This invited paper is part of the Symposium-in-Print: “Phototoxicity of the Skin and Eye,” in honor of Dr. Colin Chignell.
Sub-lethal Photodynamic Damage to ARPE-19 Cells Transiently Inhibits Their Phagocytic Activity†
Article first published online: 18 MAY 2010
© 2010 The Authors. Journal Compilation. The American Society of Photobiology
Photochemistry and Photobiology
Special Issue: Symposium in Print: "Phototoxicity of the Skin and Eye" in honor of Dr Colin Chignell
Volume 86, Issue 4, pages 772–780, July/August 2010
How to Cite
Olchawa, M., Szewczyk, G., Zaręba, M., Piłat, A., Bzowska, M., Mikołajczyk, T. and Sarna, T. (2010), Sub-lethal Photodynamic Damage to ARPE-19 Cells Transiently Inhibits Their Phagocytic Activity. Photochemistry and Photobiology, 86: 772–780. doi: 10.1111/j.1751-1097.2010.00727.x
- Issue published online: 7 JUL 2010
- Article first published online: 18 MAY 2010
- Received 15 December 2009, accepted 8 February 2010
Efficient phagocytosis of photoreceptor outer segments (POS) membranes by retinal pigment epithelium (RPE) plays a key role in biological renewal of these highly peroxidizable structures. Here, we tested whether photodynamic treatment, mediated by merocyanine 540 (MC 540), rose Bengal or a zinc-substituted chlorophyllide inhibited phagocytic activity of ARPE-19 cells in vitro. Specific phagocytosis of fluorescein-5-isothiocyanate-labeled POS isolated from cow retinas and nonspecific phagocytosis of fluorescent polystyrene beads were measured by flow cytometry. Photodynamic treatment, mediated by all three photosensitizers with sub-threshold doses, induced significant inhibition of the cell-specific phagocytosis. The nonspecific phagocytosis was inhibited by photodynamic treatment mediated only by MC 540. The inhibition of phagocytosis was a reversible phenomenon and after 24 h, the photodynamically treated cells exhibited phagocytic activity that was comparable with that of untreated cells. This study provides proof of principle that sub-threshold photodynamic treatment of ARPE-19 cells with appropriate photosensitizers is a convenient experimental approach for in vitro study of the effects of oxidative stress on specific phagocytic activity of RPE cells. We postulate that oxidative damage to key components of the cell phagocytic machinery may be responsible for severe impairment of its activity, which can lead to retinal degeneration.