Toll-Like Receptor 4 Mediated Oxidized Low-Density Lipoprotein-Induced Foam Cell Formation in Vascular Smooth Muscle Cells via Src and Sirt1/3 Pathway

Figure 4

Knockdown of Tlr4 suppressed oxLDL-induced lipid accumulation, ROS and mitochondrial superoxide production, and regulated related gene activation and expression. Tlr4 was knockdown by siRNA transfection within VSMCs. (a) The Tlr4-specific [Tlr4(-)] and negative (NC) siRNA were transfected into VSMCs for 72 hours, and the knockdown efficiency was detected. ( per group, results were expressed as ; compared with the NC group by Student’s -test, .) Tlr4(-) or NC VSMCs were treated with or without oxLDL (50 μg/mL) for 48 hours. (b) Lipid accumulation (Nile red stain, orange). (c) ROS (DCFH-DA, green) and (d) mitochondrial superoxide (MitoSOX, red) were measured. ( per group, results are expressed as ; , , as compared with oxLDL-untreated NC group; ^#, ^##, as compared with oxLDL-treated NC group.) (e) Tlr4(-) or NC VSMCs were treated with or without oxLDL (50 μg/mL) for 48 hours; western blot was conducted to measure oxidative stress-associated genes, VSMC contractile phenotype markers (Myh11 and αSma), and foam cell markers (Mac2 and Cd68). And β-actin served as an internal reference gene to normalize protein expression. (f) All the western blot results were calculated using grayscale value. ( per group, results are expressed as ; , , as compared with oxLDL-untreated NC group; ^#, ^##, as compared with oxLDL-treated NC group).

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