Leptin regulates STAT3 phosphorylation and SOCS3 expression in human lymphatic endothelial cells.

<p>Immunoblot analysis of pSTAT3 (Y705), STAT3 and SOCS3 in HDLECs exposed to 10 or 100 ng/ml leptin for 15 min (<b>A</b>) and 24 h (<b>B</b>). β-actin was used as a loading control. Histograms represent relative expression of pSTAT3 and SOCS3 proteins in HDLECs exposed to 10 or 100 ng/ml leptin for 15 min (<b>A</b>) and 24 h (<b>B</b>) as determined by densitometry analysis. Results are expressed as means ± SEM of four independent experiments; *<i>p</i> < 0.05, **<i>p</i> < 0.01, ***<i>p</i> < 0.001, <i>t</i>-test. n.s.: not significant. (<b>C</b>) Histograms represent total tube length in HDLECs exposed to leptin (100 ng/ml) for 17 h with or without 250 nM STAT3 inhibitor. Total tube length and mean length in each condition were measured using Image J software. Results are expressed as means ± SEM of four independent experiments; **<i>p</i> < 0.01, <i>t</i>-test. n.s.: not significant. (<b>D</b>) WST-8 assay showing proliferation of HDLECs treated with leptin (100 ng/ml) for 17 h with or without 250 nM STAT3 inhibitor. Histograms represent absorbance at 450 nm. Results are expressed as means ± SEM of four independent experiments; *<i>p</i> < 0.05, <i>t</i>-test. n.s.: not significant. (<b>C</b> and <b>D</b>) STAT3 inhibitor was added 30 min prior to leptin treatment.