Abstract 207: Differential Regulation of Monocyte/Macrophage Atherogenic Properties by Adiponectin: Role of Macrophage Polarization and Adiponectin Receptors
Adiponectin, an adipocytokine produced by the adipose tissue, exerts metabolic, anti-inflammatory and anti-atherogenic effects to ameliorate diabetes and cardiovascular disease and is a potentially important therapeutic target. However, mechanisms of adiponectin vascular actions and the regulation of macrophage adiponectin receptor expression under inflammatory/atherogenic activation remain unclear. Our studies with human monocytes/macrophages revealed differential adiponectin receptor regulation in subjects with insulin-resistance. Here, we investigated adiponectin regulation of macrophage gene expression under pro- and anti-inflammatory conditions. We addressed the hypothesis that differential activation of macrophages into the classical (M1) or alternative (M2) program alters their adiponectin receptor (AdipoR1 and AdipoR2) expression. The microarray gene expression analyses in human monocytes exposed to TNF-α showed that adiponectin inhibited several inflammatory/atherogenic genes. Our studies revealed that adiponectin itself induces AdipoR1 and AdipoR2 expression in macrophages. We further investigated the effects of macrophage polarization (M1 or M2) on adiponectin receptor expression in bone marrow-derived and peritoneal macrophages. These studies demonstrated that M1 activation (IFN-γ and LPS) significantly reduced AdipoR1 and AdipoR2 expression. In contrast, M2 activation of (IL-4 or IL-10) maintains a significantly higher level of AdipoR1 and AdipoR2. In M2 activation, adiponectin receptor expression was more substantial in IL-10 than IL-4-polarized macrophages. These results provide important evidence that macrophage polarization profoundly alters their adiponectin receptor expression and thus functional responses to adiponectin. Thus, adiponectin-mediated macrophage functions are regulated by adiponectin receptor expression which is modulated by the macrophage polarization which controls their inflammatory and atherogenic properties.
- © 2012 by American Heart Association, Inc.