Participation of proteoglycans in PF4-mediated inhibition of LDL degradation.

Degradation of ¹²⁵I-LDL (5 nM) in the presence or absence of PF4 (20 μg/mL) by WT CHO cells and CHO cells that do not express heparan sulfate (HS⁻). LDL-R–transfected cells were pretreated with buffer (B), heparanase (H), chondroitinase ABC (C), or both heparanase and chondroitinase (HC) for 2 hours at 37°C prior to addition of ¹²⁵I-LDL. Data are expressed relative to “control” (Ct), which represents degradation of LDL in the absence of PF4. Data are the mean ± SEM of 3 independent experiments, each performed in triplicate.