Interaction of lipoproteins with type II pneumocytes in vitro: morphological studies, uptake kinetics and secretion rate of cholesterol.

Apart from dipalmitoyl phosphatidylcholine, cholesterol is the most abundant surfactant lipid. About 90 to 99% of cholesterol of the alveolar surfactant is derived from serum lipoproteins. The aim of this study was to identify the lipoprotein which preferentially supplements type II pneumocytes with cholesterol destined for surfactant production.

Interaction of apo E-containing lipoproteins with the LDL receptor-related protein LRP.

The low-density lipoprotein (LDL) receptor-related protein (LRP) is a multifunctional cell surface receptor that interacts with apolipoprotein E (apo E)-rich lipoproteins, and alpha2-macroglobulin (alpha2-M) in the activated state (alpha2-M*). Whether LRP is a physiologically relevant lipoprotein receptor for naturally occurring apo E-rich lipoproteins, however, is still under discussion. To address this question, we isolated beta-migrating very low density lipoprotein (beta-VLDL) from rabbits by using gel filtration chromatography.

Interaction of apo E-containing lipoproteins with the LDL-receptor-related protein, LRP.

The low density lipoprotein receptor-related protein (LRP) discovered in 1988 (1) was proposed as a candidate for the postulated apo E-binding chylomicron remnant receptor. Recent results suggest LRP to be a multifunctional cell surface receptor which might have a pivotal function in linkage of diverse metabolic pathways not previously considered to be related. Although biochemical evidence for lipoprotein binding to LRP has been presented (rev in 2), the need to add apo E to lipoproteins to demonstrate lipoprotein binding to LRP has raised doubts as to its lipoprotein receptor function.

Oxidized LDL induces serotonin release from blood platelets.

Oxidized low-density lipoprotein (LDL) induces a release of serotonin from morphologically resting platelets and shape changed platelets. This suggests that oxidized LDL, a newly reported weak agonist, contributes to atherogenesis and thrombogenesis by stimulating platelets.

Cell adhesion to the apical pole of epithelium: a function of cell polarity.

Human uterine epithelium displays a distinct polarized organization with apical, lateral, and basal plasma membrane domains. Although non-adhesive throughout most of the menstrual cycle, epithelial cells allow attachment of trophoblast cells to their apical pole during embryo implantation. A recent hypothesis postulates that epithelial cells turn off genes for apical-basal polarity and turn on genes for a more mesenchyme-like phenotype allowing cell-cell interaction with trophoblast.