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Selective retinal pigment epithelial cell lipid metabolism and remodeling conserves photoreceptor docosahexaenoic acid following phagocytosis
Author(s) -
Rodriguez de Turco Elena B.,
Parkins Nilda,
Ershov Alexey V.,
Bazan Nicolas G.
Publication year - 1999
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(19990815)57:4<479::aid-jnr7>3.0.co;2-u
Subject(s) - docosahexaenoic acid , retinal , pigment , fatty acid , phagocytosis , biochemistry , lipid metabolism , biology , retinal pigment epithelium , metabolism , cell culture , microbiology and biotechnology , chemistry , polyunsaturated fatty acid , genetics , organic chemistry
Retinal pigment epithelial cells (RPE) actively retrieve and recycle docosahexaenoic acid (DHA, 22:6n‐3) from phagosomal phospholipids back to photoreceptor cells. Here we studied the fate of DHA in primary culture rat RPE cells after feeding with a suspension of rod outer segments (ROS) for 4 hr. Phospholipids (PLs), triacylglycerols (TAG), and free fatty acids were isolated from cells and media by thin layer chromatography (TLC), and their acyl groups quantified by gas liquid chromatography (GLC). In RPE cells, DHA‐PLs increased 3.5‐fold by 4 hr, decreasing thereafter to 1.6‐fold above basal by 24 hr. In contrast, 18:1‐PLs were decreased by 13%–18% below RPE basal values by 8–24 hr, respectively. DHA‐TAG showed the highest increase (21‐fold) by 8 hr. Free DHA displayed a small increase in the cells with a preferential release and accumulation into the media by 24 hr. These results show that in rat RPE cells, photoreceptor cell DHA is transiently incorporated into TAG prior to its release and uptake into 18:1‐PLs. These metabolic pathways and remodeling may be critical in the conservation of this essential, photoreceptor cell fatty acid. J. Neurosci. Res. 57:479–486, 1999. © 1999 Wiley‐Liss, Inc.