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Oxidized LDL promotes vascular endothelial cell pinocytosis via a prooxidation mechanism
Author(s) -
Chow ShuEr,
Lee RenShen,
Shih Stephen H.,
Chen JanKan
Publication year - 1998
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.12.10.823
Subject(s) - pinocytosis , chemistry , membrane ruffling , oxidative stress , biochemistry , stress fiber , low density lipoprotein , foam cell , biophysics , microbiology and biotechnology , cholesterol , lipoprotein , cell , biology , cytoskeleton , endocytosis
Human low density lipoprotein (LDL) is prepared in the presence of antioxidants and is oxidized to different levels (measured by thiobarbituric acid reactive substance) with copper ion. The effects of unoxidized LDL and oxidized LDL (ox‐ LDL) on stress fiber formation, cell membrane ruffling, and pinocytosis (measured by [ 14 C]sucrose uptake) in cultured human umbilical cord vein endothelial cells (EC) are compared. We show that at a concentration range of 100 to 200 μg cholesterol/ ml, both unoxidized LDL and ox‐LDL promote EC elongation and stress fiber formation, but the effect by the latter is more prominent when compared at the same dose range. In addition, ox‐LDL also induces EC membrane ruffling and promotes pinocytosis. These effects are positively correlated with the extent of LDL oxidation and depend on the dose of ox‐LDL. Ox‐LDL‐promoted membrane ruffling and pinocytosis are effectively blocked by brief preexposure of the cells to antioxidants. In contrast, stress fiber formation is not affected by antioxidant pretreatment. Although unoxidized LDL also promotes [ 14 C]sucrose uptake, it is less potent than ox‐LDL and significantly higher concentrations are required to produce a detectable effect. Unlike ox‐LDL, unoxidized LDL‐enhanced pinocytosis is not accompanied by the appearance of membrane ruffling; therefore, they may act via different mechanisms. Elevated pinocytosis may increase transcytotic activity of the endothelium, leading to an increased influx of plasma components such as LDL into the subendothelial space.—Chow, S.‐E., Lee, R.‐S., Shih, S. H., Chen, J.‐K. Oxidized LDL promotes vascular endothelial cell pinocytosis via a prooxidation mechanism. FASEB J . 12, 823–830 (1998)