MiR-127-3p impairs cellular functions associated with vascular remodeling, but does not induce a senescent phenotype in VSMCs

Phenotypically changed and senescent vascular smooth muscle cells (VSMC) contribute to the progression of vascular diseases such as atherosclerosis. Micro RNAs (miRs) are promising therapeutic targets due to their cell-specific functions. Targeting miR-127-3p emerges as an attractive approach to counteract vascular remodeling.
This study focuses on elucidating the role of miR-127-3p in VSMC focusing on cellular functions to reveal insights into plaque progression.

Utilizing reverse transcription and qRT-PCR we checked expression levels of miR-127-3p in human and murine VSMCs. Through pre-miR transfection followed by qRT-PCR, different functional assays, and fluorescence microscopy, we examined the impact of miR-127-3p overexpression on cellular senescence and cellular functions. Potential targets were selected via target prediction analysis and verified on mRNA and protein levels.

MiR-127-3p expression is downregulated in the aorta of ApoE-/- mice (**** p<0.0001). However, it is highly upregulated in aged C57BL/6J mice (3 months vs. 22 months, p<0.0001). Upregulation of miR-127-3p expression was also observed in femoral artery tissue on day 10 after wire-induced injury in C57BL/6J mice, serving as a restenosis model (p<0.001). In vitro, replicative senescent VSMCs exhibit increased miR-127-3p expression (p<0.05). Expression of miR-127-3p was also increased after IFNƴ stimulation in non-senescent VSMCs (p<0.05).
MiR-127-3p overexpression reduces proliferation in replicative senescent (p<0.001) and non-senescent (p<0.01) VSMCs. It hinders migration in non-senescent VSMCs (p<0.0001) but has a reverse effect in replicative senescent VSMCs (p<0.01). Production of reactive oxygen species is increased in non-senescent VSMCs after overexpression of miR-127-3p (p<0.5), whereas there was no effect on replicative senescent VSMCs.
Senescence marker LaminB1 showed a decreased expression after overexpression of miR-127-3p on mRNA level (p<0.05) in non-senescent and replicative senescent VSMCs. In non-senescent cells IL-6 (p<0.05) and IL-1ß (p<0.05) showed an increased expression, other cytokines showed a similar tendency. However, SMTN (p<0.05) expression was also increased after miR-127-3p overexpression.
Pre-miR transfection did not lead to significant differences in size of cell nuclei, ß-Galactosidase activity, and telomere length neither in non-senescent nor in replicative senescent VSMCs.
Targets of miR-127-3p, including mTor, were identified on mRNA and protein level. On mRNA level mTor was downregulated in non-senescent and replicative senescent VSMCs (p<0.05). In non-senescent VSMCs expression of Phospho-mTor (p<0.05) was upregulated on protein level after pre-miR transfection.

The study provides compelling evidence that miR-127-3p plays a role in the phenotypical switch of VSMCs and significantly influences cellular functions such as proliferation, migration, and the production of reactive oxygen species. The results indicate that miR-127-3p is a key contributor to the progression of vascular diseases and suggest that targeting miR-127-3p could be an effective approach for counteracting vascular remodeling. However, the study also emphasizes the need for further research to validate miR-127-3p as a potential therapeutic target for vascular remodeling in both in vitro and in vivo settings.