Although recent studies have reported cardioprotective effects of C1q/TNF-related protein 9 (CTRP9), the closet adiponectin paralog, its role on cytokine-induced endothelial inflammation is unknown. We investigated whether CTRP9 prevented inflammatory cytokine-induced nuclear factor-kappa B (NF-êB) activation and inhibited the expression of adhesion molecules and a chemokine in the vascular endothelial cell. We used human aortic endothelial cells (HAECs) to examine the effects of CTRP9 on NF-êB activation and the expression of NF-êB-mediated genes, including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and monocyte chemoattractant protein-1 (MCP-1). Tumor necrosis factor alpha (TNFá) was used as a representative proinflammatory cytokine. In an adhesion assay using THP-1 cells, CTRP9 reduced TNFá-induced adhesion of monocytes to HAECs. Treatment with CTRP9 significantly decreased TNFá-induced activation of NF-êB, as well as the expression of ICAM-1, VCAM-1, and MCP-1. In addition, treatment with CTRP9 significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC), the downstream target of AMPK. The inhibitory effect of CTRP9 on the expression of ICAM-1, VCAM-1, and MCP-1 and monocyte adhesion to HAECs was abolished after transfection with an AMPKá1-specific siRNA. Our study is the first to demonstrate that CTRP9 attenuates cytokine-induced vascular inflammation in endothelial cells mediated by AMPK activation.
AMP-Activated Protein Kinases Adiponectin