Abstract
Objective: The cysteine protease, legumain, is thought to have a role in the processing and activation of proteases such as cathepsin-L, which have been implicated in plaque rupture. This study aimed to determine: if legumain activity is up-regulated in unstable areas of plaque; the effect of legumain overexpression on the activity of cathepsin-L and the effect of mutation of the legumain RGD sequence on its cellular location.
Methods and results: Legumain was measured in human carotid plaque extracts (n = 17) using a novel ELISA and modified activity assay. Unstable regions of plaque contained more than twice the amount of legumain protein (P < 0.001) and activity (P < 0.03) compared with stable regions of the same plaque. Overexpression of legumain in THP-1 macrophages using an adenoviral construct resulted in the processing of cathepsin-L from its 30 kDa to its 25 kDa form compared with controls.
Conclusion: Unstable regions of plaque contain increased levels of active legumain. Over-expression of legumain in macrophages alters intracellular processing of cathepsin-L to its mature 25 kDa form. This may be a means by which legumain could contribute to plaque instability. (C) 2009 Elsevier Ireland Ltd. All rights reserved.
Original language | English |
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Pages (from-to) | 83-89 |
Number of pages | 7 |
Journal | Atherosclerosis |
Volume | 208 |
Issue number | 1 |
DOIs | |
Publication status | Published - Jan 2010 |
Keywords
- Atherosclerosis
- Carotid artery
- Macrophages
- Proteases
- RGD
- ASPARAGINYL ENDOPEPTIDASE
- ATHEROSCLEROTIC PLAQUES
- MAMMALIAN LEGUMAIN
- MACROPHAGES
- CELLS
- MICE
- ELECTROPHORESIS
- PROTEINASES
- DEGRADATION
- ACTIVATION