Morphological Observations of the Apical Surface of Chick Retinal Pigment Epithelium

1989 ◽  
Vol 21 (3) ◽  
pp. 191-199 ◽  
Author(s):  
Kiyoshi Morioka ◽  
Kazushige Hirosawa
Keyword(s):  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Apical Surface

scholarly journals Regulation of phagolysosomal activity by miR-204 critically influences structure and function of retinal pigment epithelium/retina

2019 ◽  
Vol 28 (20) ◽  
pp. 3355-3368 ◽  
Author(s):  
Congxiao Zhang ◽  
Kiyoharu J Miyagishima ◽  
Lijin Dong ◽  
Aaron Rising ◽  
Malika Nimmagadda ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Primary Cultures ◽  
Structure And Function ◽  
Apical Surface ◽  
Altered Expression ◽  
And Function ◽  
The Impact

Abstract MicroRNA-204 (miR-204) is expressed in pulmonary, renal, mammary and eye tissue, and its reduction can result in multiple diseases including cancer. We first generated miR-204−/− mice to study the impact of miR-204 loss on retinal and retinal pigment epithelium (RPE) structure and function. The RPE is fundamentally important for maintaining the health and integrity of the retinal photoreceptors. miR-204−/− eyes evidenced areas of hyper-autofluorescence and defective photoreceptor digestion, along with increased microglia migration to the RPE. Migratory Iba1+ microglial cells were localized to the RPE apical surface where they participated in the phagocytosis of photoreceptor outer segments (POSs) and contributed to a persistent build-up of rhodopsin. These structural, molecular and cellular outcomes were accompanied by decreased light-evoked electrical responses from the retina and RPE. In parallel experiments, we suppressed miR-204 expression in primary cultures of human RPE using anti-miR-204. In vitro suppression of miR-204 in human RPE similarly showed abnormal POS clearance and altered expression of autophagy-related proteins and Rab22a, a regulator of endosome maturation. Together, these in vitro and in vivo experiments suggest that the normally high levels of miR-204 in RPE can mitigate disease onset by preventing generation of oxidative stress and inflammation originating from intracellular accumulation of undigested photoreactive POS lipids. More generally, these results implicate RPE miR-204-mediated regulation of autophagy and endolysosomal interaction as a critical determinant of normal RPE/retina structure and function.

scholarly journals Apical polarization of N-CAM in retinal pigment epithelium is dependent on contact with the neural retina.

1993 ◽  
Vol 121 (2) ◽  
pp. 335-343 ◽  
Author(s):  
D Gundersen ◽  
S K Powell ◽  
E Rodriguez-Boulan
Keyword(s):  
Retinal Pigment Epithelium ◽  
Cultured Cells ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Neural Retina ◽  
Apical Surface ◽  
Neural Cell Adhesion ◽  
Adhesion Role

The retinal pigment epithelium (RPE) is unique among epithelia in that its apical surface does not face a lumen, but, instead, is specialized for interaction with the neural retina. The molecules involved in the interaction of the RPE with the neural retina are not known. We show here that the neural cell adhesion molecule (N-CAM) is found both on the apical surface of RPE in situ and on the outer segments of photoreceptors, fulfilling an important requisite for an adhesion role between both structures. Strikingly, culture of RPE results in rapid redistribution of N-CAM to the basolateral surface. This is not due to an isoform shift, since the N-CAM expressed by cultured cells (140 kD) is the same as that expressed by RPE in vivo. Rather, the reversed polarity of N-CAM appears to result from the disruption of the contact between the RPE and the photoreceptors of the neural retina. We suggest that N-CAM in RPE and photoreceptors participate in these interactions.

scholarly journals Aberrant early endosome biogenesis mediates complement activation in the retinal pigment epithelium in models of macular degeneration

2018 ◽  
Vol 115 (36) ◽  
pp. 9014-9019 ◽  
Author(s):  
Gulpreet Kaur ◽  
Li Xuan Tan ◽  
Gurugirijha Rathnasamy ◽  
Nilsa La Cunza ◽  
Colin J. Germer ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Macular Degeneration ◽  
Complement Activation ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Metabolic Reprogramming ◽  
Apical Surface ◽  
Complement Protein ◽  
Age Related ◽  
Early Endosomes

Abnormally enlarged early endosomes (EEs) are pathological features of neurodegenerative diseases, yet insight into the mechanisms and consequences of EE expansion remains elusive. Here, we report swollen apical EEs in the retinal pigment epithelium (RPE) of aged human donors and in the pigmented Abca4−/− mouse model of Stargardt early-onset macular degeneration. Using high-resolution live-cell imaging, we show that age-related and pathological accumulation of lipofuscin bisretinoids increases ceramide at the apical surface of the RPE, which promotes inward budding and homotypic fusion of EEs. These enlarged endosomes internalize the complement protein C3 into the RPE, resulting in the intracellular generation of C3a fragments. Increased C3a in turn activates the mechanistic target of rapamycin (mTOR), a regulator of critical metabolic processes such as autophagy. The antidepressant desipramine, which decreases ceramide levels by inhibiting acid sphingomyelinase, corrects EE defects in the RPE of Abca4−/− mice. This prevents C3 internalization and limits the formation of C3a fragments within the RPE. Although uncontrolled complement activation is associated with macular degenerations, how complement contributes to pathology in a progressive disease is not well understood. Our studies link expansion of the EE compartment with intracellular complement generation and aberrant mTOR activation, which could set the stage for chronic metabolic reprogramming in the RPE as a prelude to disease. The pivotal role of ceramide in driving EE biogenesis and fusion in the Abca4−/− mice RPE suggests that therapeutic targeting of ceramide could be effective in Stargardt disease and other macular degenerations.

scholarly journals Apical polarity of Na,K-ATPase in retinal pigment epithelium is linked to a reversal of the ankyrin-fodrin submembrane cytoskeleton.

1991 ◽  
Vol 112 (5) ◽  
pp. 863-872 ◽  
Author(s):  
D Gundersen ◽  
J Orlowski ◽  
E Rodriguez-Boulan
Keyword(s):  
Retinal Pigment Epithelium ◽  
Epithelial Cells ◽  
Current Knowledge ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Basolateral Membrane ◽  
Opposite Polarity ◽  
Apical Surface ◽  
Rpe Cells ◽  
Membrane Cytoskeleton

In striking contrast to most other transporting epithelia (e.g., urinary or digestive systems), where Na,K-ATPase is expressed basolaterally, the retinal pigment epithelium (RPE) cells display Na,K-ATPase pumps on the apical membrane. We report here studies aimed to identify the mechanisms underlying this polarity "reversal" of the RPE Na,K-ATPase. By immunofluorescence on thin frozen sections, both alpha and beta subunits were localized on the apical surface of both freshly isolated rat RPE monolayers and RPE monolayers grown in culture. The polarity of the RPE cell is not completely reversed, however, since aminopeptidase, an apically located protein in kidney epithelia, was also found on the apical surface of RPE cells. We used subunit- and isoform-specific cDNA probes to determine that RPE Na,K-ATPase has the same isoform (alpha 1) as the one found in kidney. Ankyrin and fodrin, proteins of the basolateral membrane cytoskeleton of kidney epithelial cells known to be associated with the Na,K-ATPase (Nelson, W. J., and R. W. Hammerton. 1989. J. Cell Biol. 110:349-357) also displayed a reversed apical localization in RPE and were intimately associated to Na,K-ATPase, as revealed by cross-linking experiments. These results indicate that an entire membrane-cytoskeleton complex is assembled with opposite polarity in RPE cells. We discuss our observations in the context of current knowledge on protein sorting mechanisms in epithelial cells.

Apical sorting of influenza hemagglutinin by transcytosis in retinal pigment epithelium

1997 ◽  
Vol 110 (15) ◽  
pp. 1717-1727 ◽  
Author(s):  
V.L. Bonilha ◽  
A.D. Marmorstein ◽  
L. Cohen-Gould ◽  
E. Rodriguez-Boulan
Keyword(s):  
Plasma Membrane ◽  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Subretinal Space ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Apical Surface ◽  
Rpe Cells

The retinal pigment epithelium is endowed with a unique distribution of certain plasma membrane proteins. Na+,K+-ATPase, for instance, is polarized to the apical surface of RPE, rather than to the basolateral surface as in most other epithelia. To study the sorting pathways of RPE cells, we used temperature sensitive mutants of influenza and vesicular stomatitis virus (VSV) to synchronize the transport of hemagglutinin (HA) and VSV G protein (VSV G) along the biosynthetic pathway of the RPE cell line RPE-J. After HA and VSV G accumulated in the trans-Golgi network of RPE-J cells kept at 20 degrees C, transfer to the permissive temperature (32 degrees C) resulted in the transport of both HA and VSV G to the basolateral plasma membrane. Later, while VSV G remained basolateral, HA progressively reversed its polarity, eventually becoming apical. Further analysis demonstrated that the reversal of HA polarity was due to transcytosis of HA from the basolateral to the apical surface of RPE-J cells. To determine whether HA followed a transcytotic route in RPE in vivo, influenza and VSV were injected into the subretinal space of rat eyes. Again, both HA and VSV G were initially observed at the basolateral surface of RPE cells. However, whereas VSV G remained there, HA progressively redistributed to the apical surface. These findings demonstrated that RPE cells use a transcytotic pathway for the targeting of at least some apical proteins to their destination.

The polarity of the plasma membrane protein RET-PE2 in retinal pigment epithelium is developmentally regulated

1996 ◽  
Vol 109 (13) ◽  
pp. 3025-3034 ◽  
Author(s):  
A.D. Marmorstein ◽  
V.L. Bonilha ◽  
S. Chiflet ◽  
J.M. Neill ◽  
E. Rodriguez-Boulan
Keyword(s):  
Retinal Pigment Epithelium ◽  
Laser Scanning ◽  
Biochemical Characterization ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Primary Cultures ◽  
Laser Scanning Confocal Microscopy ◽  
Apical Surface ◽  
Adult Rat ◽  
Interphotoreceptor Matrix

The retinal pigment epithelium (RPE) differs from other epithelia in that the apical surface is not free; instead, it interacts with both photoreceptors and a specialized extracellular material, the interphotoreceptor matrix. Biochemical characterization of the apical and basolateral surfaces of RPE in adult rat eye cups, using a novel in situ biotinylation assay, revealed very different protein compositions and identified a major surface antigen, RET-PE2, with a predominantly apical distribution (approximately 74%). The apical polarity of RET-PE2 was confirmed by immunofluorescence and laser scanning confocal microscopy. In striking contrast, RET-PE2 antigen was preferentially basolateral in primary cultures derived from adult rat RPE and in an immortalized RPE cell line (RPE-J). Under all conditions, RET-PE2 was highly soluble in Triton X-100 (> 81% at 4 degrees C), suggesting that its redistribution was not dependent on changes in cytoskeletal interactions. Analysis of the localization of RET-PE2 in normal rats at postnatal (PN) days 1, 7, and 14 indicated that RET-PE2 redistributes from predominantly basolateral to predominantly apical during that time. Since photoreceptors develop during the first two weeks after birth in the rat, our results suggest that the apical redistribution of RET-PE2 is dependent on the establishment of adult interactions between the RPE and the neural retina and/or the interphotoreceptor matrix, either via direct contacts or through alterations in the intracellular sorting patterns of RPE cells.

Glycosaminoglycan synthesis and secretion by the retinal pigment epithelium: polarized delivery of hyaluronan from the apical surface

2001 ◽  
Vol 114 (1) ◽  
pp. 199-205
Author(s):  
P. deS Senanayake ◽  
A. Calabro ◽  
K. Nishiyama ◽  
J.G. Hu ◽  
D. Bok ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Chondroitin Sulfate ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Basal Medium ◽  
Retinal Pigment Epithelial Cells ◽  
Proteinase K ◽  
Apical Surface ◽  
Glycosaminoglycan Synthesis ◽  
Core Proteins

Hyaluronan and chondroitin sulfate glycosaminoglycan secretion from retinal pigment epithelial cells was established in confluent cultures with high transepithelial resistance. Cell cultures were maintained on Millicell-PCF culture plates, which allow separation of culture medium exposed to apical and basal epithelial surfaces. Following various times in culture, apical and basal culture media were sampled at three day intervals and the glycosaminoglycan content was quantified. Samples were digested with proteinase K to free the glycosaminoglycans from their core proteins, the glycosaminoglycans were ethanol precipitated, and subjected to hyaluronidase SD and chondroitinase ABC digestion to release hyaluronan and chondroitin sulfate disaccharides. Disaccharides were fluorotagged with 2-aminoacridone, separated on polyacrylamide gels and the molar fluorescence in each disaccharide band quantitated. Hyaluronan in the apical medium was significantly higher than in the basal medium (5-12 times) at all recovery intervals (P<0.0001). In contrast, the distribution of unsulfated chondroitin, 4-sulfated chondroitin and 6-sulfated chondroitin disaccharides in apical and basal media was non-polar. Confocal microscopy of cultures probed with a hyaluronan-specific fluorotag established that the HA evident in these cultures is restricted to the apical border of the RPE cultures. Collectively, these data indicate that hyaluronan synthesized by the retinal pigment epithelium is secreted preferentially from the apical surface, suggesting that this tissue is an important source of hyaluronan present in the interphotoreceptor matrix.

Immortalization of polarized rat retinal pigment epithelium

1993 ◽  
Vol 104 (1) ◽  
pp. 37-49 ◽  
Author(s):  
I.R. Nabi ◽  
A.P. Mathews ◽  
L. Cohen-Gould ◽  
D. Gundersen ◽  
E. Rodriguez-Boulan
Keyword(s):  
Retinal Pigment Epithelium ◽  
Tight Junction ◽  
Cell Line ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Primary Cultures ◽  
Neural Retina ◽  
Permissive Temperature ◽  
Apical Surface ◽  
Junction Protein

Rat retinal pigment epithelial (RPE) cells were immortalized by infection with a temperature-sensitive tsA SV40 virus and following cloning and selection for epithelial properties the polarized RPE-J cell line was obtained. At the permissive temperature of 33 degrees C, RPE-J cells behave as an immortalized cell line. When RPE-J cells are grown on nitrocellulose filters coated with a thin layer of Matrigel in the presence of 10(−8) M retinoic acid for 6 days at 33 degrees C and then switched for 33–36 hours to the non-permissive temperature of 40 degrees C, they acquire a differentiated polarized RPE phenotype. Under these growth conditions, RPE-J cells exhibit circumferential staining for the tight-junction protein ZO-1 and acquire a transepithelial resistance of 350 ohms cm2. Morphologically, RPE-J cells exhibit a characteristic RPE morphology with extensive apical microvilli as well as numerous dense bodies including premelanosomes and varied multilamellar structures. Ruthenium red labeling revealed the frequent basal localization of the tight junction. The cells were identified to be of rat RPE origin by their expression of the rat RPE marker RET-PE2 and their ability to phagocytose latex beads. While RPE-J cells are capable of sorting influenza and vesicular stomatitis virus to the apical and basal surfaces, respectively, the Na,K-ATPase is not polarized and the neural cell adhesion molecule, N-CAM, is localized exclusively to the lateral surface. In vivo the apical surface of RPE interacts with the adjacent neural retina and the Na,K-ATPase and N-CAM are both apical; the altered polarity of these two proteins in RPE-J cells may be a consequence of the absence of apical interaction with the neural retina in culture. Previous studies of RPE have been restricted to the use of primary cultures and the RPE-J cell line should prove an excellent model system for the study of the mechanisms determining the characteristic polarity and functions of the retinal pigment epithelium.

scholarly journals Functional and morphological analysis of the subretinal injection of retinal pigment epithelium cells

2012 ◽  
Vol 29 (2) ◽  
pp. 83-93 ◽  
Author(s):  
MAREN ENGELHARDT ◽  
CHINATSU TOSHA ◽  
VANDA S. LOPES ◽  
BRYAN CHEN ◽  
LISA NGUYEN ◽  
...  
Keyword(s):  
Retinal Pigment Epithelium ◽  
Host Cell ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Primary Cultures ◽  
Host Cells ◽  
Apical Surface ◽  
Noninvasive Methods ◽  
Rpe Cells ◽  
Subretinal Injection

AbstractReplacement of retinal pigment epithelium (RPE) cells by transplantation is a potential treatment for some retinal degenerations. Here, we used a combination of invasive and noninvasive methods to characterize the structural and functional consequences of subretinal injection of RPE cells. Pigmented cells from primary cultures were injected into albino mice. Recovery was monitored over 8 weeks by fundus imaging, spectral domain optical coherence tomography (sdOCT), histology, and electroretinography (ERG). sdOCT showed that retinal reattachment was nearly complete by 1 week. ERG response amplitudes were reduced after injection, with cone-mediated function then recovering better than rod function. Photoreceptor cell loss was evident by sdOCT and histology, near the site of injection, and is likely to have been the main cause of incomplete recovery. With microscopy, injected cells were identified by the presence of apical melanosomes. They either established contact with Bruch’s membrane, and thus became part of the RPE monolayer, or were located on the apical surface of the host’s cells, resulting in apposition of the basal surface of the injected cell with the apical surface of the host cell and the formation of a series of desmosomal junctions. RPE cell density was not increased, indicating that the incorporation of an injected cell into the RPE monolayer was concomitant with the loss of a host cell. The transplanted and remaining host cells contained large vacuoles of ingested debris as well as lipofuscin-like granules, suggesting that they had scavenged the excess injected and host cells, and were stressed by the high digestive load. Therefore, although significant functional and structural recovery was observed, the consequences of this digestive stress may be a concern for longer-term health, especially where RPE cell transplantation is used to treat diseases that include lipofuscin accumulation as part of their pathology.

High-voltage electron microscopy of subretinal scar formation

1992 ◽  
Vol 50 (1) ◽  
pp. 486-487
Author(s):  
G.E. Korte ◽  
M. Marko ◽  
G. Hageman
Keyword(s):  
Electron Microscopy ◽  
Monoclonal Antibody ◽  
Retinal Pigment Epithelium ◽  
Glial Cells ◽  
High Voltage ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Sodium Iodate ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron

Sodium iodate iv. damages the retinal pigment epithelium (RPE) in rabbits. Where RPE does not regenerate (e.g., 1,2) Muller glial cells (MC) forma subretinal scar that replaces RPE. The MC response was studied by HVEM in 3D computer reconstructions of serial thick sections, made using the STEREC0N program (3), and the HVEM at the NYS Dept. of Health in Albany, NY. Tissue was processed for HVEM or immunofluorescence localization of a monoclonal antibody recognizing MG microvilli (4).

Sign in / Sign up

Export Citation Format

Share Document