Fig. 2.

The effect of HDL on OxPAPC signaling is not mediated by SR-BI. HAECs were transfected with either siRNA targeting SR-BI or scramble control siRNA and treated 48 h later with media, OxPAPC (50 μg/ml), HDL (50 μg/ml), or OxPAPC and HDL (50 μg/ml) as described in the Materials and Methods. The mRNA expression levels of KLF2, ATF3, INSIG1, IL8, and HO1 were determined by qPCR and normalized to GAPDH expression levels. All data are presented as average log2-fold change of triplicates ± SEM. Asterisks indicate significance level in unpaired Student’s t-test (*P < 0.05, **P < 0.01, ***P < 0.001) A: Despite effective silencing of SR-BI, the expression patterns of KLF2, ATF3, LDLR, and IL-8 after OxPAPC or OxPAPC+HDL treatment were unchanged. Results were confirmed using two separate siRNAs. B: Similarly, blocking of SR-BI using SR-BI antiserum (1:300 dilution) had no effect on the HDL response of KLF2, ATF3, LDLR, or IL-8. Rabbit IgG was used as control. C: HAECs were either untreated or treated with OxPAPC (50 μg/ml) in the presence or absence of HDL (50 μg/ml) or delipidated apoA1 (25–50 μg/ml). HDL and apoA1 were added for 1 h of pretreatment and 4 h of cotreatment. The mRNA expression levels of KLF2, ATF3, INSIG1, IL-8, and HO1 were determined by qPCR and normalized to GAPDH expression levels.