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Chemically modified low density lipoproteins as inducers of enzyme release from macrophages
Author(s) -
Hartung Hans-Peter,
Kladetzky Rudolf G.,
Hennerici Michael
Publication year - 1985
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(85)80710-9
Subject(s) - endocytosis , chemistry , elastase , enzyme , receptor mediated endocytosis , ldl receptor , biochemistry , cathepsin d , cathepsin g , intracellular , low density lipoprotein , receptor , lysosome , cathepsin , secretion , lipoprotein , cholesterol
Macrophages carry receptors on their surface for acetylated low density lipoprotein (ac‐LDL). Receptor‐mediated endocytosis of ac‐LDL is followed by intracellular cholesterol accumulation. We investigated whether occupation of these binding sites evokes the release of hydrolytic enzymes from mouse peritoneal macrophages cultured for up to 48 h. ac‐LDL at concentrations ranging from 25–250 was noted to promote in a dose‐dependent fashion secretion of the neutral proteinase elastase (EC 3.4.21.37) and the lysosomal acid hydrolases N ‐acetyl‐β‐glucosaminidase (EC 3.2.1.30), β‐glucuronidase (EC 3.2.1.31), β‐galactosidase (EC 3.2.1.23), α‐mannosidase (EC 3.2.1.24) and cathepsin D (EC 3.4.23.5). This stimulatory effect was non‐cytotoxic. LDL modified by treatment with malondialdehyde was also capable of augmenting enzyme liberation into culture supernates. These findings may have implications for some aspects of the atherosclerotic process.