MicroRNA-regulated pathways of flow-stimulated angiogenesis and vascular remodeling in vivo

Abstract

Background: Vascular shear stress promotes endothelial cell sprouting in vitro. The impact of hemodynamic forces on microRNA (miRNA) and gene expression within growing vascular networks in vivo, however, remain poorly investi‑ gated. Arteriovenous (AV) shunts are an established model for induction of neoangiogenesis in vivo and can serve as a tool for analysis of hemodynamic efects on miRNA and gene expression profles over time. Methods: AV shunts were microsurgically created in rats and explanted on postoperative days 5, 10 and 15. Neoan‑ giogenesis was confrmed by histologic analysis and micro-computed tomography. MiRNA and gene expression pro‑ fles were determined in tissue specimens from AV shunts by microarray analysis and quantitative real-time polymer‑ ase chain reaction and compared with sham-operated veins by bioinformatics analysis. Changes in protein expression within AV shunt endothelial cells were determined by immunohistochemistry. Results: Samples from AV shunts exhibited a strong overexpression of proangiogenic cytokines, oxygenationassociated genes (HIF1A, HMOX1), and angiopoetic growth factors. Signifcant inverse correlations of the expressions of miR-223-3p, miR-130b-3p, miR-19b-3p, miR-449a-5p, and miR-511-3p which were up-regulated in AV shunts, and miR-27b-3p, miR-10b-5p, let-7b-5p, and let-7c-5p, which were down-regulated in AV shunts, with their predicted interacting targets C–X–C chemokine receptor 2 (CXCR2), interleukin-1 alpha (IL1A), ephrin receptor kinase 2 (EPHA2), synaptojanin-2 binding protein (SYNJ2BP), forkhead box C1 (FOXC1) were present. CXCL2 and IL1A overexpression in AV shunt endothelium was confrmed at the protein level by immunohistochemistry. Conclusions: Our data indicate that fow-stimulated angiogenesis is determined by an upregulation of cytokines, oxygenation associated genes and miRNA-dependent regulation of FOXC1, EPHA2 and SYNJ2BP.