Oxidized LDL enhances pro-inflammatory responses of alternatively activated M2 macrophages: A crucial role for Krüppel-like factor 2

We show that (1) anti-inflammatory M2 macrophages are more susceptible to foam cell formation than pro-inflammatory M1 macrophages, (2) exposure to oxidized LDL renders M2 macrophages pro-inflammatory, and (3) Krüppel-like factor 2 is involved in the enhanced secretion of MCP-1 by M2 macrophages loaded with oxidized LDL. The phenotype switch of M2 macrophages from an anti- to a pro-inflammatory profile may play an important role in pathogenesis of atherosclerosis, and could represent a novel therapeutic target.