scholarly journals Conditional knockdown of DNA methyltransferase 1 reveals a key role of retinal pigment epithelium integrity in photoreceptor outer segment morphogenesis

Development ◽  
2013 ◽  
Vol 140 (6) ◽  
pp. 1330-1341 ◽  
Author(s):  
I. O. Nasonkin ◽  
S. L. Merbs ◽  
K. Lazo ◽  
V. F. Oliver ◽  
M. Brooks ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Dna Methyltransferase ◽  
Outer Segment ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Dna Methyltransferase 1 ◽  
Photoreceptor Outer Segment ◽  
Methyltransferase 1

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.

The photoreceptor cytoskeleton visualized

1992 ◽  
Vol 50 (1) ◽  
pp. 480-481
Author(s):  
Beth Burnside
Keyword(s):  
Outer Segment ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Cell Polarization ◽  
Synaptic Proteins ◽  
Cell Functions ◽  
Vertebrate Photoreceptor ◽  
Numerous Cell ◽  
Turn Over

The vertebrate photoreceptor provides a drammatic example of cell polarization. Specialized to carry out phototransduction at its distal end and to synapse with retinal interneurons at its proximal end, this long slender cell has a uniquely polarized morphology which is reflected in a similarly polarized cytoskeleton. Membranes bearing photopigment are localized in the outer segment, a modified sensory cilium. Sodium pumps which maintain the dark current critical to photosensory transduction are anchored along the inner segment plasma membrane between the outer segment and the nucleus.Proximal to the nucleus is a slender axon terminating in specialized invaginating synapses with other neurons of the retina. Though photoreceptor diameter is only 3-8u, its length from the tip of the outer segment to the synapse may be as great as 200μ. This peculiar linear cell morphology poses special logistical problems and has evoked interesting solutions for numerous cell functions. For example, the outer segment membranes turn over by means of a unique mechanism in which new disks are continuously added at the proximal base of the outer segment, while effete disks are discarded at the tip and phagocytosed by the retinal pigment epithelium. Outer segment proteins are synthesized in the Golgi near the nucleus and must be transported north through the inner segment to their sites of assembly into the outer segment, while synaptic proteins must be transported south through the axon to the synapse.The role of the cytoskeleton in photoreceptor motile processes is being intensely investigated in several laboratories.

scholarly journals Role of DNA methyltransferase 1 on the altered eNOS expression in human umbilical endothelium from intrauterine growth restricted fetuses

Epigenetics ◽  
2013 ◽  
Vol 8 (9) ◽  
pp. 944-952 ◽  
Author(s):  
Bernardo J Krause ◽  
Paula M Costello ◽  
Ernesto Muñoz-Urrutia ◽  
Karen A Lillycrop ◽  
Mark A Hanson ◽  
...  
Keyword(s):  
Dna Methyltransferase ◽  
Dna Methyltransferase 1 ◽  
Enos Expression ◽  
Intrauterine Growth ◽  
Methyltransferase 1
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