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. Author manuscript; available in PMC: 2009 Feb 1.
Published in final edited form as: Free Radic Biol Med. 2007 Aug 24;44(3):284–298. doi: 10.1016/j.freeradbiomed.2007.08.012

Figure 7. Hemin blocks IL-18-mediated EC death via HO-1 induction.

Figure 7

A, Hemin induces HO-1 expression. Quiescent EC were treated with hemin (10 µM). Cells were harvested at the indicated time periods, and analyzed for HO-1 mRNA expression by RT-qPCR (n=6). B, HO-1 knockdown blocks hemin-mediated rescue of IL-18-dependent EC death. EC were treated with HO-1 siRNA for 48 h, and then treated with hemin and IL-18 for an additional 24 h. Cell death was analyzed by Annexin V-FITC/PI staining and flow cytometry (n=6). C, HO-1 knockdown is confirmed by Western blotting (n=3). EC treated as in C were analyzed for HO-1 knockdown by Western blotting at 48 h post-HO-1 siRNA treatment. siRNA that does not target any gene in the mammalian genome served as a control. D, Hemoglobin (Hg) reverses hemin-mediated rescue of IL-18-depndent EC death. Quiescent EC were treated with hemin and Hg prior to IL-18 addition. After 24 h, cell death was analyzed by Annexin V-FITC/PI staining and flow cytometry (n=6). A, *p<0.01, **p<0.001 Vs. Untreated; B, *p<0.001 Vs. Untreated, †p<0.01 Vs. IL-18 alone; D, *p<0.001 Vs. Untreated, †p<0.01 Vs. IL-18.