Fig. 1.

SAA-stimulated VSMC-secreted matrix proteoglycans from apoe^−/− mice had increased LDL binding, which was dramatically reduced when TGF-β was inhibited. VSMCs were treated with vehicle, SAA, or TGF-β for 24 h, then washed and incubated with Alexa-594-labeled LDL for 2 h. SAA- and TGF-β-treated cells had increased LDL binding compared with vehicle treatment. To determine the necessity of TGF-β in SAA-mediated LDL retention, VSMCs were treated with SAA and either the TGF-β-neutralizing antibody 1D11 or control antibody 13C4. The 1D11 prevented the SAA increase in LDL binding; there was no effect of 13C4. To determine the role of proteoglycans in the SAA-mediated LDL binding, cells were treated with sodium chlorate, which prevents sulfation of proteoglycan glycosaminoglycan side chains. Sodium chlorate prevented both the SAA- and TGF-β-dependent increase in LDL binding. LDL binding is expressed as Alexa-fluor 594 surface area normalized to DAPI surface area quantified by fluorescent microscopy using ImageJ software (NIH). Data are presented as mean ± SEM from 5 to 10 20× regions/condition. * P < 0.001.