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The phospholipase activity of a pigment epithelium‐derived factor (PEDF) receptor implies mechanisms of action for cell survival
Author(s) -
Heredia Raul,
Holden Haley,
Becerra S. Patricia
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a249-d
Subject(s) - pedf , transfection , phospholipase a2 , apoptosis , microbiology and biotechnology , viability assay , docosahexaenoic acid , phospholipase , biology , gene silencing , chemistry , biochemistry , fatty acid , enzyme , retinal , gene , polyunsaturated fatty acid
PEDF and the omega‐3 docosahexaenoic acid derivative, neuroprotectin D1, inhibit oxidative stress‐induced apoptosis in retina and pigment epithelial cells. A putative receptor for PEDF, PEDF‐R, is found in membranes of ARPE‐19 cells, and exhibits a potent phospholipase A activity, which is stimulated by PEDF ligand binding. To investigate whether PEDF‐R is involved in the PEDF‐mediated antiapoptotic activity, ARPE‐19 cells exposed to H 2 O 2 were monitored by a label‐free real‐time assay using electronic cell sensor technology. Cell viability decreased with >400 μM H 2 O 2 and preincubation with PEDF for 2 hours prevented such a decrease. ARPE‐19 cells overexpressing and silencing the PEDF‐R gene were created by transfection with specific vectors. The recombinant PEDF‐R partitioned to membrane fractions. The phospholipase A activity in membranes from cells with overexpression vectors was 2.5‐ and 4.5‐fold higher than from untransfected cells and cells transfected with silencing vectors, respectively. These results demonstrate that PEDF protected ARPE‐19 cells against cell death by cytotoxicity and PEDF‐R in ARPE‐19 cell membranes was an active phospholipase that released fatty acids. They suggest the involvement of PEDF‐R in the survival properties of PEDF via docosahexaenoic acid mediated‐signaling events. This research was supported by the Intramural Research Program of the NEI, NIH.