Fig. 4

Exogenous TG2 affects astrocyte-derived fibronectin deposition and cross-linking. Primary rat astrocytes were plated on laminin coated plastic and double immunocytochemical surface stainings detected fibronectin (FN, red) and TG2 (green) in untreated control astrocytes (CTRL) and in astrocytes that were treated with exogenous TG2 (0.13 or 1.3 μM) for 48 h (a, b, and c). Exogenous TG2 resulted in morphologically altered fibronectin deposition (indicated by arrows in c). Representative images of three independent experiments are shown. Scale bar represents 20 μm. Fibronectin (FN) aggregates on laminin (LAM) coated plastic were studied after removal of untreated astrocytes that were allowed to produce extracellular matrix for 48 h. The extracellular matrix was incubated with exogenous TG2 (0.64 μM, 16 h) and pre-incubated with the specific TG2 inhibitor Z-DON (1 μM) for 30 min at 37 °C (d). Representative blots of four independent experiments are shown. Each bar represents the mean + standard error of the mean of signal intensities from blots of four separate experiments that were calculated as average percentage compared to control (*P < 0.05 and ***P < 0.001)