Abstract 16334: Inhibition of 14q32 MicroRNAs Drastically Improves Blood Flow Recovery After Ischemia
Arteriogenesis is a multifactorial process in which pre-existing arterioles remodel into mature collateral arteries, restoring blood flow after ischemia. Clinical trials designed to stimulate arteriogenesis have been unsuccessful, mainly because only single pathways involved in arteriogenesis were targeted. As microRNAs (miRs) regulate expression of several hundred target genes, we set out to identify miRs that target genes in all pathways of arteriogenesis. Using www.targetscan.org, we performed a reverse target prediction on a first set of 127 genes involved in arteriogenesis and on a second set of 90 additional genes that we found upregulated in adductor muscles of C57Bl/6 mice subjected to hind limb ischemia (HLI) via single femoral artery ligation, a model for effective arteriogenesis. In both analyses we found enrichment of binding sites for miRs in a 14q32 miR gene cluster. MicroArray analyses showed that 14q32 miRs were down-regulated drastically in adductor muscles of C57Bl/6 mice after HLI. Novel miR inhibitors, Gene Silencing Oligonucleotides (GSOs), were used to inhibit four 14q32 miRs, miR-487b, miR-494, miR-329 and miR-495 in vivo (1mg/mouse), 1 day prior to induction of HLI via double ligation of the left femoral artery. Blood flow recovery was followed by Laser Doppler Perfusion Imaging. All 4 GSOs clearly improved blood flow recovery after HLI. GSOs targeting miR-495 and miR-329 showed robust effects. Mice treated with GSO-495 or GSO-329 showed increased perfusion already after 3 days (30% perfusion vs. 15% in control) and those treated with GSO-329 showed a remarkable full recovery of perfusion after 7 days (vs. 60% in control). Targets of miR-329 include a confirmed site in the VEGFA gene. GSOs gave stable knockdown of their target miRs in the target tissue up to 17 days, and gave a more specific knockdown than classic antagomiRs in primary human arterial cells. Inhibition of 14q32 miRs with GSOs provides a powerful therapeutic tool in arteriogenesis.
- © 2012 by American Heart Association, Inc.