Adiponectin as an anti-inflammatory factor

Abstract

Obesity is characterized by low-grade systemic inflammation. Adiponectin is an adipose tissue-derived hormone, which is downregulated in obesity. Adiponectin displays protective actions on the development of various obesity-linked diseases. Several clinical studies demonstrate the inverse relationship between plasma adiponectin levels and several inflammatory markers including C-reactive protein. Adiponectin attenuates inflammatory responses to multiple stimuli by modulating signaling pathways in a variety of cell types. The anti-inflammatory properties of adiponectin may be a major component of its beneficial effects on cardiovascular and metabolic disorders including atherosclerosis and insulin resistance. In this review, we focus on the role of adiponectin in regulation of inflammatory response and discuss its potential as an anti-inflammatory marker.

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Adiponectin-mediated regulation of inflammatory responses in different cell types. Adiponectin negatively regulates CRP and TNF-α expression in adipose tissue, whereas adiponectin expression is inhibited by TNF-α and IL-6. Adiponectin inhibits IL-8, VCAM-1 and ROS production in endothelial cells through cAMP-PKA-dependent signaling. Adiponectin also stimulates AMPK activation in endothelial cells, leading to activation of eNOS. Adiponectin suppresses TNF-α production in cardiac cells through its ability to stimulate the COX-2-PGE2 pathway. In macrophages, adiponectin attenuates TNF-α and IL-6 production through its ability to suppress NF-κB activation, and enhances IL-10 expression resulting in increase in TIMP-1 production. Adiponectin inhibits foam cell formation by reducing SR-A expression.