Abstract 15893: The MiR-30 Family is Regulated by Shear Stress and Affects the Expression of Inflammatory Cell-Cell Adhesion Molecules
Laminar blood flow exerting high shear stress on the endothelium is known to prevent local atherosclerosis formation and reduces apoptosis and inflammatory pathways in endothelial cells (ECs). MicroRNAs (miRs) are endogenously expressed small noncoding RNA molecules that regulate gene expression at the posttranscriptional level by binding to the mRNAs of their target genes, thereby inducing mRNA degradation or inhibition of translation. In a miR microarray analysis, we showed that exposure of human umbilical vein ECs (HUVECs) to laminar shear stress in a cone-and-plate apparatus for 36 hours up-regulates members of the miR-30 family, which consists of miR-30a, -30b, -30c, -30d and -30e. qPCR analysis confirmed a significant rise of miR-30b (1.7-fold) and miR-30c (1.6-fold vs. static control). Likewise, the expression of all miR-30 family members was increased by 1.2- to 1.5-fold when using a pump-driven laminar flow chamber system (IBIDI). To determine the regulation of the miR-30 cluster, we overexpressed the shear-induced transcription factor Kruppel-like factor 2 (KLF2). KLF2 overexpression induced a 1.7- to 2-fold upregulation of the miR-30 family members (p<0.05 vs. control). Since miR-30 family members are predicted to affect apoptosis and inflammation associated genes, we further characterized the function of miR-30 family members. Overexpression of miR-30a and -30b in HUVECs by transfection of commercially available precursor molecules (Pre-miR) decreased the pro-apoptotic proteins BIM (Pre-30a: 46±6%, Pre-30b: 48±13% of control) and Caspase-3 (Pre-30a: 63±8%, Pre-30b: 58±8% of control). Moreover, miR-30a and miR-30b significantly reduced the TNF-α-induced expression of the cell-cell adhesion molecule E-selectin (Pre-30a: 53±8%, Pre-30b: 33±7% of control) and showed a trend towards a decrease of the TNF-α-induced expression of vascular cell adhesion molecule 1 (VCAM-1). In summary, the miR-30 family may act in an anti-apoptotic and anti-inflammatory manner in ECs by regulating the expression of the apoptosis regulators BIM and Caspase-3 as well as the cell-cell adhesion molecules E-selectin and VCAM-1. The up-regulation of the miR-30 family members may contribute to the well-known atheroprotective effects of shear stress.
- © 2011 by American Heart Association, Inc.