Sukhova, GalinaShi, Guo-PingSimon, D IChapman, H ALibby, Peter2014-12-121998Sukhova, G K, G P Shi, D I Simon, H A Chapman, and P Libby. 1998. “Expression of the Elastolytic Cathepsins S and K in Human Atheroma and Regulation of Their Production in Smooth Muscle Cells.” J. Clin. Invest. 102 (3) (August 1): 576–583. doi:10.1172/jci181. http://dx.doi.org/10.1172/JCI181.0021-9738http://nrs.harvard.edu/urn-3:HUL.InstRepos:13506487Formation of the atherosclerotic intima must involve altered metabolism of the elastin-rich arterial extracellular matrix. Proteases potentially involved in these processes remain unclear. This study examined the expression of the potent elastases cathepsins S and K in human atheroma. Normal arteries contained little or no cathepsin K or S. In contrast, macrophages in atheroma contained abundant immunoreactive cathepsins K and S. Intimal smooth muscle cells (SMC), especially cells appearing to traverse the internal elastic laminae, also contained these enzymes. Extracts of atheromatous tissues had approximately twofold greater elastase-specific activity than extracts of uninvolved arteries, mostly due to cysteine proteases. Cultured human SMC displayed no immunoreactive cathepsins K and S and exhibited little or no elastolytic activity when incubated with insoluble elastin. SMC stimulated with the atheroma-associated cytokines IL-1beta or IFN-gamma secreted active cathepsin S and degraded substantial insoluble elastin (15-20 microg/10(6) cells/24 h). A selective inhibitor of cathepsin S blocked > 80% of this elastolytic activity. The presence of cathepsins K and S at sites of vascular matrix remodeling and the ability of SMC and macrophages to use these enzymes to degrade elastin supports a role for elastolytic cathepsins in vessel wall remodeling and identifies novel therapeutic targets in regulating plaque stability.en-USatherosclerosiscysteine proteasesmooth muscle cellelastolytic activityJournal Article2014-12-1210.1172/JCI181