Transcriptional changes upon overexpression of seven candidate miRNAs in human saphenous vein endothelial cells. [HSVEC]

Proliferation of vascular smooth muscle cells (vSMCs) following injury is a crucial factor contributing to pathological vascular remodelling. MicroRNAs (miRNAs) are powerful gene regulators and attractive therapeutics agents. Here, we aim to systemically identify and characterise miRNAs with therapeutic potential in targeting aberrant vSMC proliferation. We performed a high-throughput in vitro screen using a library of 2042 human miRNA-mimics for their impact on VSMC proliferation and identified seven novel antiproliferative miRNAs i.e miR-1827, miR-4774-3p, miR-5681b, miR-449b-5p, miR-491-3p, miR-323a-3p, and miR-892b.Overexpression of these 7 miRNAs affects proliferation of vSMCs from different vascular beds. Focusing on vein graft failure, a condition in which miRNA based therapeutics can be applied to the graft ex-vivo, we showed that these miRNAs reduced human saphenous vein SMC (HSVSMC) proliferation without inducing apoptosis or senescence, and five of them also significantly decreased migration.In contrast to HSVSMC, miRNA overexpression on saphenous vein endothelial cells (ECs) led to no or lower decrease of proliferation for the seven miRNAs. We performed RNA-seq on HSVEC overexpressing the seven miRNAs and showed a limited response of ECs to the miRNA overexpression. Overall design: After inducing quiescence by culturing the cells in 0.2% FBS for 12h, human saphenous vein endothelial cells were transfected with miRNA mimics of the 7 miRNA candidates for six hours (miR-1827, miR-4774-3p, miR-5681b, miR-449b-5p, miR-491-3p, miR-323a-3p, and miR-892b or mimic Control) then cultured in 10% FBS for 48h to promote a proliferative phenotype. Three biological replicates were performed with each replicate corresponding to cells derived from different patients. RNA sequencing was performed on HSVSMCs treated with each mimic miRNA, a control mimic or untransfected cells.