Cholesterol-laden macrophages are the hallmark of atherogenesis. The class B scavenger receptor, CD36, binds oxidized low density lipoprotein (OxLDL), is found in atherosclerotic lesions, and is upregulated by OxLDL. We tested the effects of α-tocopherol (AT) enrichment of human monocyte-derived macrophages on CD36 expression and cholesteryl ester accumulation. Monocytes isolated from normal volunteers were cultured into macrophages. Macrophages were enriched overnight with various doses of AT (25, 50, and 100 μM). LDL from normal volunteers was oxidized or acetylated (AcLDL) and incubated with macrophages for 48 h at a concentration of 50 or 100 μg/ml. CD36 expression was assessed by flow cytometry. Quantitative analysis of scavenger receptor class A (SR-A) activity was performed with 1,1′-dioctadecyl-3,3,3′,3′-tetramethylin-docarbocyanide perchlorate (DiI)-labeled LDL. CD36 expression was maximal after 8-10 days of culture. AT (≥50 μM) significantly decreased CD36 expression upregulated by OxLDL and AcLDL (P < 0.01). Other antioxidants (β- or γ-tocopherol) or protein kinase C inhibitors failed to decrease CD36 expression. Concomitantly, DiI-AcLDL and DiI-OxLDL uptake was significantly decreased after AT treatment (P < 0.001). Cholesteryl ester accumulation was significantly decreased after AT enrichment (AcLDL + AT, 77% inhibition; OxLDL + AT, 42% inhibition). In conclusion, AT decreases both CD36 and SR-A expression and cholesteryl ester accumulation in human macrophages. This provides additional scientific support for the antiatherogenic properties of AT.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Lipid Research|
|State||Published - 2001|
- Scavenger receptor
- Vitamin E
ASJC Scopus subject areas