Defective phagocytosis of isolated rod outer segments by RCS rat retinal pigment epithelium in culture

Science ◽  
1977 ◽  
Vol 197 (4307) ◽  
pp. 1001-1003 ◽  
Author(s):  
R. Edwards ◽  
R. Szamier
Keyword(s):  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Rod Outer Segments ◽  
Outer Segments ◽  
Rcs Rat

Ultimate Fate of Rod Outer Segments in the Retinal Pigment Epithelium

1999 ◽  
Vol 12 (5) ◽  
pp. 311-315 ◽  
Author(s):  
GABRIELE THUMANN ◽  
KARL ULRICH BARTZ-SCHMIDT ◽  
NORBERT KOCIOK ◽  
KLAUS HEIMANN ◽  
ULRICH SCHRAEMEYER
Keyword(s):  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Rod Outer Segments ◽  
Outer Segments ◽  
Ultimate Fate

CD36 participates in the phagocytosis of rod outer segments by retinal pigment epithelium

1996 ◽  
Vol 109 (2) ◽  
pp. 387-395 ◽  
Author(s):  
S.W. Ryeom ◽  
J.R. Sparrow ◽  
R.L. Silverstein
Keyword(s):  
Retinal Pigment Epithelium ◽  
Outer Segment ◽  
Retinal Pigment Epithelial ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Immunofluorescent Staining ◽  
Rod Outer Segments ◽  
Photoreceptor Outer Segments ◽  
Pigment Epithelial ◽  
Outer Segments

Mechanisms of phagocytosis are complex and incompletely understood. The retinal pigment epithelium provides an ideal system to study the specific aspects of phagocytosis since an important function of this cell is the ingestion of packets of membranous discs that are normally discarded at the apical ends of rod and cone cells during outer segment renewal. Here we provide evidence that rod outer segment phagocytosis by retinal pigment epithelium is mediated by CD36, a transmembrane glycoprotein which has been previously characterized on hematopoietic cells as a receptor for apoptotic neutrophils and oxidized low density lipoprotein. Immunocytochemical staining with monoclonal and polyclonal antibodies demonstrated CD36 expression by both human and rat retinal pigment epithelium in transverse cryostat sections of normal retina and in primary cultured cells. By western blot analysis of retinal pigment epithelial cell lysates, polyclonal and monoclonal antibodies to CD36 recognized an 88 kDa protein which comigrated with platelet CD36. Furthermore, the synthesis of CD36 mRNA by retinal pigment epithelium was confirmed by reverse transcriptase-PCR using specific CD36 oligonucleotides. The addition of CD36 antibodies to cultured retinal pigment epithelial cells reduced the binding and internalization of 125I-labeled rod outer segments by 60%. Immunofluorescence confocal microscopy confirmed that outer segment uptake was significantly diminished by an antibody to CD36. Moreover, we found that transfection of a human melanoma cell line with CD36 cDNA enabled these cells to bind and internalize isolated photoreceptor outer segments as seen by double immunofluorescent staining for surface bound and total cell-associated rod outer segments, and by measurement of cell-associated 125I-labeled rod outer segments. We conclude that the multifunctional scavenger receptor CD36 participates in the clearance of photoreceptor outer segments by retinal pigment epithelium and thus, participates in the visual process.

scholarly journals THE CIRCADIAN CLOCK IN THE RETINAL PIGMENT EPITHELIUM CONTROLS THE DIURNAL RHYTHM OF PHAGOCYTIC ACTIVITY

2020 ◽  
Author(s):  
Christopher DeVera ◽  
Jendayi Dixon ◽  
Micah A. Chrenek ◽  
Kenkichi Baba ◽  
P. Michael Iuvone ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Circadian Clock ◽  
Phagocytic Activity ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Optomotor Response ◽  
Rpe Cells ◽  
Photoreceptor Outer Segments ◽  
Outer Segments ◽  
Old Mice

AbstractThe diurnal peak of phagocytosis by the retinal pigment epithelium (RPE) of photoreceptor outer segments (POS) is under circadian control, and it is believed that this process involves interactions from both the retina and RPE. Previous studies have demonstrated that a functional circadian clock exists within multiple retinal cell types and RPE cells. Thereby, the aim of the current study was to determine whether the circadian clock in the retina and or RPE controls the diurnal phagocytic peak of photoreceptor outer segments and whether selective disruption of the circadian clock in the RPE would affect RPE cells function and the viability during aging. To that aim, we first generated and validated an RPE tissue-specific KO of the essential clock gene, Bmal1, and then we determined the daily rhythm in phagocytic activity by the RPE in mice lacking a functional circadian clock in the retina or RPE. Then using electroretinography, spectral domain-optical coherence tomography, and optomotor response measurements of visual function we determined the effect of Bmal1 removal in young (6-month old) and old (18-month old) mice. RPE morphology and lipofuscin accumulation was also determined in young and old mice. Our data show that the circadian clock in the RPE controls the daily diurnal phagocytic peak of POS. Surprisingly, the lack of a functional RPE circadian clock or the diurnal phagocytic peak does not result in any detectable age-related degenerative phenotype in the retina or RPE. Thus, our results demonstrate that the loss of the circadian clock in the RPE or the lack of the daily peak in phagocytosis of POS does not result in deterioration of photoreceptors or the RPE during aging.

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