Figure 5.

Endothelial transcriptional programs evoked by atheroprotective flow require KLF2 expression. (A) Effects of suppressing flow-dependent KLF2 upregulation on gene expression. Cells were treated with either scrambled siRNA or siRNA targeting KLF2 for 24 hours and then placed under static or atheroprotective conditions for an additional 24 hours. Shown are RT-PCR data for the indicated genes. hPGT, human prostaglandin transporter; NOV, nephroblastoma overexpressed gene. (B) Monitoring of the interferon response in HUVECs treated with control or KLF2 siRNAs. Gene expression of 2′-5′-oligoadenylate synthetase (OAS2) or interferon-inducible transmembrane protein 1 (IFITM1) was assessed by TaqMan RT-PCR. As a positive control for the interferon response, HUVECs were incubated with long double-stranded RNA (dsRNA) poly I:C for 24 hours (n = 3). (C) Western blot for proteins in the same samples as represented in A. (D) Surface TM FACS on HUVECs under the indicated conditions. (E) ELISA of CNP from supernatants under the conditions described in A. (F) 15-d-PGJ2 levels in supernatants under the indicated conditions. (G) Histogram (blue bars) of genes binned according to fold regulation under flow. Overlaid on the histogram is a graph showing the percentage of genes within each bin that are KLF2 dependent (red diamonds and trend line). Gray shading indicates the portion of the histogram representing the 74 most highly regulated genes under flow (see text). All data are expressed as mean ± SEM (n = 3). *P < 0.05, **P < 0.01 vs. control; Student’s t test.