Elsevier

Atherosclerosis

Volume 243, Issue 2, December 2015, Pages 477-485
Atherosclerosis

Alpha1beta1 and integrin-linked kinase interact and modulate angiotensin II effects in vascular smooth muscle cells

https://doi.org/10.1016/j.atherosclerosis.2015.09.026Get rights and content
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Highlights

  • Alpha1beta1 integrin modulates Ang II-induced VSMC migration and proliferation.

  • Ang II effects on VSMC rely on a sequential NOX1–NOX2 activation.

  • Activation of alfa1beta1 integrin signaling modulates Ang II-induced NOX2 activation.

  • NOX1 activation triggers alpha1beta1 integrin/ILK/AKT/NOX2 pathway in VSMC.

  • Crosstalk between NOX and alfa1beta1 integrin modulates Ang II effects on VSMC.

Abstract

The effects of angiotensin II (Ang II) on vascular smooth muscle cells (VSMC) are modulated by reactive oxygen species (ROS) and also involve integrin engagement. However, the potential link between alpha1beta1 integrin signaling with NOX system and their combined contribution to Ang II effects on VSMC have not been investigated. We aimed to elucidate the moslecular mechanisms underlying the activation of these two pathways in Ang II effects on VSMC.

Ang II-induced VSMC migration (2-fold increase) and proliferation (2.5-fold increase) is modulated by alpha1beta1 integrin, being inhibited by obtustatin, a specific alpha1beta1 integrin blocker. Ang II also stimulates ROS production in VSMC (140%) that is NOX1 dependent, being completely inhibited in NOX1 silenced cells. The ROS production develops in two peaks, and the second peak is maintained by NOX2 activation. Apocynin and obtustatin inhibit the NOX2-associated second peak, but not the first peak of ROS production, which is related to NOX1 activation. Corroborating the involvement of alpha1beta1 integrin, the pretreatment of VSMC with obtustatin impaired Ang II-induced FAK phosphorylation, AKT activation, p21 degradation and the increase of ILK expression. Silencing of ILK blocked cell migration, AKT phosphorylation and the second peak of ROS, but partially inhibits (70%) VSMC proliferation induced by Ang II.

The data demonstrate a novel role for NOX2 in Ang II effects on VSMC, and suggest alpha1beta1 integrin and ILK as target molecules to the development of more effective therapeutic interventions in cardiovascular diseases.

Keywords

Vascular smooth muscle cell
Angiotensin II
NOX
Alpha1beta1 integrin
ILK
Obtustatin

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