Effects of loss of occlusal contact on the expression of matrix metalloproteinase‐2, membrane type 1‐MMP, tissue inhibitor of the MMP‐2, eruption rate, organization and resistance of collagen fibers of the rat incisor periodontal ligament

2017 ◽  
Vol 53 (1) ◽  
pp. 40-46 ◽  
Author(s):  
N. F. Omar ◽  
J. R. Gomes ◽  
J. S. Neves ◽  
P. D. Novaes
2003 ◽  
Vol 374 (3) ◽  
pp. 739-745 ◽  
Author(s):  
M. Margarida BERNARDO ◽  
Rafael FRIDMAN

The matrix metalloproteinase (MMP)-2 has a crucial role in extracellular matrix degradation associated with cancer metastasis and angiogenesis. The latent form, pro-MMP-2, is activated on the cell surface by the membrane-tethered membrane type 1 (MT1)-MMP, in a process regulated by the tissue inhibitor of metalloproteinase (TIMP)-2. A complex of active MT1-MMP and TIMP-2 binds pro-MMP-2 forming a ternary complex, which permits pro-MMP-2 activation by a TIMP-2-free neighbouring MT1-MMP. It remains unclear how MMP-2 activity in the pericellular space is regulated in the presence of TIMP-2. To address this question, the effect of TIMP-2 on MMP-2 activity in the extracellular space was investigated in live cells, and their isolated plasma membrane fractions, engineered to control the relative levels of MT1-MMP and TIMP-2 expression. We show that both free and inhibited MMP-2 is detected in the medium, and that the net MMP-2 activity correlates with the level of TIMP-2 expression. Studies to displace MT1-MMP-bound TIMP-2 in a purified system with active MMP-2 show minimal displacement of inhibitor, under the experimental conditions, due to the high affinity interaction between TIMP-2 and MT1-MMP. Thus inhibition of MMP-2 activity in the extracellular space is unlikely to result solely as a result of TIMP-2 dissociation from its complex with MT1-MMP. Consistently, immunoblot analyses of plasma membranes, and surface biotinylation experiments show that the level of surface association of TIMP-2 is independent of MT1-MMP expression. Thus low-affinity binding of TIMP-2 to sites distinct to MT1-MMP may have a role in regulating MMP-2 activity in the extracellular space generated by the ternary complex.


2019 ◽  
Vol 316 (1) ◽  
pp. C92-C103 ◽  
Author(s):  
Hojin Kang ◽  
Zhigang Hong ◽  
Ming Zhong ◽  
Jennifer Klomp ◽  
Kayla J. Bayless ◽  
...  

Angiogenesis is initiated in response to a variety of external cues, including mechanical and biochemical stimuli; however, the underlying signaling mechanisms remain unclear. Here, we investigated the proangiogenic role of the endothelial mechanosensor Piezo1. Genetic deletion and pharmacological inhibition of Piezo1 reduced endothelial sprouting and lumen formation induced by wall shear stress and proangiogenic mediator sphingosine 1-phosphate, whereas Piezo1 activation by selective Piezo1 activator Yoda1 enhanced sprouting angiogenesis. Similarly to wall shear stress, sphingosine 1-phosphate functioned by activating the Ca2+ gating function of Piezo1, which in turn signaled the activation of the matrix metalloproteinase-2 and membrane type 1 matrix metalloproteinase during sprouting angiogenesis. Studies in mice in which Piezo1 was conditionally deleted in endothelial cells demonstrated the requisite role of sphingosine 1-phosphate-dependent activation of Piezo1 in mediating angiogenesis in vivo. These results taken together suggest that both mechanical and biochemical stimuli trigger Piezo1-mediated Ca2+ influx and thereby activate matrix metalloproteinase-2 and membrane type 1 matrix metalloproteinase and synergistically facilitate sprouting angiogenesis.


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