Abstract
OBJECTIVES:Vascular injury is an early manifestation and a cause of end-organ damage in hypertension. We profiled vascular injury-associated microRNAs (miRs) to identify key miR regulators of gene expression that could be used as novel therapeutic targets.
METHODS:Ten week-old male C57BL/6 mice were infused SC or not with angiotensin (Ang) II for 14 days. Blood pressure (BP) was measured by telemetry. RNA was extracted from mesenteric arteries (MA) and used for small RNA and total RNA sequencing using Illumina HiSeq-2500. A candidate gene approach was used to identify potential key miR regulators involved in Ang II-induced vascular injury. Their regulatory mechanism was validated using human vascular smooth cells (VSMCs). We then tested whether intravenous injection of miR inhibitors protects against Ang II-induced BP elevation, MA injury by pressurized myography, and oxidative stress by dihydroethidium staining.
RESULTS:Ang II infusion caused MA differential expression of 35 miRs that are part of an important miR-transcription factor (TF) co-regulatory network modulating genes involved in extracellular matrix and developmental processes. The up-regulated miR-431-5p was identified as a potential key regulator. Gain- and loss-of-function in VSMCs demonstrated that miR-431-5p directly targets the TF Ets homologous factor (EHF), leading to up-regulation of collagen type I alpha 1 chain, miR-431-5p and miR-382-5p through EHF down-regulation. IV injections of miR-431-5p inhibitors delayed Ang II-induced BP elevation, and reduced MA dysfunction, stiffening and oxidative stress in mice.
CONCLUSION:This study identified miR-431-5p as a key regulator in Ang II-induced vascular injury. miR-431-5p knockdown possesses potential value for the treatment of hypertension and vascular damage.