STAT3 KO bEnd5 endothelial cells were transfected with GFP-containing constructs and treated with TM for 72 h. Top panels are
bright-field images. Bottom images are fluorescent images. A) With control transfections (GFP alone, CON TM), many
transfected cells show aberrant small rounded morphology (yellow arrows). B) WT-STAT3-GFP cells looked for the most
part healthy, i.e., long-flattened attached cells (white arrows). C) S727A mutants were mostly rounded, whereas
D) S727D mutants looked healthy. E) Significantly more GFP+ cells survived TM treatment when
overexpressing GFP-WT STAT3 relative to control plasmids. The number of cells transfected with S727A mutants was significantly
lower than the WT and S727D mutant transfected cells. Cell counts performed at 72 h are representative of 4 independent
experiments, normalized to transfection efficiency obtained at 24 h. * p<0.05 compared to control. #
p<0.05, ## p<0.01 compared to S727A.