Low density lipoprotein activates monocytes to express tumor necrosis factor

Publisher Website
Google Scholar
Abstract
We analyzed the effect of acetylated low density lipoprotein (aLDL) incubation on tumor necrosis factor (TNF) mRNA and protein expression in isolated resting human monocytes in serum free DMEM. TNF mRNA expression was about one third that of PMA and was dose dependent. The maximum stimulatory effect on TNF mRNA was at 250 μg/ml, while 500 μg/ml induced downregulation. The maximum stimulatory effect occurred at 6 hours, and by 24 hours TNF mRNA expression returned to the resting state. Acetyl LDL also induced the expression ofimmunoreactive TNF, reaching a sevenfold maximum above control at 12 hours following a 6 hour exposure period. The results suggest that aLDL is a potent stimulator of TNF expression in resting monocytes. This mechanism may be operational in atheroma evolution.