FIG. 2.

Increased mitogen-activated protein kinase (MAPK) activation in OA hMSCs as compared with normal hMSCs. MSCs isolated from bone marrow aspirates of OA human donors undergoing total hip anthroplasty and normal human MSCs (Lonza) were cultured in complete DMEM to near confluence. Then, the cells were serum starved for 24 h. The protein expression and phosphorylation of MAPKs (ERK, JNK, and p38) in MSC lysates were determined by immunoblotting. Values represent the mean±SE of seven donors (A: pERK1/2, 307±69, ***p<0.001; B: pJNK, 943±92, ****p<0.0001; and C: p-p38, 132±19, *p<0.05) as percentage of normal human MSCs (100%). ERK, extracellular signal-regulated kinase; JNK, c-Jun N-terminal kinase.