Figure 2.

Cellular and secreted cathepsin L activities and extracellular matrix (ECM) exposure. Murine primary cerebral endothelium, astrocytes, and microglia grown on various ECM substrates under normoxia (open bars) and oxygen-glucose deprivation (OGD) (filled bars). Substrates were poly-D-lysine (PDL), laminin (LN), collagen type IV (COL IV), fibronectin (FN), and vitronectin (VN). Cathepsin L activities of cell lysates and conditioned media were determined based on standard curves of the activity of purified cathepsin L from human liver, and reported as relative cathepsin L activity per protein content (mU/μg protein). Only microglia displayed significant secretion of cathepsin L under normoxia and OGD at neutral pH. Data are mean activity±s.d. (n=6 samples per condition in endothelium; n=9 samples per condition in astrocyte and microglia cells).