Coculture with adipocyte-differentiated MSCs stimulates the phosphorylation of STAT3 and MAPK. NB4 cells (A), ZnSO₄ pretreated PR9 cells (200 μM, 24 hours) (B), and untreated PR9 cells (C) were cultured alone (control) or cocultured with undifferentiated MSCs or adipocyte-differentiated MSCs at the indicated conditions (with or without chimeric blocking OB-R or MAPK inhibitor) for 24 hours. Clarified lysates were probed with antibodies to phospho-MAPK, ERK2, STAT3, Tyr-705 phospho-Ab, STAT3, and β-actin by Western blotting. Results shown are representative of 3 experiments.