Generation of pre-beta 1-HDL and conversion into alpha-HDL. Evidence for disturbed HDL conversion in Tangier disease

Arterioscler Thromb Vasc Biol. 1995 Oct;15(10):1746-54. doi: 10.1161/01.atv.15.10.1746.

Abstract

HDL encompasses several apoA-I-containing particles that differ by size and show pre-beta- or alpha-mobility on agarose gel electrophoresis: pre-beta 1-LpA-I, pre-beta 2-LpA-I, pre-beta 3-LpA-I, alpha-LpA-I2, and alpha-LpA-I3. The quantitatively minor subclass pre-beta 1-LpA-I serves as an initial acceptor of cell-derived cholesterol. In this study, we generated a pre-beta 1-LpA-I-like particle in vitro by the incubation of biotinylated apoA-I with cholesterol-loaded macrophages. Both native pre-beta 1-LpA-I and in vitro-generated pre-beta 1-LpA-I were indistinguishable from lipid-free apoA-I by two-dimensional nondenaturing polyacrylamide gradient gel electrophoresis but exhibited a different size upon gel filtration. In vitro-generated biotin-pre-beta 1-LpA-I took up twofold to threefold more [3H]cholesterol from labeled fibroblasts during a 1-minute pulse incubation than lipid-free apoA-I. The in vitro conversion of biotin-pre-beta 1- LpA-I was investigated in the presence of plasmas of healthy probands and patients with Tangier disease, with apoA-I deficiency, and with lecithin-cholesterol acyltransferase (LCAT) deficiency. Incubation of biotin-pre-beta 1-LpA-I with plasmas either from normoalphalipoproteinemic probands or from a patient with apoA-I deficiency generated a biotinylated particle with the size and electrophoretic mobility of alpha-LpA-I2. This conversion was sensitive to heating at 56 degrees C but not to the removal of calcium. Inhibition of LCAT by dithiobisnitrobenzoic acid led to the formation of alpha-LpA-I3 instead of alpha-LpA-I2.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Apolipoprotein A-I / deficiency
  • Cells, Cultured
  • Female
  • Fibroblasts / metabolism
  • Humans
  • Lipoproteins, HDL / metabolism*
  • Macrophages / metabolism
  • Male
  • Tangier Disease / metabolism*

Substances

  • Apolipoprotein A-I
  • Lipoproteins, HDL