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Valença A, Mendes-Jorge L, Bonet A, Catita J, Ramos D, Jose-Cunilleras E, Garcia M, Carretero A, Nacher V, Navarro M, Ruberte J. TIM2 modulates retinal iron levels and is involved in blood-retinal barrier breakdown. Exp Eye Res 2020; 202:108292. [PMID: 33065090 DOI: 10.1016/j.exer.2020.108292] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 10/01/2020] [Accepted: 10/05/2020] [Indexed: 12/30/2022]
Abstract
Careful control of iron availability in the retina is central to maintenance of iron homeostasis, as its imbalance is associated with oxidative stress and the progression of several retinopathies. Ferritin, known for its role in iron storage and detoxification, has also been proposed as an iron-transporter protein, through its binding to Scara5 and TIM2 membrane receptors. In this study, the presence and iron-related functions of TIM2 in the mouse retina were investigated. Our results revealed for the first time the presence of TIM2 receptors in the mouse retina, mainly in Müller cells. Experimental TIM2 downregulation in the mouse retina promoted, probably due to a compensatory mechanism, Scara5 overexpression that increased retinal ferritin uptake and induced iron overload. Consecutive reactive oxygen species (ROS) overproduction and vascular endothelial growth factor (VEGF) overexpression led to impaired paracellular and transcellular endothelial transport characterized by tight junction degradation and increased caveolae number. In consequence, blood-retinal barrier (BRB) breakdown and retinal edema were observed. Altogether, these results point to TIM2 as a new modulator of retinal iron homeostasis and as a potential target to counteract retinopathy.
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Affiliation(s)
- Andreia Valença
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477, Lisbon, Portugal; CBATEG - Center for Animal Biotechnology and Gene Therapy, Autonomous University of Barcelona, C/ de La Vall Morona, 08193, Bellaterra (Cerdanyola Del Vallès), Spain
| | - Luísa Mendes-Jorge
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477, Lisbon, Portugal; CBATEG - Center for Animal Biotechnology and Gene Therapy, Autonomous University of Barcelona, C/ de La Vall Morona, 08193, Bellaterra (Cerdanyola Del Vallès), Spain
| | - Aina Bonet
- CBATEG - Center for Animal Biotechnology and Gene Therapy, Autonomous University of Barcelona, C/ de La Vall Morona, 08193, Bellaterra (Cerdanyola Del Vallès), Spain; Department of Animal Health and Anatomy, Faculty of Veterinary, Autonomous University of Barcelona, Travessera Del Turons, 08193, Bellaterra (Cerdanyola Del Vallès), Spain
| | - Joana Catita
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477, Lisbon, Portugal; CBATEG - Center for Animal Biotechnology and Gene Therapy, Autonomous University of Barcelona, C/ de La Vall Morona, 08193, Bellaterra (Cerdanyola Del Vallès), Spain; Faculty of Veterinary Medicine, Lusófona University, Campo Grande 376, 1749-024, Lisbon, Portugal
| | - David Ramos
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477, Lisbon, Portugal; CBATEG - Center for Animal Biotechnology and Gene Therapy, Autonomous University of Barcelona, C/ de La Vall Morona, 08193, Bellaterra (Cerdanyola Del Vallès), Spain
| | - Eduard Jose-Cunilleras
- Department of Animal Medicine and Surgery, Faculty of Veterinary, Autonomous University of Barcelona, Travessera Del Turons, 08193, Bellaterra (Cerdanyola Del Vallès), Spain
| | - Miguel Garcia
- CBATEG - Center for Animal Biotechnology and Gene Therapy, Autonomous University of Barcelona, C/ de La Vall Morona, 08193, Bellaterra (Cerdanyola Del Vallès), Spain
| | - Ana Carretero
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477, Lisbon, Portugal; CBATEG - Center for Animal Biotechnology and Gene Therapy, Autonomous University of Barcelona, C/ de La Vall Morona, 08193, Bellaterra (Cerdanyola Del Vallès), Spain; Department of Animal Health and Anatomy, Faculty of Veterinary, Autonomous University of Barcelona, Travessera Del Turons, 08193, Bellaterra (Cerdanyola Del Vallès), Spain
| | - Victor Nacher
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477, Lisbon, Portugal; CBATEG - Center for Animal Biotechnology and Gene Therapy, Autonomous University of Barcelona, C/ de La Vall Morona, 08193, Bellaterra (Cerdanyola Del Vallès), Spain; Department of Animal Health and Anatomy, Faculty of Veterinary, Autonomous University of Barcelona, Travessera Del Turons, 08193, Bellaterra (Cerdanyola Del Vallès), Spain
| | - Marc Navarro
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477, Lisbon, Portugal; CBATEG - Center for Animal Biotechnology and Gene Therapy, Autonomous University of Barcelona, C/ de La Vall Morona, 08193, Bellaterra (Cerdanyola Del Vallès), Spain; Department of Animal Health and Anatomy, Faculty of Veterinary, Autonomous University of Barcelona, Travessera Del Turons, 08193, Bellaterra (Cerdanyola Del Vallès), Spain
| | - Jesús Ruberte
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Av. Universidade Técnica, 1300-477, Lisbon, Portugal; CBATEG - Center for Animal Biotechnology and Gene Therapy, Autonomous University of Barcelona, C/ de La Vall Morona, 08193, Bellaterra (Cerdanyola Del Vallès), Spain; Department of Animal Health and Anatomy, Faculty of Veterinary, Autonomous University of Barcelona, Travessera Del Turons, 08193, Bellaterra (Cerdanyola Del Vallès), Spain.
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Novales Flamarique I. A vertebrate retina with segregated colour and polarization sensitivity. Proc Biol Sci 2018; 284:rspb.2017.0759. [PMID: 28878058 DOI: 10.1098/rspb.2017.0759] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 07/25/2017] [Indexed: 11/12/2022] Open
Abstract
Besides colour and intensity, some invertebrates are able to independently detect the polarization of light. Among vertebrates, such separation of visual modalities has only been hypothesized for some species of anchovies whose cone photoreceptors have unusual ultrastructure that varies with retinal location. Here, I tested this hypothesis by performing physiological experiments of colour and polarization discrimination using the northern anchovy, Engraulis mordax Optic nerve recordings showed that the ventro-temporal (VT), but not the ventro-nasal (VN), retina was polarization sensitive, and this coincided with the exclusive presence of polarization-sensitive photoreceptors in the VT retina. Spectral (colour) sensitivity recordings from the VN retina indicated the contribution of two spectral cone mechanisms to the optic nerve response, whereas only one contributed to the VT retina. This was supported by the presence of only one visual pigment in the VT retina and two in the VN retina, suggesting that only the VN retina was associated with colour sensitivity. Behavioural tests further demonstrated that anchovies could discriminate colour and the polarization of light using the ventral retina. Thus, in analogy with the visual system of some invertebrates, the northern anchovy has a retina with segregated retinal pathways for colour and polarization vision.
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Affiliation(s)
- Iñigo Novales Flamarique
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada V3J 4M5 .,Department of Biology, University of Victoria, Victoria, British Columbia, Canada V8W 2Y2
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Miyazaki T, Kobayashi M. Morphological characteristics of eyes and retinas of two sardines (Sardinops melanostictus and Etrumeus sadina, Clupeidae) and an anchovy (Engraulis japonicus, Engraulididae). J Morphol 2014; 276:415-24. [PMID: 25488724 DOI: 10.1002/jmor.20350] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 09/05/2014] [Accepted: 11/09/2014] [Indexed: 11/08/2022]
Abstract
The morphology of the eyes and distribution of retinal ganglion cells in two sardine species (Sardinops melanostictus and Etrumeus sadina, Clupeidae) and the Japanese anchovy (Engraulis japonicus, Engraulididae) were investigated anatomically and histologically. The eyes of the sardines faced a slightly dorsolateral direction with the visual field extended obliquely upward. In contrast, the eyes in the anchovy were almost laterally directed. It was hypothesized that the sardines may have an advantage in receiving more downward irradiance compared with the anchovy. The lens muscle was larger in these three species than in many other teleosts, and its surface was entirely melanin-pigmented. Also, the lens muscle directly and tightly adhered to the backside surface of the iris. The relative area of the lens muscle to the area of the lens, a referential value of the relative power of visual accommodation were notably larger in the species studied than in other teleost values that have been previously reported. A higher M/L% value of these clupeid fishes could facilitate fast and wide ranging visual accommodation and was considered to be associated with maintaining and/or re-establishing school formations quickly. Analysis of topographical distributions of cells in the ganglion cell layer showed that cell density was highest in the ventrotemporal quadrant of the retina (temporal of the optic cleft) in all three species. Another potentially important role for the black-pigmented lens muscle may be to block the specialized retinal area from intense sunlight that scatters and irradiates upward or laterally in the surface waters that they inhabit. Thus, the sardine and anchovy may take advantage of efficient detection of visual signals in the frontal-upward direction and further improve visibility of the target in this direction.
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Affiliation(s)
- Taeko Miyazaki
- Department of Life Sciences, Graduate School of Bioresources, Mie University, Kurima-machiya-cho, Tsu, Mie, 514-8507, Japan
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