OBJECTIVE Lipoprotein(a) is a highly atherogenic lipoprotein, whose metabolism is poorly understood. Currently no safe drugs exists that lower elevated plasma lipoprotein(a) concentrations. We therefore focused on molecular mechanisms that influence apolipoprotein(a) (APOA) biosynthesis. METHODS AND RESULTS Transgenic human APOA mice (tg-APO mice) were injected with 1 mg/kg of recombinant hum...

The class B scavenger receptors SR-BI and CD36 exhibit a broad ligand binding specificity. SR-BI is well characterized as a HDL receptor that mediates selective cholesteryl ester uptake from HDL. CD36, a receptor for oxidized LDL, also binds HDL and mediates selective cholesteryl ester uptake, although much less efficiently than SR-BI. Apolipoprotein A-II (apoA-II), the second most abundant HDL...

Apolipoprotein (apo) A-IV has been proposed to play a role in reverse cholesterol transport. ApoA-IV-containing lipoprotein particles (A-IVLp) were isolated from human plasma and interstitial fluid and characterized by immunoaffinity chromatography. Two major A-IVLp subpopulations, lipoprotein particles containing apoA-IV with apoA-I (LpA-I:A-IV) and lipoprotein particles containing apoA-IV wit...

Pioglitazone, a hypoglycemic agent, has been shown to increase plasma HDL cholesterol, but the mechanism is incompletely understood. We further investigated effects of pioglitazone on transcriptional regulation of apolipoprotein (apo)A-I gene and functional properties of pioglitazone-induced apoA-I-containing particles. Pioglitazone dose-dependently stimulated apoA-I promoter activities in HepG...

In this report, methods are described to isolate milligram quantities of a mutant apolipoprotein A-I (apoA-I) protein for use in structure-function studies. Expression of the L159R apoA-I mutation in humans reduces the concentration of plasma wild-type apoA-I, thus displaying a dominant negative phenotype in vivo. Earlier attempts to express and isolate this mutant protein resulted in extensive...

We examined the role of vagal innervation in lipid-stimulated increases in expression and synthesis of intestinal apolipoprotein A-IV (apoA-IV). In rats with duodenal cannulas and superior mesenteric lymph fistulas given duodenal infusions of lipid emulsion, vagotomy had no effect on either intestinal lipid transport, lymphatic apoA-IV output, or jejunal mucosal apoA-IV synthesis. In rats with ...

The Wisconsin Hypoalpha Mutant (WHAM) chicken has a sex-linked mutation associated with a 90% reduction in high-density lipoprotein (HDL) cholesterol and apolipoprotein A-I (apoA-I). In the present studies, we did not detect a defect in apoA-I synthesis or secretion in liver or intestine. We tested the hypothesis that apoA-I is not binding properly to lipoprotein particles and is undergoing hyp...

Human apolipoprotein (apo) A-IV is a polymorphic plasma protein controlled by two codominant alleles at a single genetic locus. Thus far, five different isoproteins (apoA-IV-O to apoA-N-4) have been described in Caucasians. We have recently identified the nucleotide and amino acid substitutions that are the basis for the most common isoproteins, apoA-IV-l and apoA-IV-2. In this report, the muta...

We have developed a cDNA-dependent scintillation proximity assay (SPA) for rabbit apolipoprotein A-I that follows a classic radioimmunoassay scheme, in that antiserum and radiolabeled ligand are used in a process to quantify a source containing unlabeled ligand. To synthesize radiolabeled ligand we isolated a full-length rabbit apolipoprotein A-I (apoA-I) cDNA, transcribed the corresponding RNA...

Studies were carried out to determine whether apolipoprotein (apo) A-11, like apoA-I, can recruit phospholipid and cholesterol from cell membranes, thereby forming nascent apoA-11-specific HDL. ApoA-I1 and apoA-I were purified from plasma and each was incubated with C H O cells at a concentration of 10 pg/ml. Lipid-containing complexes were isolated from the medium in both cases; the compositio...