| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1From the Laboratory of Retinal Cell and Molecular Biology, the Section on Mechanisms of Retinal Diseases, the 2Biological Imaging Core, and 3Veterinary Research and Resources Section, National Eye Institute, National Institutes of Health, Bethesda, Maryland.
PURPOSE. To determine whether plasma low-density lipoprotein (LDL) could be internalized by the RPE and which receptors may be involved. A secondary objective was to determine whether ARPE19 cells could be used as a model to investigate cholesterol processing in the RPE.
METHODS. Commercially available human LDL was labeled with rhodamine or AlexaFluor 568. Immunofluorescence was performed using commercially available antibodies to LDL-R, CD36, and LOX-1. Cells and tissues were imaged using epifluorescence and confocal fluorescence microscopy. Immunoblot analysis and RT-PCR were performed using published techniques.
RESULTS. Intravenously injected rhodamine-labeled LDL (rhoLDL) was detected in the rat RPE by fluorescence confocal microscopy 24 hours after injection. The rhoLDL was present in some areas and absent in others. Cultured ARPE19 cells were also found to internalize LDL and oxidized LDL (oxLDL) readily. Using AlexaFluor 568–labeled LDL we determined that the average cultured RPE cell could internalize approximately 12 to 16 pg of LDL and oxLDL in 24 hours. Immunoblots readily detected the presence of CD36 and LDL-R in the cultured RPE cells but not LOX-1, whereas RT-PCR detected mRNA for all three receptors. Dual-labeling experiments using AlexaFluor 568–labeled LDL and AlexaFluor 488 for the immunolocalization of the receptors showed colocalization of LDL-R with the internalized LDL and CD36 with oxLDL particles.
CONCLUSIONS. Plasma LDL readily enters the RPE through the choriocapillaris but is not found homogenously throughout the retina. This may suggest some form of regulation to the permeability of the fenestrated choroidal endothelial cell junctions. ARPE19 cells are a good model for studying the internalization mechanisms of LDL and oxLDL in vitro. LDL may be used as a vector to carry hydrophobic molecules into the RPE.
This article has been cited by other articles:
|
|
 |
|
  H. Stephan, R. Boeloeni, A. Eggert, N. Bornfeld, and A. Schueler Photodynamic Therapy in Retinoblastoma: Effects of Verteporfin on Retinoblastoma Cell Lines Invest. Ophthalmol. Vis. Sci., July 1, 2008; 49(7): 3158 - 3163. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Bretillon, N. Acar, M. W. Seeliger, M. Santos, M. A. Maire, P. Juaneda, L. Martine, S. Gregoire, C. Joffre, A. M. Bron, et al. ApoB100,LDLR-/- Mice Exhibit Reduced Electroretinographic Response and Cholesteryl Esters Deposits in the Retina Invest. Ophthalmol. Vis. Sci., April 1, 2008; 49(4): 1307 - 1314. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
U. Schmidt-Erfurth, M. Rudolf, M. Funk, C. Hofmann-Rummelt, N.-S. Franz-Haas, Z. Aherrahrou, and U. Schlotzer-Schrehardt Ultrastructural Changes in a Murine Model of Graded Bruch Membrane Lipoidal Degeneration and Corresponding VEGF164 Detection Invest. Ophthalmol. Vis. Sci., January 1, 2008; 49(1): 390 - 398. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Luthra, B. Fardin, J. Dong, D. Hertzog, S. Kamjoo, S. Gebremariam, V. Butani, R. Narayanan, J. K. Mungcal, B. D. Kuppermann, et al. Activation of Caspase-8 and Caspase-12 Pathways by 7-Ketocholesterol in Human Retinal Pigment Epithelial Cells Invest. Ophthalmol. Vis. Sci., December 1, 2006; 47(12): 5569 - 5575. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. R. Rodriguez, S. Alam, and J. W. Lee Cytotoxicity of Oxidized Low-Density Lipoprotein in Cultured RPE Cells Is Dependent on the Formation of 7-Ketocholesterol Invest. Ophthalmol. Vis. Sci., August 1, 2004; 45(8): 2830 - 2837. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
