OS073. Over-expression of MIRNA-203 results in increased inflammatory response in endothelial cells: a mechanism of increased endothelial inflammatory response in preeclampsia

Abstract

MicroRNAs are small, non-coding RNAs that post-transcriptionally regulate gene expression and play important roles in various biological and pathological processes. Several miRNAs have been found to regulate endothelial cell (EC) function. Studies have shown that miR-203 plays an important role in the inflammatory response. The present study was designed to specifically investigate miR-203 in the regulation of endothelial inflammatory responses and to determine if over-expression of miR-203 expression could lead to increased inflammatory response that is associated with endothelial activation/dysfunction in preeclampsia (PE). Total RNA was isolated from ECs from 8 normal and 11 PE pregnancies. miR-203 expression was determined by real-time PCR. Relative miR-203 expression was calculated by comparative CT with formula 2(-ΔΔCt). To determine if increased miR-203 expression is associated with increased EC inflammatory response, ECs were transfected with pre-miR-203. Successful transfection of pre-miR-203 in ECs was confirmed by RT-PCR and U6 expression. EC production of ICAM, IL-6, and IL-8 were measured by ELISA. EC mRNA expressions for ICAM, IL-6, and IL-8 were determined by RT-PCR. miR-203 induced increased inflammatory response was also determined by leukocyte-endothelial adhesion assay. Leukocyte myeloperoxidase (MPO) activity was measured as an indicator of leukocyte adhesion. (1) miR-203 expression was significantly increased in ECs from PE compared to normal pregnant controls (p<0.05) and the increased miR-203 expression was associated with increased ICAM expression in PE-ECs; (2) ICAM, IL-6, and IL-8 production and expression were significantly increased in ECs transfected with pre-miR-203, p<0.01; (3) MPO activity was significantly increased in ECs transfected with miR-203 compared to the controls, p<0.05. miR-203 expression is increased in PE-ECs. Over-expression of miR-203 in ECs results in: (1) increased endothelial adhesion molecule ICAM production and expression; (2) increased inflammatory cytokine IL-6 and IL-8 productions and expressions; and (3) increased leukocyte and endothelial adhesion. Increased endothelial adhesion molecule expression and cytokine production are well-recognized endothelial inflammatory responses in PE. Therefore, our data provide strong evidence that increased miR-203 expression could be a molecular mechanism that leads to endothelial activation/dysfunction in PE.