Ox-LDL upregulates CRP expression through the IGF2 pathway in THP-1 macrophages.

Abstract

C-reactive protein (CRP) is an acute-phase reactant protein that not only plays a predictive role in determining atherogenesis risk but also represents an active participant in atherogenesis onset and progression. Moreover, an increasing number of studies have reported that oxidized low-density lipoprotein (Ox-LDL) plays a significant role in the initiation and progression of atherosclerosis. However, the effect and underlying mechanism of Ox-LDL on CRP expression remains unclear. THP-1 macrophages were treated with 0, 25, 50, or 100 μg/mL of Ox-LDL for 48 h, or 50 μg/mL of Ox-LDL for 0, 12, 24, and 48 h, respectively. Messenger RNA (mRNA) and protein levels were measured by real-time quantitative PCR and Western blot analysis, respectively. We found that Ox-LDL markedly increased insulin-like growth factor 2 (IGF2) and CRP mRNA and protein levels in a dose- and time-dependent manner in THP-1 macrophages. Treatment with Ox-LDL increased CRP protein expression, and this effect was completely abolished by siRNA-mediated silencing of IGF2 in THP-1 macrophages. Moreover, treatment with pcDNA3.1-IGF2 significantly enhanced CRP protein expression in Ox-LDL-stimulated THP-1 macrophages. CRP expression is upregulated by Ox-LDL through the IGF2 pathway in THP-1 macrophages.