Phagocytosis of outer segments by retinal pigment epithelium: phagosome- lysosome interactionE Bosch, J Horwitz and D Bok Jules Stein Eye Institute, School of Medicine, University of California, Los Angeles 90024-7008. We studied phagocytosis of rod outer segments (ROS) by the retinal pigmented epithelium (RPE) using rapid freezing, freeze-drying, and electron microscopic immunocytochemistry. Phagocytosis of photoreceptor outer segment tips by the RPE occurs daily, and in rats the shedding of these tips is light-entrained to a circadian rhythm. We studied the phagocytic process 5, 30, 90, and 150 min after light onset or after subjective light onset in rats entrained to a 12-hr dark-12-hr light cycle. Lysosomes were labeled with antibodies to cathepsin D, a major lysosomal enzyme responsible for opsin degradation. Phagosomes and phagolysosomes were recognized because of the lamellar structure of their photoreceptor-derived contents. We found a population of lysosomes that fuse with one another before they interact with phagosomes. This fusion can be triggered either by light or by endogenous circadian mechanisms. We also found that lysosome-phagosome interaction occurs after the ingestion stage is completed and that this interaction occurs in two steps. First, smaller lysosomes fuse with phagosomes. Subsequently, larger lysosomes appear to interact with phagosomes via pore-like or bridge-like structures. It is proposed that interchange of contents takes place through these structures.
Volume 41,
Issue 2,
pp. 253-263,
02/01/1993
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M. Chen, E. Muckersie, M. Robertson, M. Fraczek, J. V. Forrester, and H. Xu Characterization of a Spontaneous Mouse Retinal Pigment Epithelial Cell Line B6-RPE07 Invest. Ophthalmol. Vis. Sci., August 1, 2008; 49(8): 3699 - 3706. [Abstract] [Full Text] [PDF] |
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D. Zhang, M. Brankov, M. T. Makhija, T. Robertson, E. Helmerhorst, J. M. Papadimitriou, and P. E. Rakoczy Correlation between Inactive Cathepsin D Expression and Retinal Changes in mcd2/mcd2 Transgenic Mice Invest. Ophthalmol. Vis. Sci., September 1, 2005; 46(9): 3031 - 3038. [Abstract] [Full Text] [PDF] |
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O. Strauss The Retinal Pigment Epithelium in Visual Function Physiol Rev, July 1, 2005; 85(3): 845 - 881. [Abstract] [Full Text] [PDF] |
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I. Chowers, Y. Kim, R. H. Farkas, T. L. Gunatilaka, A. S. Hackam, P. A. Campochiaro, S. C. Finnemann, and D. J. Zack Changes in Retinal Pigment Epithelial Gene Expression Induced by Rod Outer Segment Uptake Invest. Ophthalmol. Vis. Sci., July 1, 2004; 45(7): 2098 - 2106. [Abstract] [Full Text] [PDF] |
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H. Ida, S. A. Boylan, A. L. Weigel, and L. M. Hjelmeland Age-related changes in the transcriptional profile of mouse RPE/choroid Physiol Genomics, November 11, 2003; 15(3): 258 - 262. [Abstract] [Full Text] [PDF] |
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D. Gibbs, J. Kitamoto, and D. S. Williams Abnormal phagocytosis by retinal pigmented epithelium that lacks myosin VIIa, the Usher syndrome 1B protein PNAS, May 27, 2003; 100(11): 6481 - 6486. [Abstract] [Full Text] [PDF] |
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P. E. Rakoczy, D. Zhang, T. Robertson, N. L. Barnett, J. Papadimitriou, I. J. Constable, and C.-M. Lai Progressive Age-Related Changes Similar to Age-Related Macular Degeneration in a Transgenic Mouse Model Am. J. Pathol., October 1, 2002; 161(4): 1515 - 1524. [Abstract] [Full Text] [PDF] |
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S. C. Finnemann and R. L. Silverstein Differential Roles of CD36 and {alpha}v{beta}5 Integrin in Photoreceptor Phagocytosis by the Retinal Pigment Epithelium J. Exp. Med., November 5, 2001; 194(9): 1289 - 1298. [Abstract] [Full Text] [PDF] |
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G. Hoppe, A. D. Marmorstein, E. A. Pennock, and H. F. Hoff Oxidized Low Density Lipoprotein-Induced Inhibition of Processing of Photoreceptor Outer Segments by RPE Invest. Ophthalmol. Vis. Sci., October 1, 2001; 42(11): 2714 - 2720. [Abstract] [Full Text] [PDF] |
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J. Wassell and M. Boulton A role for vitamin A in the formation of ocular lipofuscin Br. J. Ophthalmol., October 1, 1997; 81(10): 911 - 918. [Abstract] [Full Text] [PDF] |
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A. Bakker, P Webster, W. Jacob, and N. Andrews Homotypic fusion between aggregated lysosomes triggered by elevated [Ca2+]i in fibroblasts J. Cell Sci., January 9, 1997; 110(18): 2227 - 2238. [Abstract] [PDF] |
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