LPA-mediated proliferation of hMCs. (A) Effect of development with LPA at the indicated concentrations on basal proliferation of cells at 3 (•) and 4 (○) weeks of culture in serum-free medium with SCF, IL-6, and IL-10. Thymidine incorporation is expressed as the mean ± half-range for 2 experiments. (B) Comitogenic effects of LPA on 3-week-old hMCs developed in the presence of LPA and transferred to fresh AIM V medium in the presence of SCF with LPA (5 μM) in the absence or presence of the indicated inhibitors. Results depicted are the mean ± SEM from 5 experiments. ^*P < .05.