Figure 4.

An HSP90 inhibitor inhibited leptin‐induced activation of STAT3 in neuronal cells. (A) SH‐SY5Y‐Ob‐Rb cells were treated with the HSP90 inhibitor, geldanamycin (GA: 0.1–10 μM), and leptin (0.5 μg·mL⁻¹)‐induced STAT3 phosphorylation was analysed. The HSP90 inhibitor inhibited leptin‐induced STAT3 phosphorylation. Dunnett's test was performed to compare control cells treated with leptin (defined as control group of Dunnett's test) and other groups. *P < 0.05 versus control cells treated with leptin. n = 5. (B) STAT3 phosphorylation induced by a lower dosage of leptin (0.03 μg·mL⁻¹) was attenuated by the HSP90 inhibitor, geldanamycin (GA: 10 μM), in SH‐SY5Y‐Ob‐Rb cells. *P < 0.05 versus control cells treated with leptin. Student's t‐test. n = 5. (C) Ob‐Rb transfected GT1–7 cells were treated with the HSP90 inhibitor, geldanamycin (GA: 10 μM), and leptin (0.1 μg·mL⁻¹, 15 min)‐induced STAT3 phosphorylation was analysed. The HSP90 inhibitor inhibited leptin‐induced STAT3 phosphorylation. Each set of data was expressed as fold increase over control cells. *P < 0.05 versus control cells treated with leptin. Student's t‐test. n = 5.