Cholesterol Efflux, Cholesterol Esterification, and Cholesteryl Ester Transfer by LpA-I and LpA-I/A-II in Native Plasma

Abstract HDLs encompass structurally heterogeneous particles that fulfill specific functions in reverse cholesterol transport. Two-dimensional nondenaturing polyacrylamide gradient gel electrophoresis (2D-PAGGE) of normal plasma and subsequent immunoblotting with anti–apolipoprotein (apo) A-I antibodies differentiates an abundant particle with electrophoretic α-mobility and less abundant particles with electrophoretic pre-β-mobility (preβ1–LpA-I, preβ2–LpA-I, preβ3–LpA-I). Immunodetection with anti–apoA-II antibodies identifies a single particle with α-mobility. To differentiate α-migrating HDL without apo A-II (α–LpA-I) from those with apoA-II (α–LpA-I/A-II), we combined 2D-PAGGE with immunoadsorption of apoA-II. Incubation of plasma with [3H]cholesterol-labeled fibroblasts in combination with immunosubtracting 2D-PAGGE allowed us to analyze the role of α–LpA-I and α–LpA-I/A-II in the uptake and esterification of cell-derived cholesterol in native plasma. Depending on the duration of incubations with cel...