Figure 3. Lp(a) Triggers Apoptosis in ER-Stressed Macrophages in a CD36-TLR2-Oxidative Stress-Dependent Manner.

(A–B) Macrophages from WT, Cd36^−/−, Tlr2^−/−, Tlr1^−/−, or Tlr6^−/− mice were incubated for 24 h with 0.5 μM thapsigargin alone or in combination with 25 μg/ml LDL or Lp(a), 50 μg/ml KOdia-PC, or 10 μg/ml LTA. (C) Apoptosis data for macrophages that were pre-incubated with or without 500 μM N-acetylcysteine (NAC) and then incubated for 24 h with thapsigargin alone or with 50 μg/ml of Lp(a). (D) Macrophages were incubated for 22 h with thapsigargin alone or in combination with 25 μg/ml apo(a) that was pre-treated in the absence (mock) or presence of trypsin and then assayed for apoptosis. The image shows a Coomassie-stained SDS-polyacrylamide electrophoresis gel of mock and trypsin-treated apo(a); for each condition, three different amounts of proteins were loaded per lane, increasing from left to right. (E) As in D, but here the apo(a) was treated with ± PLA₂ prior to trypsinization. *, p < 0.01 compared to other groups without the asterisk.