Fig. 7

Effects of activating agents on secreted cathepsin S protease activity in macrophage and microglia cell lines. Cells were treated with various doses of LPS, or with 10 nM PMA, 20 ng/ml TNF-α, 50 U/ml IFN-γ, 20 ng/ml IL-1α, 50 U/ml IFN-α, or 10 ng/ml GM-CSF for 24 hr in MSFM. Cathepsin S protease activity was measured in the conditioned medium of RAW macrophages (A and C) or N13 microglia (B and D) from 24-hr-treated cells utilizing the fluorogenic substrate Z-FR-AMC as described in Materials and Methods. Data represent mean ± SEM of three experiments measuring E64-inhibitable cathepsin S activity. Activity in the absence of LPS treatment is taken as control (100%).