Remodeling of apolipoprotein E-containing spherical reconstituted high density lipoproteins by phospholipid transfer protein.
Phospholipid transfer protein (PLTP) transfers phospholipids between HDL and other lipoproteins in plasma. It also remodels spherical, apolipoprotein A-I (apoA-I)-containing HDL into large and small particles in a process involving the dissociation of lipid-free/lipid-poor apoA-I. ApoE is another apolipoprotein that is mostly associated with large, spherical HDL that do not contain apoA-I. Three isoforms of apoE have been identified in human plasma: apoE2, apoE3, and apoE4. This study investigates the remodeling of spherical apoE-containing HDL by PLTP and the ability of PLTP to transfer phospholipids between apoE-containing HDL and phospholipid vesicles. Spherical reconstituted high density lipoproteins (rHDL) containing apoA-I [(A-I)rHDL], apoE2 [(E2)rHDL], apoE3 [(E3)rHDL], or apoE4 [(E4)rHDL] as the sole apolipoprotein were prepared by incubating discoidal rHDL with low density lipoproteins and lecithin:cholesterol acyltransferase. PLTP remodeled the spherical, apoE-containing rHDL into large and small particles without the dissociation of apoE. The PLTP-mediated remodeling of apoE-containing rHDL was more extensive than that of (A-I)rHDL. PLTP transferred phospholipids from small unilamellar vesicles to apoE-containing rHDL in an isoform-dependent manner, but at a rate slower than that for spherical (A-I)rHDL. It is concluded that apoE enhances the capacity of PLTP to remodel HDL but reduces the ability of HDL to participate in PLTP-mediated phospholipid transfers.
Settasatian
Nongnuch
N
Lipid Research Group, Heart Research Institute, Sydney, New South Wales 2050, Australia.
Barter
Philip J
PJ
Rye
Kerry-Anne
KA
D016632:Apolipoprotein A-I / Q000097:blood*; D001057:Apolipoproteins E / Q000097:blood*; D006801:Humans; D008075:Lipoproteins, HDL / Q000097:blood*; D008077:Lipoproteins, LDL / Q000097:blood*; D010316:Particle Size; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000378:metabolism; D049294:Phospholipid Transfer Proteins / Q000097:blood*
D016632:Apolipoprotein A-I; D001057:Apolipoproteins E; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D049294:Phospholipid Transfer Proteins; D007862:Phosphatidylcholine-Sterol O-Acyltransferase