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Perivascular cells regulate endothelial membrane type-1 matrix metalloproteinase activity
M A Lafleur1, P A Forsyth, S J Atkinson
1School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, England.
Abstract:
Angiogenic stimuli selectively induced expression of membrane type-1 matrix metalloproteinase (MT1-MMP) transcripts and protein in human umbilical vein endothelial cells (HUVECs). Pro-MMP-2 activation was blocked by treatment with tissue inhibitor of metalloproteinases-2 (TIMP-2), but not by TIMP-1 or inhibitors of other proteinase classes. Anti-MT1-MMP antibodies abrogated recombinant pro-MMP-2 activation by plasma membranes, indicating that MT1-MMP is the main mediator of pro-MMP-2 activation in HUVECs. Cocultures of HUVECs with smooth muscle cells (SMC) or pericytes (PC) resulted in the suppression of HUVEC pro-MMP-2 activation. Treatment of A10 SMC conditioned media with a neutralising anti-TIMP-2 antibody prevented the suppression of HUVEC pro-MMP-2 activation. Inhibition of HUVEC MT1-MMP function by PC and SM3 SMC correlated with elevated TIMP-3 expression. Thus, perivascular supporting cells regulate the functions of proangiogenic MMPs elaborated by endothelial cells via selective expression of TIMPs. This interplay may be important for maintenance of blood vessel architecture and neovascularisation.
Insights
Angiogenic stimuli increase membrane type-1 matrix metalloproteinase (MT1-MMP) in endothelial cells. Perivascular cells regulate this process through tissue inhibitors of metalloproteinases (TIMPs), impacting blood vessel formation.
Area of Science:
- Endothelial cell biology
- Extracellular matrix remodeling
- Angiogenesis research
Background:
- Endothelial cells initiate blood vessel formation during angiogenesis.
- Matrix metalloproteinases (MMPs) are crucial for extracellular matrix degradation in angiogenesis.
- Membrane type-1 matrix metalloproteinase (MT1-MMP) plays a key role in pro-MMP-2 activation.
Purpose of the Study:
- To investigate the role of MT1-MMP in endothelial cells during angiogenesis.
- To determine how perivascular cells influence endothelial cell MMP activity.
- To elucidate the mechanisms by which supporting cells regulate endothelial MMPs.
Main Methods:
- Culture of human umbilical vein endothelial cells (HUVECs) with angiogenic stimuli.
- Assessment of MT1-MMP expression and activity.
- Pro-MMP-2 activation assays using inhibitors and antibodies.
- Coculture experiments with smooth muscle cells (SMC) and pericytes (PC).
- Analysis of tissue inhibitor of metalloproteinases (TIMP) expression.
Main Results:
- Angiogenic stimuli upregulated MT1-MMP in HUVECs.
- MT1-MMP was identified as the primary mediator of pro-MMP-2 activation in HUVECs.
- Coculture with SMCs or PCs suppressed HUVEC pro-MMP-2 activation.
- This suppression was linked to TIMP-2 in SMC-conditioned media.
- Perivascular cells inhibited HUVEC MT1-MMP activity via TIMP-3 expression.
Conclusions:
- Perivascular cells modulate endothelial cell MT1-MMP function through selective TIMP expression.
- This regulation by supporting cells is critical for controlling MMP activity in angiogenesis.
- The interplay between endothelial cells and perivascular cells is vital for maintaining blood vessel architecture and neovascularization.