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Updated: Jun 11, 2026

A Rat Carotid Artery Pressure-Controlled Segmental Balloon Injury with Periadventitial Therapeutic Application
Published on: July 9, 2020
Novel role of Egr-1 in nicotine-related neointimal formation
Roberto I Vazquez-Padron1, Dania Mateu, Luis Rodriguez-Menocal
1Department of Surgery and Vascular Biology Institute, University of Miami Miller School of Medicine, 1600 NW 10th Avenue, RMSB 7147A, Miami, FL 33136, USA.
Aims:
The aim of this study was to investigate the mechanisms by which nicotine increases vascular smooth muscle cell (VSMC) proliferation and post-injury neointimal formation.
Methods And Results:
Vascular injury was inflicted in the right iliac artery of nicotine-treated and control rats. Nicotine increased post-injury VSMC proliferation (Ki67(+) cells) and neointimal formation (neointima/media ratio, 0.42 ± 0.23 vs. 0.14 ± 0.07, P= 0.02). To determine the mechanisms by which nicotine exacerbates VSMC proliferation, cultured cells were exposed to nicotine, and signalling pathways leading to cell proliferation were studied. Nicotine activated extracellular signal-regulated kinase (ERK) 1/2 in a dose- and time-dependent manner. The blockade of this signalling axis abolished nicotine-mediated proliferation. Functional nicotinic acetylcholine receptors and Ca(2+) influx were necessary for ERK1/2 activation and nicotine-induced mitogenesis in VSMCs. Downstream to ERK1/2, nicotine induced the phosphorylation of Ets-like gene 1 in a timely co-ordinated manner with the up-regulation of the atherogenic transcription factor, early growth response 1 (Egr-1). The treatment of balloon-injured arteries with a lentivirus vector carrying a short hairpin RNA against Egr-1 abolished the deleterious effect of nicotine on vascular remodelling.
Conclusion:
Nicotine acts through its receptors in VSMC to activate the ERK-Egr-1 signaling cascade that induces cell proliferation and exacerbates post-injury neointimal development.
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