Abstract 14742: MicroRNA-30 Mediates Shear Stress-Induced Anti-Inflammatory Properties of Endothelial Cells via Angiopoietin-2
Laminar blood flow exerts high shear stress on the endothelium, which is known to prevent local atherosclerosis formation and inhibits 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.
Using gene set enrichment analysis of microarray expression profiling of shear stress exposed HUVECs, we found that the sequence complementary to the miR-30 seed is enriched in genes that are downregulated by shear stress. Consistently, miR microarray analysis showed that exposure of human umbilical vein ECs (HUVECs) to prolonged laminar shear stress up-regulates all members of the miR-30 family, which consists of miR-30a, -30b, -30c, -30d and -30e (1.6- to 2.0-fold, p<0.05). To determine the regulation of miR-30, we overexpressed the shear-induced transcription factor Krüppel-like factor 2 (KLF2). KLF2 overexpression induced a 1.7- to 2.1-fold upregulation of the miR-30 family members (p<0.05). Since miR-30 family members are predicted to affect inflammation associated genes, we further characterized the function of miR-30 family members. Overexpression of miR-30a and -30b in HUVECs by transfection of precursor miRs (Pre-miR) reduced the TNF-α-induced expression of the cell-cell adhesion molecules E-selectin, VCAM1 and ICAM1 (by 30±14% to 53±15% of control, p<0.05). Furthermore, miR-30 is predicted to target the 3’UTR of Angiopoietin-2 (Ang2) and overexpression of miR-30 inhibits the expression of Ang2, while miR-30 inhibition using LNA-modified antisense oligonucleotides induces Ang2 expression. KLF2 overexpression also reduces Ang2 levels. Stimulation with recombinant Ang2 alleviates the anti-inflammatory properties of miR-30 overexpression, indicating a causal role of Ang2 for the effects of miR-30.
In summary, the miR-30 family acts in an anti-inflammatory manner in ECs by regulating the expression of the cell-cell adhesion molecules E-selectin, VCAM1 and ICAM1 in an Ang2-dependent manner. The up-regulation of the miR-30 family members may contribute to the atheroprotective effects of shear stress.
- © 2013 by American Heart Association, Inc.