Lipoprotein metabolism in human peritoneal cells.
The feasibility of using human cells isolated from peritoneal dialysis effluent as a model for studying lipoprotein and cholesterol metabolism was investigated. Human peritoneal cells degraded low density lipoproteins (LDL) and acetylated LDL (acetyl-LDL) by saturable, high affinity receptor-mediated processes. Positive correlations of the percentage of macrophage cells with degradation rates of LDL (r = 0.742; p < 0.05) and acetyl-LDL (r = 0.931; p < 0.01) indicated that macrophage cells significantly contributed to lipoprotein degradation. LDL receptor-mediated degradation was calcium dependent, and sensitive to pronase and chloroquine treatments. The receptor exhibited specificity for lipoproteins containing apolipoprotein B (apoB) or apolipoprotein E (apoE). Exposure of cells to LDL for 24 hrs significantly down-regulated LDL receptor-mediated degradation. Acetyl-LDL receptor-mediated degradation was calcium independent, inhibited by chloroquine, and was sensitive to pronase and fucoidin treatments. The scavenger receptor exhibited specificity for only acetyl-LDL. These results demonstrate that human peritoneal cells can provide a source of human tissue macrophages suitable for studies of cholesterol and lipoprotein metabolism and offer the opportunity for comparison of metabolic characteristics of in vivo maturated macrophages with available macrophage-like cell lines.
Winzerling
J J
JJ
Department of Nutritional Sciences, University of Arizona, Tucson 85721, USA.
Jouni
Z E
ZE
McNamara
D J
DJ
D000107:Acetylation; D006801:Humans; D006868:Hydrolysis; D007457:Iodine Radioisotopes; D008077:Lipoproteins, LDL / Q000378:metabolism*; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000378:metabolism*; D008565:Membrane Proteins; D010530:Peritoneal Dialysis; D011971:Receptors, Immunologic / Q000378:metabolism; D011973:Receptors, LDL / Q000378:metabolism; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D051122:Scavenger Receptors, Class B
D007457:Iodine Radioisotopes; D008077:Lipoproteins, LDL; D008565:Membrane Proteins; D011971:Receptors, Immunologic; D011973:Receptors, LDL; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; C454739:Scarb1 protein, mouse; D051122:Scavenger Receptors, Class B