Effect of the insulin on the apolipoprotein a-i gene expression in human macrophages

The aim of the article — to study the effect of insulin on apolipoprotein A-I gene expression level in human macrophages and to reveal the main signal cascades which take part in the insulin-mediated regulation of apolipoprotein A-I gene. Materials and methods. The experiments were carried out on the macrophages differentiated from acute monocytic leukemia cell line THP-1 and on the macrophages differentiated from the monocytes isolated from peripheral human blood. The analysis of apoA-I gene expression was performed by RealTime RT-PCR (on the mRNA level) and by flow cytofluorometry. To study the signalling cascades which take part in the insulin-mediated regulation of apoA-I gene the inhibitory analysis was used. Results. Insulin induces the human apoA-I gene transcription in macrophages, but decreases the level of the ApoA-I protein which binds to outer cytoplasmic membrane of macrophages. The insulin-mediated transcription of apoA-I gene depends on PI3K-AKT signal cascade and transcription factors NF-κB and LXRs. Conclusions. Taking into account our previous data it is plausible to conclude that the elevation of ApoA-I mRNA in human macrophages after insulin treatment leads to an increase of the amplitude of macrophages anti-inflammatory response, which consists in a sharp rise in the level of surface ApoA-I in macrophages under the some proinflammatory stimuli (TNFα, LPS).