MiR-92b-3p influences apoptosis in vascular smooth muscle cells by targeting BCL2L11, offering potential new therapeutic strategies for vascular remodeling

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. Here, we propose that BCL2L11 is targeted by miR-92b-3p, prompting an investigation into its role in regulating apoptosis in SMCs to employ miRNA-based targeted interventions to discover a novel therapeutic axis in vascular remodeling.
miR-92b-3p expression was studied in murine tissue and human vascular SMC and endothelial cells (EC) by qRT-PCR. Lipotransfection was used to modulate miR-92b-3p or BCL2L11 expression in human vascular cells with a high transfection efficiency. Methods to study the effect of miR92b-3p regulation on the cells included functional assays such as proliferation, migration, and cell death. Further target regulation was assessed by qRT-PCR, and Western Blot. Immunofluorescence microscopy was performed to determine cell morphology.
MiR-92b-3p is strongly regulated over time in vivo in ApoE-knockout mice (p<0.001) and in a model of wire-induced vascular injury (p<0.01). Further, it demonstrates heightened levels in SMCs compared to ECs in vitro and in vivo (p<0.01). 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). In contrast, the 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). Live-cell imaging demonstrates a decrease in SMC count post-anti-miR-92b-3p treatment (p<0.01), accompanied by cell shrinkage 72 hours after treatment (p<0.05). Further, apoptosis is increased in SMCs cultured in growth medium after lowering miR-92b-3p (p<0.05), but this effect is not observed in ECs, or SMCs treated with basal medium. BCL2L11 as a direct target shows increased expression after suppressing miR-92b-3p and decreased expression following the introduction of pre-miR-92b-3p in SMCs, at both the mRNA and protein levels (p<0.01). Stimulation by growth factors leads to an increase in miR-92b-3p levels (p>0.05) and a decrease in BCL2L11 expression in SMCs. Silencing BCL2L11 in SMCs eliminates apoptosis caused by lowering miR-92b-3p (p<0.05). Conversely, in apoptotic SMCs, increased miR-92b-3p shields cells from apoptosis (p<0.05).
This study underscores the critical role of miR 92b-3p as a central regulator of functional alterations in vascular SMC, which are pivotal in shaping and exacerbating vascular pathological conditions. In summary, we could show that miR-92b-3p efficiently controls apoptosis in SMCs by specifically targeting BCL2L11. This regulatory effect is limited to proliferating SMCs. Therapeutic regulation might present a promising strategy for stabilizing critical plaques, restoring the function of vascular cells, and thereby preventing vascular remodeling.