Photoreceptor outer segment and retinal pigment epithelium in vitamin E deficient rats

1981 ◽  
Vol 216 (2) ◽  
pp. 103-109 ◽  
Author(s):  
Tsugio Amemiya
Keyword(s):  
Vitamin E ◽  
Retinal Pigment Epithelium ◽  
Outer Segment ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Outer Segment

scholarly journals Light-induced Oxidation of Photoreceptor Outer Segment Phospholipids Generates Ligands for CD36-mediated Phagocytosis by Retinal Pigment Epithelium

2006 ◽  
Vol 281 (7) ◽  
pp. 4222-4230 ◽  
Author(s):  
Mingjiang Sun ◽  
Silvia C. Finnemann ◽  
Maria Febbraio ◽  
Lian Shan ◽  
Suresh P. Annangudi ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Outer Segment ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Outer Segment

scholarly journals Fast voltage sensitivity in retinal pigment epithelium: sodium channels and their novel role in phagocytosis

2017 ◽  
Author(s):  
Julia K. Johansson ◽  
Teemu O. Ihalainen ◽  
Heli Skottman ◽  
Soile Nymark
Keyword(s):  
Retinal Pigment Epithelium ◽  
Sodium Channels ◽  
Connexin 43 ◽  
Outer Segment ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Cell Junctions ◽  
Voltage Sensitivity ◽  
Photoreceptor Outer Segment ◽  
Junction Protein

AbstractDespite the discoveries of voltage-gated sodium channels (Nav) from a number of non-excitable cell types, the presence of Nav-mediated currents in cells of the retinal pigment epithelium (RPE) has been dismissed as a cell culture artifact. Here, we challenge this notion by demonstrating functional Nav1.4-Nav1.6 and Nav1.8 channels in human embryonic stem cell derived and mouse RPE. Importantly, we show that Navs are involved in photoreceptor outer segment phagocytosis: blocking their activity significantly reduces the efficiency of this process. Consistent with this role, Nav1.8 co-localizes with the endosomal marker Rab7 and, during phagocytosis, with opsin. Nav1.4 localizes strongly to the cell-cell junctions together with the gap junction protein Connexin 43. During phagocytosis, both are localized to the phagosomes with a concurrent decrease in the junctional localization. Our study demonstrates that Navs give the capacity of fast electrical signaling to RPE and that Navs play a novel role in photoreceptor outer segment phagocytosis.

scholarly journals Sveinsson chorioretinal atrophy: the mildest changes are located in the photoreceptor outer segment/retinal pigment epithelium junction

2007 ◽  
Vol 85 (8) ◽  
pp. 862-867 ◽  
Author(s):  
Fridbert Jonasson ◽  
Birgit Sander ◽  
Thor Eysteinsson ◽  
Thomas Jörgensen ◽  
Gordon K. Klintworth
Keyword(s):  
Retinal Pigment Epithelium ◽  
Outer Segment ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Outer Segment ◽  
Chorioretinal Atrophy

Questioning photostasis

2013 ◽  
Vol 30 (4) ◽  
pp. 169-174 ◽  
Author(s):  
ALEXANDER CUNEA ◽  
RANA BEGUM ◽  
DIETER REINISCH ◽  
GLEN JEFFERY
Keyword(s):  
Statistical Analysis ◽  
Retinal Pigment Epithelium ◽  
Outer Segment ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Photoreceptor Outer Segment ◽  
Rpe Cells ◽  
Significant Difference ◽  
Environmental Lighting ◽  
Pigmentation Phenotype

AbstractPhotostasis is a phenomenon where the photoreceptor outer segment (OS) length and its rhodopsin content vary depending on environmental lighting. When light is reduced for extended periods, it is argued that OS lengthen and its rhodopsin concentration rises to increase photon capture in darker environment. Increases in OS length may occur because the retinal pigment epithelium (RPE) cells reduce OS consumption in prolonged darkness. But sample sizes in assessing changes in OS length have been small, and results highly varied with no statistical analysis ever offered. Further, animals used were often albinos, which have abnormal RPE cells. Here we keep pigmented and albino mice for 21 days in darkness and compare OS length with those in a normal 12:12 light/dark environment. We measured approximately 1300 OS but found no statistically significant difference in their lengths between light and dark groups in either pigmentation phenotype, although there was a small trend in the data favoring OS extension in the dark. Given that earlier studies were undertaken on limited samples with no statistical analysis, our data pose serious questions for the notion of mammalian photostasis in terms of significant OS plasticity.

scholarly journals Macrophage and Retinal Pigment Epithelium Phagocytosis

1999 ◽  
Vol 190 (6) ◽  
pp. 861-874 ◽  
Author(s):  
Silvia C. Finnemann ◽  
Enrique Rodriguez-Boulan
Keyword(s):  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Insoluble Fraction ◽  
Αvβ3 Integrin ◽  
Apoptotic Cells ◽  
Integrin Receptor ◽  
Photoreceptor Outer Segment ◽  
Particle Binding ◽  
Pkc Activation

Noninflammatory monocyte macrophages use αvβ3 integrin to selectively bind apoptotic cells, initiating their phagocytic removal. In a related process, the retinal pigment epithelium (RPE) employs αvβ5 integrin to recognize spent photoreceptor outer segment particles (OS). Here, we show that apoptotic cells and OS compete for binding to these receptors, indicating that OS and apoptotic cells expose surface signals recognizable by αvβ3 and αvβ5. Particle binding to αvβ5 required protein kinase C (PKC) activation. In RPE, αvβ5 binding was maximally activated even before any phagocytic challenge and was reduced by PKC inhibitors. In macrophages, it was dormant but became activated upon PKC stimulation. PKC-activated αvβ5-mediated binding in macrophages differed from constitutive binding to the same integrin receptor in RPE cells in that the former followed much faster kinetics, similar to particle binding mediated by αvβ3. Activation of αvβ5 for particle binding correlated with its recruitment into a detergent-insoluble fraction, a process sensitive to pharmacological modulation of PKC in both types of phagocytes. Furthermore, αvβ5 but not αvβ3 particle binding required actin microfilaments. These data constitute the first evidence that noninflammatory phagocytes actively regulate the earliest phase of phagocytic clearance, particle binding, by controlling receptor activity.

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