Vascular smooth muscle cell proliferation is influenced by let-7d microRNA and its interaction with KRAS.
BACKGROUND
Several microRNAs (miRNAs) have been reported to regulate cardiovascular biological and pathological processes through inhibiting the translation of certain RNA transcripts. However, little is known about the association between miRNAs and vascular smooth muscle cell (VSMC) proliferation. The aim was to investigate the role of miRNAs in VSMC growth and the potential mechanism.


RESULTS
Primary VSMCs were isolated from the medial layer of the thoracic aorta obtained from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). miRNA microarrays were used to analyze the difference in miRNA expression between VSMCs of SHR and WKY rats and were validated using TaqMan real-time PCR. Of the potentially related genes under the influence of let-7d identified through literature search, KRAS was verified by western blot and functionally analyzed using miRNA mimics transfection and analysis of transfectants by cell enumeration was made using CCK-8 and flow cytometric analysis of cell cycle progression. let-7d-transfected VSMCs from SHR, WKY and human coronary arteries expressed significantly lower amounts of KRAS protein, displayed reduced cell growth and led to a greater number of cells in the G1 phase than the G2/M phases of the cell cycle.


CONCLUSIONS
let-7d was significantly downregulated in VSMCs as an important regulator of cell proliferation. RAS might be involved in the proliferation regulation by let-7d.
Department of Cardiology, Changhai Hospital, The Second Military Medical University, Shanghai, China.
Man-Li
ML
Yu
Jia-Feng
JF
Wang
Guo-Kun
GK
Wang
Xiao-Hua
XH
You
Xian-Xian
XX
Zhao
Qing
Q
Jing
Yong-Wen
YW
Qin
D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D005260:Female; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D023421:Models, Animal; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000378:metabolism*; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012844:Sincalide / Q000235:genetics / Q000378:metabolism; D014162:Transfection
C528430:Kras protein, rat; C548145:MIRNLET7 microRNA, rat; D035683:MicroRNAs; D016283:Proto-Oncogene Proteins p21(ras); D012844:Sincalide