In vascular disease, cells undergo important alterations in cellular function, influencing vascular homeostasis. Apoptosis is one of these functions, affecting vascular tone and plaque stability. Influencing this process for example, by targeting microRNAs is key for therapeutic strategies tackling vascular diseases in a cell-specific manner. We identified the critical role of miR92b-3p on the functional properties of vascular cells. Studying human primary coronary artery smooth muscle cells (SMCs) and human umbilical vein endothelial cells (ECs), methods included expression analysis in mice tissue after restenosis by wire-induced injury and in atherosclerosis. The role of miR-92b on cellular function and target regulation was determined by pre- and antagomir transfection. Initial analysis in vivo showed miR92b-3p to be significantly upregulated in atherosclerosis (p<0,01) and regulated in restenosis (p<0,05). Under growth conditions in both ECs and SMCs, miR-92b-3p was significantly higher expressed (p<0,05). In SMCs, upregulation of miR92b-3p resulted in increased proliferation (p<0,01) and significantly enhanced cell migration in SMCs (p<0,001) but hampered migration in ECs (p<0,01). Downregulation of miR-92b-3p in SMC resulted in decreased migrational (p<0.001) and proliferative capacity (p<0.001), accompanied by a reduction in metabolic activity (p<0.05) and, exclusively in SMCs, increased apoptosis (p<0.05). In ECs, proliferation was enhanced following downregulation (p<0,01). Multiple targets were identified, using Western blot and qPCR including KLF4 (p<0,01), DKK3 (p<0,05), Notch1 (p<0,01), PTEN (p<0,05), and especially in SMC, Bim (p<0,001). Regulation of Bim by miR92b-3p and subsequent apoptosis was then evaluated by siRNA-knockdown experiments, confirming their strong interaction. We further verified the crucial role of miR-92b-3p by reversing cell death in apoptotic SMCs through miR-92b-3p overexpression experiments (p<0.05). This study reports miR 92b-3p to be a crucial regulator of vascular function. Therapeutic regulation might present a promising strategy for stabilizing critical plaques, restoring the function of vascular cells, and thereby preventing vascular remodeling.
Read full abstract