THE INFLUENCE OF ADIPONECTIN ON PRODUCTION OF APOLIPOPROTEINS A-1 AND E BY HUMAN MACROPHAGES
Adiponectin is an adipose tissue hormone, affecting energy and lipoprotein metabolism and modulating inflammatory responses. However, the role of this adipokine in atherogenesis remains poorly understood. The aim of this study was to investigate the effect of adiponectin on production of apolipoproteins (apo) A-1 and E by human macrophages (MΦ). The study was conducted on macrophage-like cells of THP-1 cell line of two differentiation terms, 3 and 5 days (3 d and 5 d MΦ). Adiponectin (10 mkg/mL) stimulated the expression of apoA-1 gene at the mRNA level in 5 d MΦ, but not in 3 d MΦ. The level of apoE mRNA in MΦ under the action of adiponectin was not affected. Adiponectin suppressed macrophage TNF gene expression, while it induced the expression of IL-10 gene in 5d MΦ. The secreted levels of apo A-1 and E proteins under the action of adiponectin in macrophages of both periods of differentiation remained unchanged, while the level of the surface apo A-1 protein in 5 d MΦ was decreasing. Incubation of 5 d MΦ with the antagonist of the PPARα nuclear receptor, MK-886, or with the nuclear receptor LXR agonist, TO-901317, resulted in the cancellation of the stimulating effect of adiponectin on apoA-1 gene expression. These data indicate that adiponectin, in addition to its anti-inflammatory action, has a modulating effect on production of apo A-1 by macrophages. The latter is probably one of the mechanisms of the influence of this adipokine on atherogenesis.