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Tripon RG, Oláh J, Nasir T, Csincsik L, Li CL, Szunyogh S, Gong H, Flinn JM, Ovádi J, Lengyel I. Localization of the zinc binding tubulin polymerization promoting protein in the mice and human eye. J Trace Elem Med Biol 2018; 49:222-230. [PMID: 29317136 DOI: 10.1016/j.jtemb.2017.12.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/15/2017] [Accepted: 12/21/2017] [Indexed: 11/20/2022]
Abstract
Tubulin Polymerization Promoting Protein (TPPP/p25) modulates the dynamics and stability of the microtubule network by its bundling and acetylation enhancing activities that can be modulated by the binding of zinc to TPPP/p25. Its expression is essential for the differentiation of oligodendrocytes, the major constituents of the myelin sheath, and has been associated with neuronal inclusions. In this paper, evidence is provided for the expression and localization of TPPP/p25 in the zinc-rich retina and in the oligodendrocytes in the optic nerve. Localization of TPPP/p25 was established by confocal microscopy using calbindin and synaptophysin as markers of specific striations in the inner plexiform layer (IPL) and presynaptic terminals, respectively. Postsynaptic nerve terminals in striations S1, S3 and S5 in the IPL and a subset of amacrine cells show immunopositivity against TPPP/p25 both in mice and human eyes. The co-localization of TPPP/p25 with acetylated tubulin was detected in amacrine cells, oligodendrocyte cell bodies and in synapses in the IPL. Quantitative Western blot revealed that the TPPP/p25 level in the retina was 0.05-0.13 ng/μg protein, comparable to that in the brain. There was a central (from optic nerve head) to peripheral retinal gradient in TPPP/p25 protein levels. Our in vivo studies revealed that the oral zinc supplementation of mice significantly increased TPPP/p25 as well as acetylated tubulin levels in the IPL. These results suggest that TPPP/p25, a microtubule stabilizer can play a role in the organization and reorganization of synaptic connections and visual integration in the eye.
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Affiliation(s)
- Robert G Tripon
- UCL Institute of Ophthalmology, University College London, London, EC1Y 8TB, UK; Department of Histology, University of Medicine and Pharmacy, Tîrgu Mureş, Romania.
| | - Judit Oláh
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, 1117, Hungary.
| | - Tajwar Nasir
- UCL Institute of Ophthalmology, University College London, London, EC1Y 8TB, UK.
| | - Lajos Csincsik
- UCL Institute of Ophthalmology, University College London, London, EC1Y 8TB, UK; Center of Experimental Medicine, The Queen's University Belfast, BT9 7BL, UK.
| | - Chee Lok Li
- UCL Institute of Ophthalmology, University College London, London, EC1Y 8TB, UK.
| | - Sándor Szunyogh
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, 1117, Hungary.
| | - Haiyan Gong
- Department of Ophthalmology, Boston University School of Medicine, MA, USA.
| | - Jane M Flinn
- Department of Psychology, George Mason University Fairfax, VA, USA.
| | - Judit Ovádi
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, 1117, Hungary.
| | - Imre Lengyel
- UCL Institute of Ophthalmology, University College London, London, EC1Y 8TB, UK; Center of Experimental Medicine, The Queen's University Belfast, BT9 7BL, UK.
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Kim JY, Sohn HJ, Lee EY, Goo YS, Kim DW, Seo JH. Expression of αB-Crystallin in the Peripapillary Glial Cells of the Developing Chick Retina. Neurochem Res 2010; 36:76-82. [DOI: 10.1007/s11064-010-0266-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/08/2010] [Indexed: 10/19/2022]
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Howell GR, Libby RT, Jakobs TC, Smith RS, Phalan FC, Barter JW, Barbay JM, Marchant JK, Mahesh N, Porciatti V, Whitmore AV, Masland RH, John SWM. Axons of retinal ganglion cells are insulted in the optic nerve early in DBA/2J glaucoma. J Cell Biol 2007; 179:1523-37. [PMID: 18158332 PMCID: PMC2373494 DOI: 10.1083/jcb.200706181] [Citation(s) in RCA: 457] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Accepted: 11/19/2007] [Indexed: 01/21/2023] Open
Abstract
Here, we use a mouse model (DBA/2J) to readdress the location of insult(s) to retinal ganglion cells (RGCs) in glaucoma. We localize an early sign of axon damage to an astrocyte-rich region of the optic nerve just posterior to the retina, analogous to the lamina cribrosa. In this region, a network of astrocytes associates intimately with RGC axons. Using BAX-deficient DBA/2J mice, which retain all of their RGCs, we provide experimental evidence for an insult within or very close to the lamina in the optic nerve. We show that proximal axon segments attached to their cell bodies survive to the proximity of the lamina. In contrast, axon segments in the lamina and behind the eye degenerate. Finally, the Wld(s) allele, which is known to protect against insults to axons, strongly protects against DBA/2J glaucoma and preserves RGC activity as measured by pattern electroretinography. These experiments provide strong evidence for a local insult to axons in the optic nerve.
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