Targeted inhibitory effect of Lenti-SM22alpha-p27-EGFP recombinant lentiviral vectors on proliferation of vascular smooth muscle cells without compromising re-endothelialization in a rat carotid artery balloon injury model.

Liang Jing,Xiang Luo,Jiagao Lü,Wenlong Wang,Shuangshuang Zhang,Minjie Xie,Daishi Tian,Qin Ning,Daowen Wang,Wei Wang,Xiao Xiao

doi:10.1371/journal.pone.0118826

Abstract

AimsIn-stent restenosis remains a serious problem after the implantation of drug-eluting stents, which is attributable to neointima formation and re-endothelialization. Here, we tried to find a new method which aims at selectively inhibiting proliferation of vascular smooth muscle cells (VSMC) proliferation without inhibition of re-endothelialization.Methods and ResultsWe used the smooth muscle-specific SM22alpha promoter in a recombinant lentiviral vector to drive overexpression of cell-cycle inhibitor, p27, in VSMCs. p27 effectively inhibited VSMC proliferation mediated by cell cycle arrest at the G0/G1 checkpoint. The SM22alpha-p27 lentiviral vector inhibited VSMC proliferation more effectively than paclitaxel. Rats infected with Lenti-SM22alpha-p27 had a significantly lower intima/media (I/M) ratio and also showed inhibition of restenosis on day 28 after balloon injury. Moreover, the repair of injured endothelium, and re-endothelialization of the carotid artery wall, was not affected by the smooth muscle cell-specific expression of p27.ConclusionA recombinant lentiviral vector carrying the SM22alpha promoter was used to effectively infect and selectively overexpress p27 protein in VSMCs, leading to inhibition of intimal hyperplasia without compromising endothelial repair.

Highlights

Percutaneous transluminal coronary angioplasty has been reported to result in a restenosis rate of about 40% to 50% [1, 2]
We used the smooth muscle-specific SM22alpha promoter in a recombinant lentiviral vector to drive overexpression of cell-cycle inhibitor, p27, in vascular smooth muscle cells (VSMC). p27 effectively inhibited VSMC proliferation mediated by cell cycle arrest at the G0/G1 checkpoint
P27 was overexpressed in the nucleus in the Lenti-SM22alpha-p27 group (Fig. 1 a3), whereas p27 in the Lenti-SM22alpha-null group was distributed in the nucleus along with a certain amount of cytoplasmic expression (Fig. 1 a2)

Summary

Introduction

Percutaneous transluminal coronary angioplasty has been reported to result in a restenosis rate of about 40% to 50% [1, 2]. The challenges with using DES include: 1) non-selective drug intervention which effectively inhibits the proliferation of VSMCs (vascular smooth muscle cells), and inhibits endothelial proliferation, and the progression of re-endothelialization which can result in a loss of contact inhibition in VSMCs [5]. Anticancer drugs have been shown to effectively inhibit VSMC proliferation, this is accompanied by a restenosis rate of 5% -10%, and anticancer drugs such as paclitaxel cause hyperlipidemia with bone marrow suppression and side effects [6, 7]. An ideal coating drug should selectively inhibit the proliferation of VSMCs while maintaining the functional integrity of VECs (vascular endothelial cells). The SM22 5’-flanking sequence was shown to be necessary and sufficient to efficiently drive the transcription of a luciferase reporter gene in both primary rat aortic VSMCs and A7r5 cells in vitro [12]

Methods

Results

Conclusion