PMID: 2508645Sep 1, 1989Paper

Macrophages possess both neutral and acidic protease activities toward low density lipoproteins

Atherosclerosis
S M RankinD S Leake

Abstract

Low density lipoproteins (LDL) have been strongly implicated in the pathogenesis of atherosclerosis. We have studied the proteolytic degradation of these lipoproteins by macrophages, which are a major cellular constituent of atherosclerotic lesions. Mouse peritoneal macrophages contained both an acidic and a less active but distinct neutral/alkaline protease activity toward human 125I-labelled LDL. The acidic activity had a pH optimum of 4.5 and the neutral/alkaline activity one of 8-8.5. The acidic activity started to plateau with increasing lipoprotein concentrations whereas the neutral activity was directly proportional to the lipoprotein concentration up to at least 150 micrograms of protein/ml. The acidic protease activity had a complex time course whereas the neutral activity was directly proportional to the time of incubation up to at least 48 h. Leupeptin (35 microM) and pepstatin (5 microM) inhibited the acidic activity by about 70% individually and almost entirely in combination, indicating that cathepsins B and D are important in the degradation of LDL by lysosomal cathepsins. In contrast, there was little, if any, inhibition of the neutral protease activity by leupeptin or pepstatin. The acidic protease activity was...Continue Reading

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Citations

Jan 7, 1993·Biochemical Pharmacology·S M RankinD S Leake
Jan 1, 1994·Chemistry and Physics of Lipids·M PursiainenC Ehnholm
Jan 1, 1991·Progress in Lipid Research·E KorenR D Fugate
Nov 1, 1993·FEBS Letters·J Morgan, D S Leake
Jun 1, 1990·Biochemical Pharmacology·C V de WhalleyD S Leake
Jul 20, 2011·Biochimica Et Biophysica Acta·Sabrina MüllerThomas Reinheckel
Sep 1, 1993·Scandinavian Journal of Gastroenterology·R GoyalK Singh

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