Journal: Cell Death & Disease
Article Title: IRAK1 mediates TLR4-induced ABCA1 downregulation and lipid accumulation in VSMCs
doi: 10.1038/cddis.2015.212
Figure Lengend Snippet: IRAK1 was involved in the effects of TLR4 signaling on VSMCs lipid accumulation and ABCA1 expression in vitro . WT and TLR4 −/− VSMCs were incubated with or without 50 μ g/ml oxLDL for 24, 48 and 72 h. ( a and b ) Western blot was used to show IRAK1 and p-IRAK1 protein expression in oxLDL-treated or untreated VSMCs. Increased expression of p-IRAK1 protein was detected in oxLDL-treated WT VSMCs ( a , n =3 experiments in duplicate), but not in TLR4 −/− VSMCs ( b , n =3 experiments in duplicate). ( c ) IRAK1 kinase activity was significantly elevated in WT VSMCs stimulated with oxLDL, but significantly inhibited in TLR4 −/− VSMCs in response to oxLDL, as determined by an in vitro kinase assay ( n =2 experiments in duplicate). ( d – f ) WT VSMCs were transfected with IRAK1-specific siRNA using a transfection reagent. A non-related scrambled siRNA was used as a negative control (NC-siRNA). At 24 h following transfection, the cells were exposed to 50 μ g/ml oxLDL for 48 h. IRAK1 deficiency upregulated ABCA1 expression ( d , n =3 experiments in duplicate) and attenuated lipid accumulation in WT VSMCs as determined by BODIPY 493/503 staining ( e , green fluorescence, scale bar=20 μ m). Quantification of lipid accumulation was based on the OD values for destained Oil Red O in WT VSMCs ( f , n =4 experiments in duplicate). All data are represented as the fold change relative to the controls and are expressed as the mean±S.E.M. * P <0.05, ** P <0.01 compared with the untreated control group
Article Snippet: Following this, the membranes were incubated with primary antibodies against TLR4, ABCA1 (Abcam, Burlingame, CA, USA), IRAK1 (Santa Cruz Biotechnology) or p-IRAK1 (phospho-Thr387, Biorbyt, Cambridge, UK).
Techniques: Expressing, In Vitro, Incubation, Western Blot, Activity Assay, Kinase Assay, Transfection, Negative Control, Staining, Fluorescence, Control