Induction of stress proteins in mouse peritoneal macrophages by oxidized low-density lipoprotein.

The synthesis of 23-kDa and 34-kDa proteins in mouse peritoneal macrophages was enhanced when they were incubated with oxidatively modified low-density lipoprotein (LDL). This response required the oxidation of the lipid of the LDL, because native LDL had little effect and acetylated LDL enhanced the synthesis of 34-kDa protein only slightly. Since macrophages can bind and sequester oxidized LDL, they are subjected to an oxidative stress. The results suggest that the 34-kDa protein, which is identical with heme oxygenase, and the 23-kDa protein serve as stress protein that might afford protection against the oxidative stress.