seen by 7 days, with the entire dLGN filled with dense fractin-IR in neuronal cell somas and dendrites.
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Affiliation(s)
- Michael L. Hendrickson
- W.M. Keck Laboratory for Biological Imaging, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Changying Ling
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Ronald E. Kalil
- Department of Ophthalmology and Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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Changes in fibroblast growth factor-2 and FGF receptors in the frog visual system during optic nerve regeneration. J Chem Neuroanat 2012; 46:35-44. [PMID: 22940608 DOI: 10.1016/j.jchemneu.2012.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 08/15/2012] [Accepted: 08/16/2012] [Indexed: 02/02/2023]
Abstract
We have previously shown that application of fibroblast growth factor-2 (FGF-2) to cut optic nerve axons enhances retinal ganglion cell (RGC) survival in the adult frog visual system. These actions are mediated via activation of its high affinity receptor FGFR1, enhanced BDNF and TrkB expression, increased CREB phosphorylation, and by promoting MAPK and PKA signaling pathways. The role of endogenous FGF-2 in this system is less well understood. In this study, we determine the distribution of FGF-2 and its receptors in normal animals and in animals at different times after optic nerve cut. Immunohistochemistry and Western blot analysis were conducted using specific antibodies against FGF-2 and its receptors in control retinas and optic tecta, and after one, three, and six weeks post nerve injury. FGF-2 was transiently increased in the retina while it was reduced in the optic tectum just one week after optic nerve transection. Axotomy induced a prolonged upregulation of FGFR1 and FGFR3 in both retina and tectum. FGFR4 levels decreased in the retina shortly after axotomy, whereas a significant increase was detected in the optic tectum. FGFR2 distribution was not affected by the optic nerve lesion. Changes in the presence of these proteins after axotomy suggest a potential role during regeneration.
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Abstract
Central neurons lose the ability for axonal regrowth during development and typically do not regenerate their axons following axotomy once they become mature unless given a growth-permissive environment, for example, a peripheral nerve graft. Retinal ganglion cells (RGCs) of the optic nerve represent a highly useful cell model for the study of neurotrophic factor responsiveness, although the presence of nonneuronal cells in the retina makes it difficult to interpret the direct effects of tested factors on RGCs. Cultures of purified RGCs thus represent an excellent tool for the study of optic nerve cell trophic responsiveness, in terms of both survival and axonal regeneration.
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Affiliation(s)
- Stephen D Skaper
- Department of Pharmacology and Anesthesiology, University of Padova, Padova, Italy.
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Tao YJ, Gao DW, Yu M. TGF-β(1) in retinal ganglion cells in rats with chronic ocular hypertension: its expression and anti-apoptotic effect. Int J Ophthalmol 2011; 4:396-401. [PMID: 22553689 DOI: 10.3980/j.issn.2222-3959.2011.04.15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Accepted: 07/02/2011] [Indexed: 02/02/2023] Open
Abstract
AIM To investigate the anti-apoptotic effect of transforming growth factor beta-1 (TGF-β(1)) on chronic ocular hypertension. METHODS The expression of TGF-β(1) in retinal ganglion cells (RCGs) was measured using the immunohistochemiscal S-P method and real-time PCR in the normally control group, the ocular hypertension group (experimental group A), the ocular hypertension plus antibody intervention group (experimental group B) and the ocular hypertension plus antigen intervention group (experimental group C) at 1, 2, 3 and 4 weeks postoperatively. The count of apoptotic RCGs was measured using the TUNEL method. RESULTS The expression of TGF-β(1 )was significantly higher in experimental group C than that in other three groups (P<0.05). The expression was the lowest in experimental group B (4.17%). A statistically significant difference was noted between the four groups (P<0.01). The count of apoptotic RCGs was statistically significantly lower in experimental group C than that in the experimental groups A and B (P<0.01). A statistically significant difference was noted in the count of apoptotic RCGs between these three experimental groups (P<0.01). CONCLUSION TGF-β(1) can inhibit the apoptosis of RCGs in rats with chronic ocular hypertension.
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Affiliation(s)
- Yong-Jian Tao
- Department of Ophthalmology, Shengjing Hospital of China Medical University, Shenyang 110004, Liaoning Province, China
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Farrell SMJ, Groeger G, Bhatt L, Finnegan S, O’Brien CJ, Cotter TG. bFGF-mediated redox activation of the PI3K/Akt pathway in retinal photoreceptor cells. Eur J Neurosci 2011; 33:632-41. [DOI: 10.1111/j.1460-9568.2010.07559.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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20
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Trophic responsiveness of purified postnatal and adult rat retinal ganglion cells. Cell Tissue Res 2010; 339:297-310. [PMID: 19936794 DOI: 10.1007/s00441-009-0897-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Accepted: 10/09/2009] [Indexed: 12/17/2022]
Abstract
Central neurons lose the ability for axonal re-growth during development and typically do not regenerate their axons following axotomy once they become mature unless given a growth-permissive environment i.e. peripheral nerve graft. In the present study, the growth responsiveness of purified retinal ganglion cells (RGCs) at different ages to neurotrophic factors and Schwann cell (SC)-secreted factors were examined directly. The purity of adult RGCs was 97% as assessed by retrograde labelling with 4,6-diamidino-2-phenylindole. The stability of cultures were demonstrated by long-term survival (30 days) in medium contained brain-derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF) and forskolin (F) (BCF). RGCs from postnatal (P) (P0, P4, P8, P21) and adult (P90) rats showed decreasing levels of survival and neuritogenesis when grown in BCF. In contrast, the opposite was observed in SC-conditioned medium (CM)-treated P0-P8 RGCs which were increasingly responsive. SCCM induced maximal neurite outgrowth in P8 RGCs via the activation of extracellular regulated kinase 1/2 (Erk1/2). Inhibition of mitogen-activated protein kinase-Erk1/2 signaling using an Erk1/2-specific inhibitor (UO126) abolished SCCM-induced Erk1/2 phosphorylation and neuritogenesis completely. Although both SCCM and BCF failed to sustain the same levels of growth in P21 or P90 cultures as observed in P8 cultures, SCCM promoted higher survival and neuritogenesis than BCF-treated adult RGCs. This study is the first report of adult rat RGC purification and demonstrates that mature RGCs need multiple factors for survival and neurite outgrowth.
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Corredor RG, Goldberg JL. Electrical activity enhances neuronal survival and regeneration. J Neural Eng 2009; 6:055001. [DOI: 10.1088/1741-2560/6/5/055001] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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22
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Burdzińska A, Bartoszuk U, Orzechowski A. Preincubation With bFGF but Not Sodium Ascorbate Improves Efficiency of Autologous Transplantation of Muscle-derived Cells Into Urethral Wall. Urology 2009; 73:736-42. [DOI: 10.1016/j.urology.2008.11.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2008] [Revised: 11/08/2008] [Accepted: 11/13/2008] [Indexed: 10/21/2022]
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Wang X, Song Y, Jacobi JL, Tuan RS. Inhibition of histone deacetylases antagonized FGF2 and IL-1beta effects on MMP expression in human articular chondrocytes. Growth Factors 2009; 27:40-9. [PMID: 19107653 PMCID: PMC3612426 DOI: 10.1080/08977190802625179] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Fibroblast growth factor-2 (FGF2) and interleukin-1beta (IL-1beta) stimulate the expression of matrix metalloproteinases (MMPs) in articular chondrocytes, which may contribute to cartilage degradation and development of osteoarthritis. Histone deacetylases (HDACs) have recently been implicated in the regulation of MMP gene expression. To investigate the functional involvement of HDACs in the signaling pathway of FGF2 and IL-1beta, we examined the effects of HDAC inhibition on activities of FGF2 or IL-1beta on gene expression of MMP-1, MMP-3, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs-5 (ADAMTS5), collagen type II, and aggrecan. Human articular chondrocyte cultures were treated with FGF2 or IL-1beta in the presence or absence of HDAC inhibitor (trichostatin A, TSA). Gene expression levels after treatments were assessed using quantitative real time PCR. Results showed that FGF2 and IL-1beta both increased MMP-1 and -13 expression, while IL-1beta also increased MMP-3 mRNA levels. These effects were attenuated in the presence of TSA in a dose dependent manner. In contrast to the effects on MMPs, FGF2 decreased mRNA levels of ADAMTS-5, which was not affected by HDAC inhibition. FGF2, IL-1beta, and TSA inhibited expression of aggrecan, while TSA also decreased mRNA levels of collagen type II. These findings showed that HDAC inhibition antagonized FGF2 and IL-1beta induced MMP expression. Combination of FGF2 and the HDAC inhibitor decreases both anabolic and catabolic genes, which may slow the cartilage turnover and be beneficial for maintaining cartilage integrity.
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Affiliation(s)
| | | | | | - Rocky S. Tuan
- Correspondence: Dr. Rocky S. Tuan, Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis, and Musculoskeletal and Skin Diseases, NIH. Building 50, Room 1523, Bethesda, MD 20892-8022, Phone: 301-451-6854, Fax: 301-435-8017,
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Induction of fibroblast growth factor-2 by electrical stimulation in cultured retinal Mueller cells. Neuroreport 2008; 19:1617-21. [PMID: 18815585 DOI: 10.1097/wnr.0b013e3283140f25] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
It has been demonstrated that retinal Mueller cells, the predominant glial cells, produce neurotrophic factors including basic fibroblast growth factor (FGF-2), and that electrical stimulation enhances the transcription of FGF-2 in the central nervous system. In this study, the effect of electrical stimulation on the induction of FGF-2 in cultured rat Mueller cells was investigated by quantitative real-time polymerase chain reaction and western blotting. Both the messenger RNA and protein of FGF-2 were significantly upregulated after electrical stimulation compared with that of controls. These results suggest that electrical stimulation may directly induce the production of FGF-2 in the retina.
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Blanco RE, Soto I, Duprey-Díaz M, Blagburn JM. Up-regulation of brain-derived neurotrophic factor by application of fibroblast growth factor-2 to the cut optic nerve is important for long-term survival of retinal ganglion cells. J Neurosci Res 2008; 86:3382-92. [PMID: 18655198 PMCID: PMC2587377 DOI: 10.1002/jnr.21793] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Application of basic fibroblast growth factor (FGF-2) to the optic nerve after axotomy promotes the survival of retinal ganglion cells (RGCs) in the frog Rana pipiens and results in a rapid up-regulation of brain-derived neurotrophic factor (BDNF) and TrkB synthesis by the RGCs. Here we investigate whether this up-regulation is maintained over the long term and whether it is required for FGF-2's survival effect. At 6 weeks after axotomy and FGF-2 treatment, we found more RGCs immunopositive for BDNF protein and higher intensity of BDNF and TrkB immunostaining, accompanied by increases in BDNF and TrkB mRNA in RGCs. Application of fluorescently labeled siRNA targeted against BDNF to the cut RGC axons showed that it was transported to the cell bodies. Axonal siRNA treatment eliminated the increases in BDNF immunostaining and mRNA that were induced by FGF-2 and had no effect on TrkB mRNA. This reduction in BDNF synthesis by siRNA greatly reduced the long-term survival effect of FGF-2 on RGCs. This, taken together with previous results, suggests that, although FGF-2 may initially activate survival pathways via ERK signaling, its main long-term survival effects are mediated via its up-regulation of BDNF synthesis by the RGCs.
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Affiliation(s)
- Rosa E Blanco
- Institute of Neurobiology, University of Puerto Rico Medical Sciences Campus, Old San Juan, Puerto Rico.
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26
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Rezende ACS, Vieira AS, Rogério F, Rezende LF, Boschero AC, Negro A, Langone F. Effects of systemic administration of ciliary neurotrophic factor on Bax and Bcl-2 proteins in the lumbar spinal cord of neonatal rats after sciatic nerve transection. ACTA ACUST UNITED AC 2008; 41:1024-8. [PMID: 19039380 DOI: 10.1590/s0100-879x2008005000052] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2008] [Accepted: 10/30/2008] [Indexed: 11/22/2022]
Abstract
Ciliary neurotrophic factor (CNTF) is a cytokine that plays a neuroprotective role in relation to axotomized motoneurons. We determined the effect of daily subcutaneous doses of CNTF (1.2 microg/g for 5 days; N = 13) or PBS (N = 13) on the levels of mRNA for Bcl-2 and Bax, as well as the expression and inter-association of Bcl-2 and Bax proteins, and the survival of motoneurons in the spinal cord lumbar enlargement of 2-day-old Wistar rats after sciatic nerve transection. Five days after transection, the effects were evaluated on histological and molecular levels using Nissl staining, immunoprecipitation, Western blot analysis, and reverse transcriptase-polymerase chain reaction. The motoneuron survival ratio, defined as the ratio between the number of motoneurons counted on the lesioned side vs those on the unlesioned side, was calculated. This ratio was 0.77 +/- 0.02 for CNTF-treated rats vs 0.53 +/- 0.02 for the PBS-treated controls (P < 0.001). Treatment with CNTF modified the level of mRNA, with the expression of Bax RNA decreasing 18% (with a consequent decrease in the level of Bax protein), while the expression of Bcl-2 RNA was increased 87%, although the level of Bcl-2 protein was unchanged. The amount of Bcl-2/Bax heterodimer increased 91% over that found in the PBS-treated controls. These data show, for the first time, that the neuroprotective effect of CNTF on neonatal rat axotomized motoneurons is associated with a reduction in free Bax, due to the inhibition of Bax expression, as well as increased Bcl-2/Bax heterodimerization. Thus, the neuroprotective action of the CNTF on axotomized motoneurons can be related to the inhibition of this apoptotic pathway.
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Affiliation(s)
- A C S Rezende
- Departamento de Fisiologia e Biofísica, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, SP, Brasil
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O'Driscoll C, O'Connor J, O'Brien CJ, Cotter TG. Basic fibroblast growth factor-induced protection from light damage in the mouse retina in vivo. J Neurochem 2007; 105:524-36. [PMID: 18088352 DOI: 10.1111/j.1471-4159.2007.05189.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Basic fibroblast growth factor (bFGF) has proven neuroprotective efficacy in the rodent retina against a diverse array of injurious stimuli. However, there is no consensus to date as to the molecular mechanisms underlying this neuroprotection. The study presented herein demonstrates increased expression of endogenous bFGF in the albino mouse retina in response to acute exposure to sublethal levels of light stress. The increased expression correlates with significant photoreceptor protection from light damage. The neuroprotection is likely to be mediated by bFGF as we demonstrate that a shorter exposure to bright light stress that does not up-regulate bFGF fails to protect photoreceptors from light damage. Furthermore, intravitreal bFGF injection into the retina of mice 3 h prior to light damage affords almost complete photoreceptor protection from light-induced degeneration. In addition, injected bFGF induces the activation of protein kinase B and extracellular signal-regulated kinase 1/2 signalling which correlate directly with the pathways we find to be activated in response to light stress and up-regulated bFGF. Moreover, we demonstrate that both bright light pre-conditioning and intravitreal bFGF injection result in dramatic increases in levels of inactive glycogen synthase kinase 3beta and cyclic AMP response element binding protein phosphorylation indicating a potential mechanism by which bFGF promotes survival of photoreceptors in vivo.
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Affiliation(s)
- Carolyn O'Driscoll
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Cork, Ireland
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28
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Lingor P, Tönges L, Pieper N, Bermel C, Barski E, Planchamp V, Bähr M. ROCK inhibition and CNTF interact on intrinsic signalling pathways and differentially regulate survival and regeneration in retinal ganglion cells. ACTA ACUST UNITED AC 2007; 131:250-63. [PMID: 18063589 DOI: 10.1093/brain/awm284] [Citation(s) in RCA: 181] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Functional regeneration in the CNS is limited by lesion-induced neuronal apoptosis and an environment inhibiting axonal elongation. A principal, yet unresolved question is the interaction between these two major factors. We thus evaluated the role of pharmacological inhibition of rho kinase (ROCK), a key mediator of myelin-derived axonal growth inhibition and CNTF, a potent neurotrophic factor for retinal ganglion cells (RGC), in models of retinal ganglion cell apoptosis and neurite outgrowth/regeneration in vitro and in vivo. Here, we show for the first time that the ROCK inhibitor Y-27632 significantly enhanced survival of RGC in vitro and in vivo. In vitro, the co-application of CNTF and Y-27632 potentiated the effect of either substance alone. ROCK inhibition resulted in the activation of the intrinsic MAPK pathway, and the combination of CNTF and Y-27632 resulted in even more pronounced MAPK activation. While CNTF also induced STAT3 phosphorylation, the additional application of ROCK inhibitor surprisingly diminished the effects of CNTF on STAT3 phosphorylation. ROCK activity was also decreased in an additive manner by both substances. In vivo, both CNTF and Y-27632 enhanced regeneration of RGC into the non-permissive optic nerve crush model and additive effects were observed after combination treatment. Further evaluation using specific inhibitors delineate STAT3 as a negative regulator of neurite growth and positive regulator of cell survival, while MAPK and Akt support neurite growth. These results show that next to neurotrophic factors ROCK inhibition by Y-27632 potently supports survival of lesioned adult CNS neurons. Co-administration of CNTF and Y-27632 results in additive effects on neurite outgrowth and regeneration. The interaction of intracellular signalling pathways may, however, attenuate more pronounced synergy and has to be taken into account for future treatment strategies.
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Affiliation(s)
- Paul Lingor
- 1Department of Neurology, Georg-August-University Göttingen, University Medicine, Waldweg 33, 37073 Göttingen, Germany.
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Zhu S, Korzh V, Gong Z, Low BC. RhoA prevents apoptosis during zebrafish embryogenesis through activation of Mek/Erk pathway. Oncogene 2007; 27:1580-9. [PMID: 17873909 DOI: 10.1038/sj.onc.1210790] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
RhoA small GTPase, as a key regulator for actin cytoskeletal rearrangement, plays pivotal roles during morphogenesis, cytokinesis, phagocytosis and cell migration, but little is known about its signaling mechanism that controls cell survival in vivo. Using zebrafish as a model, we show that non-overlapping antisense morpholinos that block either translation or splicing of rhoA lead to extensive apoptosis during embryogenesis, resulting in overall reduction of body size and body length. These defects are associated with reduced activation of growth-promoting Erk and decreased expression of anti-apoptotic bcl-2. Moreover, ectopic expression of rhoA, Mek or BCL-2 mRNA rescues such phenotypes. Consistently, combined suppression of RhoA and Mek/Erk or Bcl-2 pathways by sub-optimal dose of rhoA morpholino and pharmacological inhibitors for either Mek (U0126) or Bcl-2 (HA 14-1) can induce developmental abnormalities and enhanced apoptosis, similar to those caused by effective RhoA knockdown. Furthermore, U0126 abrogates the rescue by RhoA and MEK but not BCL-2. In contrast, HA 14-1 effectively abolishes all functional rescues by RhoA, MEK or BCL-2, supporting that RhoA prevents apoptosis by activation of Mek/Erk pathway and requiring Bcl-2. These findings reveal an important genetic and functional relationship between RhoA with Mek/Erk and Bcl-2 for cell survival control during embryogenesis.
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Affiliation(s)
- S Zhu
- Cell Signaling and Developmental Biology Laboratory, Department of Biological Sciences, National University of Singapore, Singapore
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30
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Burgos M, Neary JT, González FA. P2Y2 nucleotide receptors inhibit trauma-induced death of astrocytic cells. J Neurochem 2007; 103:1785-800. [PMID: 17868308 DOI: 10.1111/j.1471-4159.2007.04872.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Nucleotides as well as other neurotransmitters are known to be released to the extracellular space upon injury. To determine whether nucleotides acting on P2Y(2) nucleotide receptors promote protective or degenerative events after trauma in astrocytic cells, a well-established model of in vitro brain trauma was applied to 1321N1 cells expressing recombinant P2Y(2) nucleotide receptors (P2Y(2)R-1321N1). Cellular death was examined by measuring DNA fragmentation and caspase activation. Fragmented DNA was observed 48 h post-injury in 1321N1 cells, while P2Y(2) nucleotide receptor expressing cells did not show DNA fragmentation. A laddering pattern of fragmented DNA following injury was observed upon inhibition of P2Y(2) nucleotide receptors with suramin. Time-dependent increases of cleaved caspase-9, a mitochondrial-associated caspase, correlated with injury-induced cellular death. A decreased bax/bcl-2 gene expression ratio was observed in P2Y(2)R-1321N1 cells after traumatic injury, while untransfected 1321N1 cells showed a significant time-dependent increase of the bax/bcl-2 gene expression ratio. Activation of protein kinases was assessed to determine the signaling pathways involved in cell death and survival responses following traumatic injury. In P2Y(2)R-1321N1 and 1321N1 cells p38 phosphorylation was stimulated in a time-dependent manner but the phosphatidylinositol 3-kinase-dependent activation of extracellular signal-regulated kinase 1/2 and protein kinase B (PKB)/Akt was only observed in P2Y(2)R-1321N1 cells after injury. The stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK) signaling pathway was not activated by traumatic injury in either astrocytic cell line. Inhibition of p38 kinase signaling pathway by treatment with PD1693, a MKK3/6 inhibitor, abolished the expression of cleaved caspase-9, the increase in the bax/bcl-2 gene expression ratio, as well as the fragmentation of DNA that followed injury of 1321N1 cells. Taken together, our results demonstrate a novel role for P2Y(2) nucleotide receptors and extracellular nucleotides in mediating survival responses to glial cells undergoing cellular death induced by trauma.
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Affiliation(s)
- Michelle Burgos
- Department of Biochemistry, Medical-Sciences Campus, University of Puerto Rico, San Juan, Puerto Rico
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O'Driscoll C, Wallace D, Cotter TG. bFGF promotes photoreceptor cell survival in vitro by PKA-mediated inactivation of glycogen synthase kinase 3beta and CREB-dependent Bcl-2 up-regulation. J Neurochem 2007; 103:860-70. [PMID: 17714451 DOI: 10.1111/j.1471-4159.2007.04827.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Although there is substantial evidence supporting the neuroprotective efficacy of basic fibroblast growth factor (bFGF) in the rodent retina there is no consensus to date as to the protective mechanism involved. We hypothesise that bFGF can assert its neuroprotective effects directly on mouse photoreceptors transduced via the activation of specific intracellular signalling pathways. In mouse photoreceptor-derived 661W cells, bFGF promoted a rapid inactivation of glycogen synthase kinase 3beta (GSK3beta) by phosphorylation at Ser9. The effects of bFGF on GSK3beta were dependent on protein kinase A (PKA) activation, as inhibition of this pathway blocked inactivation. Furthermore, bFGF protection against oxidative stress was dependent on PKA inactivation of GSK3beta as PKA inhibition attenuated bFGF-induced protection. Furthermore, transfection of cells with mutant dominant negative GSK3betaS9A that cannot be phosphorylated on Ser9 also abrogated neuroprotection. Activation of the transcription factor cAMP-response element binding protein (CREB) and subsequent up-regulation of Bcl-2 in response to bFGF was also dependent on PKA as inhibition with H-89 attenuated increased pCREB levels and Bcl-2 expression. These results indicate that the protective efficacy of bFGF in mouse photoreceptors involves PKA-dependent inactivation of GSK3beta and subsequent up-regulation of Bcl-2 via CREB activation.
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Affiliation(s)
- Carolyn O'Driscoll
- Cell Development and Disease Laboratory, Biochemistry Department, Bioscience Research Institute, University College Cork, Cork, Ireland
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Huang HY, Lin SZ, Kuo JS, Chen WF, Wang MJ. G-CSF protects dopaminergic neurons from 6-OHDA-induced toxicity via the ERK pathway. Neurobiol Aging 2007; 28:1258-69. [PMID: 16839644 DOI: 10.1016/j.neurobiolaging.2006.05.037] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Revised: 05/19/2006] [Accepted: 05/31/2006] [Indexed: 11/28/2022]
Abstract
Granulocyte colony-stimulating factor (G-CSF) is known to have various functions such as induction of survival, proliferation and differentiation of hematopoietic cells. Recently, this factor has also been shown to exhibit neuroprotective effects in rat ischemic brain. In the present study, we first demonstrated that both G-CSF and G-CSF receptor were expressed in dopaminergic neurons in the adult substantia nigra and mesencephalic cultures, suggesting that G-CSF might exert its neuroprotective effects in dopaminergic neurons. Pretreatment with G-CSF protected dopaminergic neurons from 6-hydroxydopamine (6-OHDA)-induced neurotoxicity. Investigation of the underlying mechanisms showed that the extracellular-regulated kinase (ERK), but not Janus kinase/signal transducer(s) and activator(s) of transcription (JAK/STAT), was activated following G-CSF treatment. Moreover, G-CSF also increased phosphorylation of Bad, and restored 6-OHDA-induced decrease in Bcl-xL level. The 6-OHDA-caused caspase-3 activation in dopaminergic neurons was inhibited by G-CSF. Inhibition of ERK abrogated G-CSF-mediated Bad phosphorylation, Bcl-xL expression, activated caspase-3 reduction, and the protection of dopaminergic neurons. Taken together, G-CSF prevents dopaminergic neurons from 6-OHDA-induced toxicity via ERK pathway followed by inhibiting the apoptosis-execution process. These results suggest that G-CSF might have a therapeutic potential in Parkinson's disease.
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Affiliation(s)
- Hsin-Yi Huang
- Neuro-Medical Scientific Center, Buddhist Tzu-Chi General Hospital, Tzu-Chi College of Technology, Hualien 970, Taiwan, ROC
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Spence JR, Aycinena JC, Del Rio-Tsonis K. Fibroblast growth factor-hedgehog interdependence during retina regeneration. Dev Dyn 2007; 236:1161-74. [PMID: 17385725 PMCID: PMC2587111 DOI: 10.1002/dvdy.21115] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The embryonic chick is able to regenerate the retina after it has been removed. We have previously shown that proliferating stem/progenitor cells present in the ciliary body/ciliary marginal zone (CB/CMZ) of the chick eye are responsible for regeneration, which can be induced by ectopic fibroblast growth factor-2 (FGF2) or Sonic hedgehog (Shh). Here, we reveal the mechanisms showing how FGF2 and Shh signaling are interdependent during retina regeneration. If the FGF pathway is inhibited, regeneration stimulated by Shh is inhibited. Likewise, if the Hedgehog pathway is inhibited, regeneration stimulated by FGF2 is inhibited. We examined early signaling events in the CB/CMZ and found that FGF2 or Shh induced a robust Erk phosphorylation during the early stages of retina regeneration. Shh also up-regulated the expression of several members of the FGF signaling pathway. We show that ectopic FGF2 or Shh overexpression increased the number of phosphohistone 3 (PH3)-positive cells in the CB/CMZ and inhibition of either pathway decreased the number of PH3-positive cells. Additionally, both FGF and Hh signaling are required for cell survival in the CB/CMZ, whereas Hh and not FGF signaling plays a role in maintaining the identity of the retinal progenitor population in this region. Combined, our results support a model where the FGF and Hedgehog pathways work together to stimulate retina regeneration.
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Azadi S, Johnson LE, Paquet-Durand F, Perez MTR, Zhang Y, Ekström PAR, van Veen T. CNTF+BDNF treatment and neuroprotective pathways in the rd1 mouse retina. Brain Res 2007; 1129:116-29. [PMID: 17156753 DOI: 10.1016/j.brainres.2006.10.031] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Revised: 10/05/2006] [Accepted: 10/06/2006] [Indexed: 11/22/2022]
Abstract
The rd1 mouse is a relevant model for studying the mechanisms of photoreceptor degeneration in retinitis pigmentosa. Treatment with ciliary neurotrophic factor (CNTF) in combination with brain derived neurotrophic factor (BDNF) is known to rescue photoreceptors in cultured rd1 retinal explants. To shed light on the underlying mechanisms, we studied the effects of 9 days (starting at postnatal day 2) in vitro CNTF+BDNF treatment on the endogenous production of CNTF, BDNF, fibroblast growth factor 2 (FGF2), or the activation of extracellular signal-regulated kinase (ERK), Akt and cAMP-response-element-binding protein (CREB) in retinal explants. In rd1 explants, CNTF+BDNF decreased the number of TUNEL-positive photoreceptors. The treatment also increased endogenous rd1 levels of CNTF and BDNF, but lowered the level of FGF2 expression in rd1 explants. When wild-type explants were treated, endogenous CNTF was similarly increased, while BDNF and FGF2 levels remained unaffected. In addition, treatment of rd1 retinas strongly increased the phosphorylation of ERK, Akt and CREB. In treated wild-type explants, the same parameters were either unchanged (ERK) or decreased (Akt and CREB). The results suggest a role for Akt, ERK and CREB in conveying the neuroprotective effect of CNTF+BDNF treatment in rd1 retinal explants.
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Affiliation(s)
- Seifollah Azadi
- Department of Ophthalmology, University of Lund, BMC-B13, SE-221 84 LUND, Sweden
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Soto I, López-Roca T, Blagburn JM, Blanco RE. Changes in nNOS and NADPH diaphorase in frog retina and tectum after axotomy and FGF-2 application. Brain Res 2006; 1103:65-75. [PMID: 16808907 DOI: 10.1016/j.brainres.2006.05.062] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Revised: 05/18/2006] [Accepted: 05/19/2006] [Indexed: 10/24/2022]
Abstract
We have shown previously that application of fibroblast growth factor-2 (FGF-2) to the cut optic nerve of the frog, Rana pipiens, augments the survival of retinal ganglion cells (RGCs). In this study, we examine the effects of axotomy and FGF-2 treatment upon the distribution of nitric oxide synthase (NOS) and NADPH diaphorase (NADPH-d) activity in the frog retina and tectum. We find that NOS and NADPH-d are largely absent from RGCs but present in amacrine neurons and in retinorecipient tectal layers. Axotomy alone has little effect on NOS expression or diaphorase activity, apart from slightly increasing the levels of expression in a subpopulation of amacrine cells that arborize in the On sublamina of the inner plexiform layer. FGF-2 application to the optic nerve down-regulates NOS expression and activity in the retina and up-regulates it in the tectum, particularly in retinorecipient layers. Electron microscopy of the optic nerve and neurofilament immunostaining of the tectum suggests that FGF-2 treatment increases the number of regenerating retinal axons arriving at the tectum. The effects in the retina and tectum are probably indirect, that in the retina being due to retrograde signaling from RGCs to amacrine neurons, and that in the tectum being due to re-induction of NOS expression in tectal neurons by the arrival of regenerating axons. At this stage, it appears unlikely that these changes in NOS play a role in the FGF-2's survival effect on RGCs.
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Affiliation(s)
- Ileana Soto
- Institute of Neurobiology and Department of Anatomy, University of Puerto Rico Medical Sciences Campus, 201 Boulevard del Valle, San Juan, Puerto Rico
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Park EM, Cho S. Enhanced ERK dependent CREB activation reduces apoptosis in staurosporine-treated human neuroblastoma SK-N-BE(2)C cells. Neurosci Lett 2006; 402:190-4. [PMID: 16678346 DOI: 10.1016/j.neulet.2006.04.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 03/25/2006] [Accepted: 04/05/2006] [Indexed: 11/19/2022]
Abstract
Activation of cAMP response element binding protein (CREB) is implicated in neuronal survival. The mitogen-activated protein kinase/extracellular signal regulated kinase (MAPK/ERK) activates a transcription factor CREB. Previously, we reported that N-acetyl-O-methyldopamine (NAMDA) protects neurons from ischemia via enhancing ERK dependent CREB phosphorylation. To investigate whether NAMDA induces endogenous survival pathways in apoptotic conditions and whether the neuroprotectant enhances a preexisting survival pathway, we determined the degree of ERK-CREB activation and resistance to apoptosis in staurosporine-treated SK-N-BE(2)C neurons. Compared to forskolin-treated apoptotic cultures, NAMDA-treated cultures induced a minimum activation on ERK (pERK) or CREB (pCREB). However, NAMDA enhanced the activation of ERK and CREB in the presence of forskolin (1.7-fold increase for pCREB, 2.1-fold increase for pERK2, p<0.05 from forskolin). The effect was completely blocked by a specific MEK inhibitor U0126, suggesting the involvement of ERK dependent CREB signaling. Cleavage of caspase-3 and poly-(ADP-ribose)-polymerase was additively reduced in cultures treated with NAMDA and forskolin simultaneously, but not in the presence of U0126. The data showed that NAMDA enhances forskolin-induced ERK-CREB activation and potentiates forskolin-induced resistance to apoptosis. The study indicates that enhancing endogenous survival pathways by NAMDA combined with other neuroprotective measure(s) might be a useful strategy to reduce apoptosis.
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Affiliation(s)
- Eun-Mi Park
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, at W.M. Burke Medical Research Institute, White Plains, New York 10065, USA.
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Soto I, Rosenthal JJC, Blagburn JM, Blanco RE. Fibroblast growth factor 2 applied to the optic nerve after axotomy up-regulates BDNF and TrkB in ganglion cells by activating the ERK and PKA signaling pathways. J Neurochem 2006; 96:82-96. [PMID: 16269011 DOI: 10.1111/j.1471-4159.2005.03510.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Application of basic fibroblast growth factor (FGF-2) to the optic nerve after axotomy promotes the survival of retinal ganglion cells (RGCs) in the frog, Rana pipiens. Here we investigate the effects of FGF-2 treatment upon the synthesis of brain-derived neurotrophic factor (BDNF) and its receptor, tyrosine receptor kinase B (TrkB). Axotomy alone increased the amounts of BDNF and TrkB mRNA in RGCs after 1 week and 48 h, respectively; FGF-2 treatment to the nerve accelerated and increased this up-regulation of both. FGF-2 also increased the amounts of phosphorylated cAMP response element binding protein (pCREB) in the retina. Blocking extracellular-regulated kinase (ERK) activation with PD98059 or U0126 prevented the FGF-2-induced up-regulation of BDNF transcription but had no effect on TrkB. However, blocking protein kinase A (PKA) with H89 or Rp-8-Cl-cAMPS reduced the up-regulation of both BDNF and TrkB, and reduced pCREB. In addition, H89 inhibited ERK activation, indicating cross-talk between the pathways. Finally, axonal application of blocking antibody against the FGF receptor 1 (FGFR1) prevented the FGF-2-induced up-regulation of BDNF and TrkB. Our results suggest that FGF-2 acts on RGCs via FGFR1, activating the ERK pathway and CREB to increase BDNF synthesis, and PKA and CREB to increase TrkB synthesis.
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Affiliation(s)
- Ileana Soto
- Institute of Neurobiology and Department of Anatomy, University of Puerto Rico Medical Sciences Campus, 201 Boulevard del Valle, Old San Juan, Puerto Rico 00901
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