Abstract 4136905: EF-24, a curcumin analog, reverses interleukin-18-induced miR-30b or miR-342-dependent TRAF3IP2 expression, RECK suppression, and the proinflammatory phenotype of human aortic smooth muscle cells

Curcumin, a polyphenolic compound derived from the widely used spice Curcuma longa, has shown anti-atherosclerotic effects in cultured vascular cells and animal models. We previously reported that the induction of the proinflammatory molecule TRAF3IP2 (TRAF3 Interacting protein 2) or inhibition of the matrix metalloproteinase (MMP) regulator RECK (Reversion Inducing Cysteine Rich Protein with Kazal Motifs) contributes to agonist-induced proinflammatory, pro-oxidant, pro-mitogenic and pro-migratory effects in vascular smooth muscle cells. Here we hypothesized that, EF-24 ((3E,5E)-3,5-bis[2-fluorophenyl (methylene]-4piperidinone), a curcumin analog with better bioavailability and potency, reverses interleukin (IL)-18-induced TRAF3IP2 induction, RECK suppression and the proinflammatory phenotype of primary human aortic smooth muscle cells (ASMC). Exposure to recombinant human IL-18 (10 ng/ml) induced TRAF3IP2 mRNA and protein expression, but markedly suppressed RECK in a time-dependent manner. Further investigations revealed that IL-18 induced miR-30b, but suppressed miR-342, in a p38 MAPK and JNK-dependent manner. While miR-30b inhibitor blunted IL-18-induced TRAF3IP2 expression, miR-30b inhibitor and miR-342 mimic each restored RECK expression. Further, IL-18 induced ASMC migration (Boyden chamber assay) and proliferation (CyQUANT Cell Proliferation assay), and these effects were reversed by TRAF3IP2 knockdown or RECK overexpression. Our results also show that IL-18 induced MMP2 and MMP9 expression and activity, and targeting their expression inhibited IL-18-induced ASMC migration. TRAF3IP2 knockdown or RECK overexpression also reversed IL-18-induced ASMC proinflammatory phenotype switching as evidenced by the enhanced expression of the SMC markers ACTA2 and MYH11, and reduced expression of the proinflammatory markers Galectin 3, Olr1, VCAM, CCL2, IL-6, IL-8, and TNF-α. Importantly, preincubation with EF-24 markedly suppressed IL-18-induced SMC proliferation, MMP expression, migration and the proinflammatory phenotype switching. Together, these results suggest that the curcumin analog EF-24 has therapeutic potential in vascular inflammatory and proliferative diseases, including atherosclerosis, by differentially regulating TRAF3IP2 and RECK in vascular SMC.