FIG. 6.

Cytokine-induced downregulation of LRP1 is not mediated by proteasome degradation. A, MVECs were exposed to copper, IL-1β, IL-6 or TNFα in the presence or absence of proteasome inhibitors, MG-132 (0.5 µM, A) or lactacystin (5 µM, B), for 24 h, and the steady-state levels of LRP1 were measured. The graph represents mean ± S.E.M. of 3 separate experiments (n = 8–11). *P < 0.05 compared to the group without proteasome inhibitor. C, MVECs were exposed to copper, IL-1β, IL-6 or TNFα in the presence or absence of a lysosomal inhibitor, CHQ, for 24 h, and the steady-state levels of LRP1 were measured. The graph represents mean ± S.E.M. of 3 separate experiments in duplicates (n = 6). No significance was observed.