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The effect of caveolin‐1 (CAV‐1) on fatty acid uptake and CD36 localization in vascular smooth muscle (VSM) cells
Author(s) -
Mattern Heather M.,
Raikar Leena S.,
Hardin Christopher D.
Publication year - 2006
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.20.5.a1293
CD36 is localized to lipid rafts and it is controversial whether it is in caveolae. The purpose of this study was to determine whether CAV‐1 is involved in fatty acid uptake in VSM cells by altering CD36 membrane localization. Fatty acid uptake at different time points was quantified with C 1 ‐BODIPY 500/510 C 12 fluorescence using flow cytometry. A7r5 VSM cells overexpressing CAV‐1 had a significant increase in fatty acid uptake compared to control at 15 sec. Cells treated with 10 mM cyclodextrin (CD) for 30 min to disrupt caveolae tended to have a decrease in fatty acid uptake compared to control with a significant decrease at 10 sec. Immunolabeling for CD36 and CAV‐1 was performed and colocalization analysis revealed a decrease in CAV‐1 overlapping CD36 in CAV‐1 overexpressing cells compared to control cells suggesting that overexpressed CAV‐1 did not overlap with CD36 in the cell. To see if there were changes in the distribution of CD36 in control, CAV‐1 overexpressing, and CD‐treated cells, the ratio of the intensity of CD36 labeling in the first and last 25% of a line scan to the middle 25% was determined. The central to peripheral ratio of CD36 in CAV‐1 overexpressing cells (1.523±0.188, n=4) was significantly higher than in control cells (1.051±0.162, n=4) and CD‐treated cells (0.861±0.279, n=4). CAV‐1 showed a punctuate distribution in all treatment groups. These data suggest that in cells overexpressing CAV‐1, CD36 is relocated to lipid rafts in the plasma membrane, but not to caveolae, where it may play a role in fatty acid uptake in VSM cells. Support: NIH DK 55039 and T32 AR48523