Phospholipids mediated conversion of HDLs generates specific apoA-II pre-β mobility particles

Abstract

Apolipoproteins (apo)A-I and A-II are major proteins of human HDL. The cycling of apoA-I between lipidpoor and lipid-rich forms of HDL plays a key role in the transport of cholesterol by these particles. ApoA-II resides only in part of HDL particles, and little is known about its role in HDL metabolism. Our study investigates the redistribution of apoA-II after HDL remodelling induced by exogenous phospholipids (PL). During incubation with egg yolk lecithin (EYL) liposomes, human HDL became PL-enriched and free cholesterol (FC)-depleted, and lost small amounts of apoA-I and apoA-II. The loss of FC and apolipoproteins correlated with the rise of PL content in HDL. Agarose gel electrophoresis demonstrated the appearance of new pre-b mobility fractions containing apoA-I and apoA-II in liposomes and HDL mixtures. Two-dimensional nondenaturing 2-27% PAGE has shown that the pre-b mobility fraction that appeared at initial liposome-PL/HDL-PL ratio 5:1 consisted of two distinct heterogeneous subpopulations of particles containing either apoA-I or apoA-II. Our study provides evidence that during HDL conversion mediated by PL apoA-II dissociated from HDL particles yielding apoA-II-specific pre-b mobility particles. This observation supports the hypothesis that apoA-II in plasma, like apoA-I, may cycle between lipid-poor and lipid-rich forms of HDL.-Wróblewska, M., B. KortasStempak, A. Szutowicz, and T. Badzio. Phospholipids mediated conversion of HDLs generates specific apoA-II pre-b mobility particles. J. Lipid Res. 2009. 50: 667-675.

Structure of HDL: Particle Subclasses and Molecular Components

“…LpA-I and LpA-I:A-II contain approximately 35 and 65 % of plasma apoA-I, respectively (James et al 1988). On the other hand, approximately half of HDL particles contain apoA-II (Wroblewska et al 2009). In addition to apoA-II, the two subclasses may differ in their content of other proteins, as exemplified by PON1 which preferably associates with LpA-I (Moren et al 2008).…”

Progression of Chronic Kidney Disease Affects HDL Impact on Lipoprotein Lipase (LPL)-Mediated VLDL Lipolysis Efficiency

“…VLDL was isolated by ultracentrifugation [14]. HDL was isolated from infranatant after VLDL separation by combined precipitation-ultracentrifugation procedure [15]. Next, the VLDL and HDL were dialyzed (18 h, 4 ºC) against 0.01 M Tris-HCl buffer, pH 7.4, containing 0.195 M NaCl and 0.01% NaN 3 .…”

Apolipoprotein E gene polymorphism and renal function are associated with apolipoprotein E concentration in patients with chronic kidney disease

“…VLDL was isolated from blood serum by ultracentrifugation [7,29]. HDL was isolated by precipitation of APOB-containing lipoproteins with heparin and manganese chloride from the ultracentrifugal d > 1.006 g/ml fraction [30]. In the serum and in isolated VLDL and HDL fractions the concentration of lipids and apolipoproteins were measured.…”