Role of MEG3 in Cellular Physiology of Atherosclerosis.

Objective: To investigate the role of the lncRNA MEG3 (MEG3) in opposing the biochemical processes thought to be involved in the development of atherosclerosis (AS).

Methods: Thirty patients with AS and thirty healthy control subjects were enrolled in this study. The expression of MEG3, miR-200b-3p and ABCA1 was analyzed by RT-qPCR in the individuals and the macrophages-derived foam cells. Lipid accumulation was detected by oil red O staining. Cholesterol efflux was measured by ELISA assay in the foam cells. Expression of miR-200b-3p was identified by sequencing. Targeting relationships were determined by dual luciferase assay between MEG3 and miR-200b-3p, miR-200b-3p and ABCA1.

Results: In the patients with AS, MEG3 and ABCA1 expression were decreased and miR-200b-3p expression was upregulated. Foam cells transfected with an expression vector (pcDNA3.1) containing MEG3 (pcDNA3.1-MEG3) induced decrease of lipid accumulation and increase of cholesterol efflux compared to cells transfected with control plasmid alone. Foam cells transfected by pcDNA3.1-MEG3 also showed decreased miR-200b-3p and increased ABCA1 expression. Interestingly, co-expression of miR-200b-3p partially prevented these effects of MEG3 expression.

Conclusion: Expression of MEG3 is downregulated in the patients with AS and foam cells. Overexpressed MEG3 may act as an anti-atherosclerotic factor by reducing lipid accumulation and accelerating cholesterol efflux through the miR-200b-3p/ABCA1 axis.