Figure 2.

RasGrf1 expression is elevated in fibroblasts derived from old MSCs. A). Ras activation as measured in quiescent fibroblasts derived from young and old MSCs. Results were normalized to protein content of cell lysates. B and C) Increased expression of RasGrf1 mRNA in fibroblasts derived from old MSCs (B) or old hearts (as the whole-heart lysate) (C) as measured by quantitative PCR. Young and old signifies cells derived from 3- and 30-mo-old mice, respectively. P < 0.05 denotes statistical significance; the number in each column corresponds to the number of donor animals from which cells were derived.