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Expression of insulin receptor (IR) A and B isoforms, IGF-IR, and IR/IGF-IR hybrid receptors in vascular smooth muscle cells and their role in cell migration in atherosclerosis

By N. Beneit, C. E. Fernández-García, J. L. Martín-Ventura, L. Perdomo, Ó. Escribano, J. B. Michel, G. García-Gómez, S. Fernández, S. Díaz-Castroverde, J. Egido, A. Gómez-Hernández and M. Benito

Abstract

International audienceAbstractBackgroundAbnormal proliferation and migration of vascular smooth muscle cells (VSMCs) is a major contributor to the development of atherosclerotic process. In a previous work, we demonstrated that the insulin receptor isoform A (IRA) and its association with the insulin-like growth factor-I receptor (IGF-IR) confer a proliferative advantage to VSMCs. However, the role of IR and IGF-IR in VSMC migration remains poorly understood.MethodsWound healing assays were performed in VSMCs bearing IR (IRLoxP+/+ VSMCs), or not (IR−/− VSMCs), expressing IRA (IRA VSMCs) or expressing IRB (IRB VSMCs). To study the role of IR isoforms and IGF-IR in experimental atherosclerosis, we used ApoE−/− mice at 8, 12, 18 and 24 weeks of age. Finally, we analyzed the mRNA expression of total IR, IRB isoform, IGF-IR and IGFs by qRT-PCR in the medial layer of human aortas.ResultsIGF-I strongly induced migration of the four cell lines through IGF-IR. In contrast, insulin and IGF-II only caused a significant increase of IRA VSMC migration which might be favored by the formation of IRA/IGF-IR receptors. Additionally, a specific IGF-IR inhibitor, picropodophyllin, completely abolished insulin- and IGF-II-induced migration in IRB, but not in IRA VSMCs. A significant increase of IRA and IGF-IR, and VSMC migration were observed in fibrous plaques from 24-week-old ApoE−/− mice. Finally, we observed a marked increase of IGF-IR, IGF-I and IGF-II in media from fatty streaks as compared with both healthy aortas and fibrolipidic lesions, favoring the ability of medial VSMCs to migrate into the intima.ConclusionsOur data suggest that overexpression of IGF-IR or IRA isoform, as homodimers or as part of IRA/IGF-IR hybrid receptors, confers a stronger migratory capability to VSMCs as might occur in early stages of atherosclerotic process

Topics: Insulin receptor, Migration, Vascular smooth muscle cells, Atherosclerosis, [ SDV ] Life Sciences [q-bio]
Publisher: BioMed Central
Year: 2016
DOI identifier: 10.1186/s12933-016-0477-3
OAI identifier: oai:HAL:inserm-01407063v1
Provided by: Hal-Diderot
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