Insulin promotes vascular smooth muscle cell proliferation... : Journal of Hypertension (original) (raw)

Original papers: Blood vessels

Insulin promotes vascular smooth muscle cell proliferation via microRNA-208-mediated downregulation of p21

Zhang, Yea,b; Wang, Yanc; Wang, Xukaia,b; Zhang, Yid; Eisner, Gilbert M.e; Asico, Laureano D.f; Jose, Pedro A.f; Zeng, Chunyua,b

aDepartment of Cardiology, Daping Hospital, The Third Military Medical University

bChongqing Institute of Cardiology

cDepartment of Medical Genetics

dDepartment of Cell Biology, The Third Military Medical University, Chongqing, P.R. China

eDepartment of Medicine, Georgetown University Medical Center

fCenter for Molecular Physiology Research, Children′s National Medical Center and Department of Pediatrics, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA

Correspondence to Dr Chunyu Zeng, Department of Cardiology, Daping Hospital, The Third Military Medical University, Yuzhong Qu, Daping Changjiang Zhilu Rd, #10, Chongqing 400042, P.R. China Tel: +86 23 68757808; fax: +86 23 68757808; e-mail: [email protected]

Abbreviations: 30UTR, 30 untranslated region; CDK, cyclin-dependent kinase; FACS, fluorescence-activated cell sorting; miRNAs, MicroRNAs; PBS, phosphate-buffered saline; Pol II, polymerase II; TBST, Tris-buffered saline/Tween buffer; VSMC, vascular smooth muscle cell

Received 28 December, 2010

Revised 12 April, 2011

Accepted 18 May, 2011

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Erratum

Abstract

Objective

Abnormal vascular smooth muscle cell (VSMC) proliferation is involved in the development of vascular diseases. However, the mechanisms by which insulin exerts this effect are not completely known. We hypothesize that microRNAs might be involved in insulin-induced VSMC proliferation.

Methods

VSMC proliferation was determined by [3H]-thymidine incorporation; microRNAs were determined by microRNA chips and real-time PCR; and p21expression was determined by immunoblotting.

Results

In this study, we found that insulin increased VSMC proliferation and miR-208 expression. Overexpression of miR-208 increased basal and insulin-mediated VSMC proliferation. Although a miR-208 inhibitor, by itself, had no effect on VSMC proliferation, it reduced the insulin-mediated cell proliferation. Moreover, miR-208 increased the transformation of cell cycle from G0/G1 phase to the S phase. Bioinformatics analysis found that p21, a member of the cyclin-dependent kinase (CDK)-inhibitory protein family, may be the target of miR-208. Insulin decreased p21 expression in VSMCs; transfection of miR-208 also decreased p21 protein expression. In the presence of miR-208 inhibitor, the inhibitory effect of insulin on p21 expression in VSMCs was partially blocked. The interaction between miR-208 and p21 was direct. Using a luciferase reporter with entire wild-type p21 3′UTR or a mutant p21 3′UTR in HEK293 cells, we found that miR-208 decreased but neither miR-208 mimic nor the mutant p21 3′UTR had any significant effect on the luciferase activity.

Conclusion

This study indicates that miRNAs, miR-208, in particular, are involved in the insulin-induced VSMC proliferation via downregulation of its potential target, p21, a key member of CDK-inhibitory protein family.

Erratum

In addition to Dr Chunyu Zeng, Dr Xukai Wang is also a corresponding author . Thus, the corresponding author section should read:

Correspondence to Dr Xukai Wang and Dr Chunyu Zeng, Department of Cardiology, Daping Hospital, The Third Military Medical University, Yuzhong Qu, Daping Changjiang Zhilu Rd, #10, Chongqing 400042, P.R. China

Tel: +86 23 68757808; fax: +86 23 68757808;

e-mail: [email protected]; [email protected]

Journal of Hypertension. 29(10):2046, October 2011.