KLF2 is downregulated in PV and ET platelets and neutrophils by JAK-STAT signaling.KLF2 transcript levels were measured in (A) platelets and (B) neutrophils and expressed as a fold changes. KLF2 transcript levels in (C) platelets and (D) neutrophils correlated with JAK2V617F allele burden measured in neutrophils. (E) Phosphorylated STAT5 (P-STAT5) were measured in HEL cells treated with various concentrations of ruxolitinib by fluorescence activated cell sorting analysis and mean fluorescence intensity was calculated against samples without treatment which is taken as 1 and expressed as fold changes. (F) KLF2, (G) F3, and (H) SERPINE1 transcript levels were measured in HEL cells treated with various concentration of ruxolitinib. (I) KLF2 transcript levels were not correlated with F3 and SERPINE1 transcript levels in ruxolitinib treated HEL cells. (J) F3 transcript levels were measured in HEL cells with only KLF2 overexpression, only ruxolitinib treatment, and both KLF2 overexpression and ruxolitinib treatment. Expression levels were expressed as fold changes and no treatment control was taken as 1. P value was calculated by unpaired t test or paired t test. Correlation analysis was performed by Spearman correlation using GraphPad prism. ∗∗∗∗ P < .0001, ∗∗ P < .01, ∗ P < .05. P-STAT5, Phosphorylated STAT5; NT, no history of thrombosis; T, history of thrombosis.
