Figure 5.

The effect of substrate stiffness on F-actin structures and CSK elastic modulus (in Pa) is shown in (a) for AECs and (b) for AMs. Three type I collagen coated substrates of different stiffness values were tested, i.e., successively from left to right in (a and b): plastic/glass substrate (E_s [Young modulus] ≥3 MPa; stiff gel [E_s = 58 kPa]; soft gel [E_s = 23 kPa]). Images in (a, 1–6) provide for AECs and (b, 1–6) for AMs, 3D visualizations of F-actin structure from cumulated images of confocal planes viewed from top (a, 1–3 and b, 1–3) and from the side (a, 4–6 and b, 4–6). Graphs on bottom of (a and b) represent respectively the elastic modulus (in Pa) of confluent AECs (measured through RGD coated ferromagnetic beads by MTC) and resting AMs (measured through RGD coated silicate beads by OT) plotted for the three different substrates tested. Note that different scales are used in (a and b). Values are expressed as mean ± SE. Each value is the mean of three independent measurements. The statistical test used is the ANOVA test. No significant differences were observed in AECs.