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Matrix metalloproteinase (MMP)-3 activates MMP-9 mediated vascular smooth muscle cell migration and neointima
Jason L Johnson1, Amrita Dwivedi, Michelle Somerville
1Bristol Heart Institute, University of Bristol, Bristol, United Kingdom. jason.l.johnson@bristol.ac.uk
Objective:
Several matrix metalloproteinases (MMPs) have been implicated in extracellular matrix destruction and other actions that lead to plaque rupture and myocardial infarction. Conversely, other MMPs have been shown to promote vascular smooth muscle cell (VSMC)-driven neointima formation, which contributes to restenosis, fibrous cap formation, and plaque stability. MMP-3 knockout reduced VSMC accumulation in mouse atherosclerotic plaques, implicating MMP-3 in neointima formation. We therefore investigated the effect of MMP-3 knockout on neointima formation after carotid ligation in vivo and VSMC migration in vitro.
Methods And Results:
Twenty-eight days after left carotid ligation, MMP-3 knockout significantly reduced neointima formation (75%, P<0.01) compared with wild-type (WT) littermates, and also reduced remodeling of ligated and contralateral carotid arteries. Gelatin zymography illustrated that MMP-3 knockout abolished MMP-9 activation in ligated carotids and scratch-wounded VSMC cultures. MMP-3 knockout also attenuated VSMC migration into a scratch wound by 59% compared with WT cells. Addition of exogenous MMP-3 or activated MMP-9 restored migration of MMP-3 knockouts to that of WT VSMCs, but exogenous MMP-3 had no effect on migration in MMP-9 knockout VSMCs. MMP-9 knockout or knockdown with small interfering RNA significantly retarded VSMC migration to the same extent as MMP-3 knockout.
Conclusions:
These results indicate for the first time that MMP-3 mediated activation of MMP-9 is required for efficient neointima formation after carotid ligation in vivo and for VSMC migration in vitro, whereas MMP-12 plays a redundant role. These findings add to the understanding of MMP action in plaque stability and restenosis.
Insights
Matrix metalloproteinase-3 (MMP-3) knockout significantly reduced neointima formation and vascular smooth muscle cell migration by inhibiting MMP-9 activation. This highlights MMP-3
Area of Science:
- Cardiovascular Biology
- Molecular Medicine
- Atherosclerosis Research
Background:
- Matrix metalloproteinases (MMPs) play dual roles in cardiovascular disease, contributing to plaque rupture or neointima formation.
- MMP-3 has been implicated in vascular smooth muscle cell (VSMC) accumulation and neointima formation, a key process in restenosis.
- Understanding the specific roles of MMPs is crucial for developing targeted therapies for cardiovascular conditions.
Purpose of the Study:
- To investigate the role of MMP-3 knockout in neointima formation following carotid artery ligation in vivo.
- To determine the effect of MMP-3 knockout on vascular smooth muscle cell (VSMC) migration in vitro.
- To elucidate the relationship between MMP-3, MMP-9, and neointima formation/VSMC migration.
Main Methods:
- Carotid artery ligation model in wild-type (WT) and MMP-3 knockout mice.
- Quantification of neointima formation and arterial remodeling 28 days post-ligation.
- In vitro VSMC migration assays (scratch wound model) using WT, MMP-3 knockout, and MMP-9 knockout/knockdown cells.
- Gelatin zymography to assess MMP-9 activity.
Main Results:
- MMP-3 knockout significantly reduced neointima formation by 75% and arterial remodeling after carotid ligation.
- MMP-3 knockout abolished MMP-9 activation in ligated arteries and VSMC cultures.
- MMP-3 knockout attenuated VSMC migration by 59%; this effect was rescued by exogenous MMP-3 or MMP-9.
- MMP-9 knockout/knockdown similarly retarded VSMC migration, indicating MMP-9 is critical downstream of MMP-3.
Conclusions:
- MMP-3 mediated activation of MMP-9 is essential for efficient neointima formation post-carotid ligation.
- MMP-3 is required for VSMC migration in vitro, acting primarily through the activation of MMP-9.
- These findings clarify the role of MMP-3/MMP-9 in plaque stability and restenosis, suggesting therapeutic targets.
