Role of MT1-MMP in estrogen-mediated cellular processes of intimal hyperplasia.

Abstract

BACKGROUND:

Hormone replacement therapy increases intimal hyperplasia (IH) following vascular intervention. Matrix metalloproteinases (MMPs) play a role in IH development. We have shown estrogen up-regulates MT1-MMP expression, a transmembrane protein that activates MMP-2, and increases vascular smooth muscle cell (VSMC) collagen invasion via increased MMP-2 activity. Here we hypothesize inhibition of MT1-MMP will prevent hormonally-stimulated increased MMP-2 activation and the downstream cellular processes of IH pathogenesis.

METHODS:

VSMCs from a postmenopausal donor were transfected with MT1-MMP or negative control siRNAs, treated with estrogen (Est), analyzed by q-PCR, Western blot, zymography, migration, invasion, and proliferation assays.

RESULTS:

Est treatment of MT1-MMP silenced cells still resulted in increased MT1-MMP expression (C = 41% ± 4%; Est = 52% ± 2%; P < 0.05). Silencing of MT1-MMP decreased basal MMP-2 activity (nonsilenced = 100%; MT1-silenced = 87% ± 3%; P < 0.05) but had no effect on basal invasion or proliferation. Est treatment of MT1-MMP silenced cells still resulted in increased MMP-2 activity (C = 87% ± 3%; Est = 101% ± 4%; P < 0.05) and invasion (C = 89% ± 6%; Est = 109% ± 3%; P < 0.05) compared with MT1-MMP silenced control cells. However, silencing of MT1-MMP did inhibit Est- and serum-stimulated proliferation (C = 106% ± 18%; Est = 104% ± 16%; FBS = 121% ± 24%; P = NS).

CONCLUSION:

Silencing of MT1-MMP in aged VSMCs results in impaired but not complete inhibition of basal and Est-stimulated increases in MMP-2 activity. Other mechanisms appear to be playing a role in hormonally-regulated cellular processes of IH pathogenesis. Future studies will target other signaling cascades, with the goal of identifying mechanisms responsible for hormonally-modulated unbalanced MMPs. In vivo manipulation of the expression patterns of MT1-MMP will be examined for the prevention of IH in animal models of vascular disease.

• Authors: Deidra J H Mountain, Stacy S Kirkpatrick, Michael B Freeman, Scott L Stevens, Mitchell H Goldman, Oscar H Grandas
• Journal: The Journal of surgical research (J Surg Res) Vol. 173 Issue 2 Pg. 224-31 (Apr 2012) ISSN: 1095-8673 [Electronic] United States
• PMID: 21777927 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2012 Elsevier Inc. All rights reserved.

Chemical References

• Collagen Type IV
• Estrogens
• TIMP1 protein, human
• TIMP2 protein, human
• Tissue Inhibitor of Metalloproteinase-1
• Tissue Inhibitor of Metalloproteinase-2
• MMP2 protein, human
• Matrix Metalloproteinase 2
• MMP14 protein, human
• Matrix Metalloproteinase 14

Topics

• Cell Movement
• Cell Proliferation
• Cells, Cultured
• Collagen Type IV
• Estrogen Replacement Therapy
• Estrogens (metabolism)
• Female
• Humans
• Hyperplasia (enzymology, etiology)
• Matrix Metalloproteinase 14 (metabolism)
• Matrix Metalloproteinase 2 (metabolism)
• Middle Aged
• Muscle, Smooth, Vascular (enzymology)
• Postmenopause (metabolism)
• RNA Interference
• Tissue Inhibitor of Metalloproteinase-1 (metabolism)
• Tissue Inhibitor of Metalloproteinase-2 (metabolism)
• Tunica Intima (enzymology)