Docosahexaenoic Acid Supply to the Retina and Its Conservation in Photoreceptor Cells by Active Retinal Pigment Epithelium-Mediated Recycling

2015 ◽  
pp. 120-123 ◽  
Author(s):  
Nicolas G. Bazan ◽  
Elena B. Rodriguez de Turco ◽  
William C. Gordon
Keyword(s):  
Retinal Pigment Epithelium ◽  
Docosahexaenoic Acid ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Cells

Pathways for the uptake and conservation of docosahexaenoic acid in photoreceptors and synapses: biochemical and autoradiographic studies

1993 ◽  
Vol 71 (9) ◽  
pp. 690-698 ◽  
Author(s):  
Nicolas G. Bazan ◽  
Elena B. Rodriguez de Turco ◽  
William C. Gordon
Keyword(s):  
Fatty Acid ◽  
Retinal Pigment Epithelium ◽  
Docosahexaenoic Acid ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Cells ◽  
Plasma Lipoproteins ◽  
Rod Photoreceptor ◽  
Excitable Membranes ◽  
The Central Nervous System

Docosahexaenoic acid (22:6n−3) esterified into phospholipids represents by far the most prevalent fatty acid of rod photoreceptor disc membranes and synaptic terminals. During synaptogenesis and photoreceptor biogenesis, plasma lipoproteins, secreted mainly by the liver, are the main source of plasma 22:6n−3 for the central nervous system. This systemic route (the long loop) also operates in mature animals for morphogenesis and maintenance of excitable membranes (e.g., during constant renewal of photoreceptor disc membranes). When radiolabeled 18:3n−3, the dietary precursor of 22:6n−3, is systemically supplied to 3-day-old mouse pups, it is elongated and desaturated in the liver, leading to the synthesis of 22:6n−3 – lipoproteins that shuttle the fatty acid through the bloodstream to retina and brain. When radiolabeled 22:6n−3 was used, a more efficient labeling of brain and retinal lipids was achieved. The retinal pigment epithelium is involved, not only in the uptake of 22:6n−3 from circulating lipoproteins in the choriocapillaris but also in the recycling of 22:6n−3 from degraded phagosomal phospholipids back to the inner segments of photoreceptors (the short loop), following each phagocytic event. An interplay among efficient 22:6n−6 delivery from the liver, selective uptake by retinal pigment epithelium photoreceptor cells, and avid retinal retention may contribute to the enrichment of excitable membranes of the retina with 22:6n−3 – phospholipids.Key words: docosahexaenoic acid, phospholipids, photoreceptors.

JAM-C maintains VEGR2 expression to promote retinal pigment epithelium cell survival under oxidative stress

2017 ◽  
Vol 117 (04) ◽  
pp. 750-757
Author(s):  
Xin Jia ◽  
Chen Zhao ◽  
Qishan Chen ◽  
Yuxiang Du ◽  
Lijuan Huang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Retinal Pigment Epithelium ◽  
Cell Survival ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Retinal Pigment Epithelium Cell ◽  
Photoreceptor Cells ◽  
Rpe Cells

SummaryJunctional adhesion molecule-C (JAM-C) has been shown to play critical roles during development and in immune responses. However, its role in adult eyes under oxidative stress remains poorly understood. Here, we report that JAM-C is abundantly expressed in adult mouse retinae and choroids in vivo and in cultured retinal pigment epithelium (RPE) and photoreceptor cells in vitro. Importantly, both JAM-C expression and its membrane localisation are downregulated by H2O2-induced oxidative stress. Under H2O2-induced oxidative stress, JAM-C is critically required for the survival of human RPE cells. Indeed, loss of JAM-C by siRNA knockdown decreased RPE cell survival. Mechanistically, we show that JAM-C is required to maintain VEGFR2 expression in RPE cells, and VEGFR2 plays an important role in keeping the RPE cells viable since overexpression of VEGFR2 partially restored impaired RPE survival caused by JAM-C knockdown and increased RPE survival. We further show that JAM-C regulates VEGFR2 expression and, in turn, modulates p38 phosphorylation. Together, our data demonstrate that JAM-C plays an important role in maintaining VEGR2 expression to promote RPE cell survival under oxidative stress. Given the vital importance of RPE in the eye, approaches that can modulate JAM-C expression may have therapeutic values in treating diseases with impaired RPE survival.

Docosahexaenoic acid increases in frog retinal pigment epithelium following rod photoreceptor shedding

1992 ◽  
Vol 55 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Huiming Chen ◽  
Rex D. Wiegand ◽  
Cynthia A. Koutz ◽  
Robert E. Anderson
Keyword(s):  
Retinal Pigment Epithelium ◽  
Docosahexaenoic Acid ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Rod Photoreceptor

scholarly journals THE RENEWAL OF PHOTORECEPTOR CELL OUTER SEGMENTS

1967 ◽  
Vol 33 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Richard W. Young
Keyword(s):  
Amino Acid ◽  
Retinal Pigment Epithelium ◽  
Ambient Temperature ◽  
Outer Segment ◽  
Photoreceptor Cell ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Cells ◽  
Radioactive Material ◽  
Retinal Photoreceptor

The utilization of methionine-3H by retinal photoreceptor cells has been studied by radioautographic technique in the rat, mouse, and frog. In all three species, the labeled amino acid is concentrated initially in the inner segment of the cell. Within 24 hr, the radioactive material is displaced to the base of the outer segment, where it accumulates as a distinct reaction band. The reaction band then gradually moves along the outer segment and ultimately disappears at the apex of the cell, which is in contact with the retinal pigment epithelium. These findings are interpreted to indicate that the photoreceptor cell outer segment is continually renewed, by the repeated lamellar apposition of material (membranous discs) at the base of the outer segment, in conjunction with a balanced removal of material at its apex. The outer segment renewal rate is accelerated in frogs when ambient temperature is raised, and is elevated in both frogs and rats when the intensity of retinal illumination is increased.

Transplantation of Human Fetal Retinal Pigment Epithelium Rescues Photoreceptor Cells from in the Royal College of Surgeons Rat Retina.

Retina ◽  
1997 ◽  
Vol 17 (5) ◽  
pp. 469-470
Author(s):  
C. W. Little ◽  
B. Castillo ◽  
D. A. DiLoreto ◽  
C. Cox ◽  
J. Wyatt ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Royal College ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Cells ◽  
Rat Retina

Transplantation of Human Fetal Retinal Pigment Epithelium Rescues Photoreceptor Cells from in the Royal College of Surgeons Rat Retina

Retina ◽  
1997 ◽  
Vol 17 (5) ◽  
pp. 469
Author(s):  
C. W. Little ◽  
B. Castillo ◽  
D. A. DiLoreto ◽  
C. Cox ◽  
J. Wyatt ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Royal College ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Cells ◽  
Rat Retina

Fine structure of the retinal pigment epithelium and photoreceptor cells of an Australian marsupial Setonix brachyurus

1973 ◽  
Vol 51 (10) ◽  
pp. 1093-1100 ◽  
Author(s):  
C. R. Braekevelt
Keyword(s):  
Retinal Pigment Epithelium ◽  
Smooth Endoplasmic Reticulum ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Single Layer ◽  
Photoreceptor Cells ◽  
Rods And Cones ◽  
Outer Border ◽  
Large Lipid Droplet ◽  
Australian Marsupial

The morphology of the retinal pigment epithelium and photoreceptor cells has been studied in the quokka (Setonix brachyurus), an Australian marsupial, by light and electron microscopy.The pigment epithelium is formed by a single layer of cuboidal cells which are separated from the choriocapillaris by multilayered Bruch's membrane. Each epithelial cell is rich in organelles and inclusions, including smooth endoplasmic reticulum, mitochondria, Golgi complexes, phagosomes, and pigment granules. The outer border of the epithelial cells is highly infolded while the inner surface displays numerous processes which surround both rod and cone photoreceptor outer segments.Three photoreceptor types are seen, single rods, single cones, and twin cones. The rod photoreceptors outnumber the cones about 50 to 1 and are smaller and more electron-dense than the cones. The cones possess a large lipid droplet within their inner segments. Twin cones are seen only occasionally. They are formed by two cones lying in close apposition, with each member being morphologically quite similar to the other and to the single cone.Photoreceptor synapses in both rods and cones appear to be formed by superficial and invaginated contacts with bipolar and horizontal cells.

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