miRNA-34a reduces neointima formation through inhibiting smooth muscle cell proliferation and migration.
OBJECTIVE
We have recently reported that microRNA-34a (miR-34a) regulates vascular smooth muscle cell (VSMC) differentiation from stem cells in vitro and in vivo. However, little is known about the functional involvements of miR-34a in VSMC functions and vessel injury-induced neointima formation. In the current study, we aimed to establish the causal role of miR-34a and its target genes in VSMC proliferation, migration and neointima lesion formation.


RESULTS
Various pathological stimuli regulate miR-34a expression in VSMCs through a transcriptional mechanism, and the P53 binding site is required for miR-34a gene regulation by these stimuli. miR-34a over-expression in serum-starved VSMCs significantly inhibited VSMC proliferation and migration, while knockdown of miR-34a dramatically promoted VSMC proliferation and migration, respectively. Notch homolog 1 (Notch1), a well-reported regulator in VSMC functions and arterial remodeling, was predicted as one of the top targets of miR-34a by using several computational miRNA target prediction tools, and was negatively regulated by miR-34a in VSMCs. Luciferase assay showed miR-34a substantially repressed wild type Notch1-3'-UTR-luciferase activity in VSMCs, but not mutant Notch1-3'-UTR-luciferease reporter, confirming the Notch1 is the functional target of miR-34a in VSMCs. Data from co-transfection experiments also revealed that miR-34a inhibited VSMC proliferation and migration through modulating Notch gene expression levels. Importantly, the expression level of miR-34a was significantly down-regulated in injured arteries, and miR-34a perivascular over-expression significantly reduced Notch1 expression levels, decreased VSMC proliferation, and inhibited neointima formation in wire-injured femoral arteries.


CONCLUSIONS
Our data have demonstrated that miR-34a is an important regulator in VSMC functions and neointima hyperplasia, suggesting its potential therapeutic application for vascular diseases.
Department of Cardiology, The First Affiliated Hospital, School of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou 310003, Zhejiang, China.
Qishan
Q
Chen
Department of Cardiology, The First Affiliated Hospital, School of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou 310003, Zhejiang, China.
Feng
F
Yang
Department of Cardiology, The First Affiliated Hospital, School of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou 310003, Zhejiang, China.
Meiqun
M
Guo
Centre for Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK.
Guanmei
G
Wen
Centre for Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK.
Cheng
C
Zhang
Centre for Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK.
Le Anh
le A
Luong
Department of Cardiology, The First Affiliated Hospital, School of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou 310003, Zhejiang, China. Electronic address: zjh_john@medmail.com.cn.
Jianhua
J
Zhu
Centre for Clinical Pharmacology, William Harvey Research Institute, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London EC1M 6BQ, UK.
Qingzhong
Q
Xiao
Department of Cardiology, The First Affiliated Hospital, School of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou 310003, Zhejiang, China. Electronic address: li_zhang@zju.edu.cn.
Li
L
Zhang
D000818:Animals; D017209:Apoptosis; D001483:Base Sequence; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation; D005263:Femoral Artery / Q000293:injuries / Q000473:pathology; D005786:Gene Expression Regulation; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000473:pathology*; D058426:Neointima / Q000235:genetics* / Q000473:pathology*; D010641:Phenotype; D051880:Receptors, Notch / Q000378:metabolism; D014158:Transcription, Genetic; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
C551848:MIRN34a microRNA, mouse; D035683:MicroRNAs; D051880:Receptors, Notch; D016159:Tumor Suppressor Protein p53
Cell migration; Cell proliferation; MiRNA-34a; MicroRNAs; Neointima; Notch1; Post-angioplasty restenosis; Vascular smooth muscle cells