Fig. 10.

Potent paracrine promitogenic effects of dR-conditioned medium are due, in part, to PDGFs, SDF-1, and S100A4. A: paracrine promitogenic effect of dR cell-conditioned medium (R-CM) on target dS-SMC (gray bar) is partially attenuated by neutralizing PDGF-BB/AB antibodies (10 ng/ml). Serum-free medium conditioned by control adventitial fibroblasts (Fib-CM) had minimal promitogenic effect on S-SMC. The data are presented as the ratio of BrdU-positive cell nuclei vs. total nuclei number. **P < 0.001 compared with 0.2% PDS; #P < 0.05 compared with the effect of R-CM without PDGF antibodies. B: paracrine promitogenic effect of R-CM on target dS-SMC (gray bar) is partially attenuated by neutralizing SDF-1/CXCL12 antibodies (added at 3, 6, 12 ng/ml) in a dose-dependent manner. **P < 0.001 compared with 0.2% PDS; #P < 0.05 and ##P < 0.005 compared with the effect of R-CM without SDF-1 antibodies. PDGF-BB (10 ng/ml)-stimulated BrdU incorporation in target dS-SMC is not affected by SDF-1 neutralizing antibodies (12 ng/ml). ***P < 0.0001 compared with 0.2% PDS. C: R-CM-induced proliferation of target S-SMC (gray bar) is inhibited by incubation with S100A4-antibodies (1.25 μg/ml). Specificity of the effect was tested by adding human recombinant S100A4 (rS100A4, 2.5 μg/ml), which also exhibited promitogenic effect on S-SMC, and this effect was inhibited by S100A4 antibodies. PDGF-BB (10 ng/ml)-stimulated proliferation of target dS-SMC was not affected by S100A4 antibodies. Cell counts were done on day 5. The data are expressed as fold-increase in cell numbers compared with untreated (0.2% PDS) cells. ***P < 0.0001 compared with 0.2% PDS; *P < 0.05 compared with 0.2% PDS; ##P < 0.005 compared with R-CM-treated cells; #P < 0.05 compared with rS100A4-treated cells. Gray and open bars, untreated cells; closed bars, antibody-treated cells. For all experiments, cells growing in 4 wells were analyzed for each data point.