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. Author manuscript; available in PMC: 2011 Jul 25.
Published in final edited form as: J Thromb Haemost. 2009 Oct 23;8(1):185–193. doi: 10.1111/j.1538-7836.2009.03662.x

Figure 4. MMP-2 activity and expression is selectively required for EPC differentiation in response to VEGF stimulation.

Figure 4

(A) EPCs were cultured in 3D collagen gel for 48 hours in the presence o f 25 ng/mL VEGF plus specific MMP-2 inhibitor (444244) at the indicated concentrations. As described in the Methods, the sum of the tube length in six digital images per well was indicated as micrometer per square millimeter. Results are given as percentage of tube length/area compared with the control (0 μM) (which was set as 100%). Experiments were done in triplicates. * p< 0.05; ** p<0.01. (B) Gene silencing of MMP-2 (i) and MMP-9 (ii). The knockdown efficiency by siRNA was evaluated by RT-PCR. Lane 1, control non-silencing siRNA, lane 2, MMP-2 or MMP-9 siRNA. (C) After transfection with siRNA, EPCs in 3D collagen gel were cultured with VEGF for 48 and 72 hours, respectively. Experiments at each time point were done in triplicates. Quantitation of tube length was done as described in A. Results are given as percentage of tube length/area compared with the control group at 48 hours (which was set as 100%). *p<0.0001; n.s: not significant, compared with control.