Lecithin:cholesterol acyltransferase-induced transformation of HepG2 lipoproteins.

摘要: Previous studies with the human hepatoblastoma-derived HepG2 cell line in this laboratory have shown that these cells produce high density lipoproteins (HDL) are similar to HDL isolated from patients familial lecithin:cholesterol acyltransferase (LCAT) deficiency. Experiments were, therefore, performed determine whether could be transformed into plasma-like particles by incubation LCAT. Concentrated (d less than 1.235 g/ml) were incubated purified LCAT or lipoprotein-deficient plasma (LPDP) for 4, 12, 24 h at 37 degrees C. control samples possessed excess phospholipid and unesterified cholesterol relative appeared as a mixed population of small spherical (7.8 +/- 1.3 nm) larger discoidal (17.7 4.9 nm long axis) electron microscopy. Nondenaturing gradient gel analysis (GGE) showed major peaks banding 7.4, 10.0, 11.1, 12.2, 14.7 nm. Following 4-h 12-h LPDP incubations, mostly microscopy 10.1 8.1 10.0 8.4 GGE; particle size distribution was HDL. In addition, chemical composition times approximated Molar increases cholesteryl ester accompanied equimolar decreases cholesterol. low (LDL) prominent protein band 25.6 GGE. Active incubations resulted appearance additional bands 24.6 24.1 No morphological changes observed Chemical indicated LDL formed insufficient account lost, suggesting phospholipase activity occurred without concomitant esterification.