Effects of angiotensin II on expression of lectin-like oxidized low-density lipoprotein receptor-1 in cultured THP-1 cells

AIM: Cross talk between oxidized low-density lipoprotein (ox-LDL) and angiotensin II(Ang-Ⅱ) may play an important role in the pathogenesis of atherosclerosis. In this study, we tested the hypothesis that AngⅡ can induce expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), a new receptor for ox-LDL, in cultured THP-1 cells. METHODS: Cultured THP-1 cells were treated with 0.1 μmol/L PMA for 48 hours at first .Then the cells were incubated with 10 -9 -10 -5 mol/L Ang II for 24 hours, or with 10 -6 mol/L Ang II for various time up to 48 hours. LOX-1 protein expression was examined by cell enzyme linked immunosorbent assay (ELISA), and LOX-1 mRNA was detected by quantitative competitive reverse transcription-polymerase chain reaction (RT-PCR) . RESULTS: PMA-untreated THP-1 cells didn't express LOX-1 mRNA. After 48 h of PMA treatment, THP-1 cells differentiated and LOX-1 mRNA was detected. Incubation of AngII with THP-1 cells for 24 h significantly increased LOX-1 mRNA and protein expression in a concentration-dependent manner (10 -9 -10 -5 mol/L, P0.05 ). Otherwise , after treatment with 1×10 -6 mol/L Ang II for 3 hours, LOX-1 protein and mRNA expression were elevated ( P 0.05), reaching the maximum at 24 hours, then it declined. CONCLUSIONS: PMA induces differentiation and LOX-1 mRNA expression in THP-1 cells. Ang II upregulates LOX-1 expression in a concentration-dependent and time-dependent manner, and this effect of Ang II may contribute to the pathogenesis of atherosclerosis.