Investigating Metalloproteinases MMP-2 and MMP-9 Mechanosensitivity to Feedback Loops Involved in the Regulation of In Vitro Angiogenesis by Endogenous Mechanical Stresses
Investigating Metalloproteinases MMP-2 and MMP-9 Mechanosensitivity to Feedback Loops Involved in the Regulation of In Vitro Angiogenesis by Endogenous Mechanical Stresses
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DOI：
10.1007/s10441-012-9147-3
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发表时间：
2012-06-01
影响因子：
1.3
通讯作者：
Tracqui, Philippe
中科院分区：
文献类型：
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作者：
Minh-Uyen Dao Thi;Trocme, Candice;Tracqui, Philippe
血管生成是一个复杂的形态发生过程，受生长因子的调节，但也受到内皮细胞（EC）牵拉应力和细胞外基质（ECM）粘弹性阻力之间的力平衡的影响。用体外血管生成测定进行的研究表明，降低ECM刚度触发血管生成开关，促进EC组织成管状索或假毛细血管。因此，EC对蛋白酶分泌的机械敏感性，特别是基质金属蛋白酶（MMPs），应该在这种转换机制中发挥关键作用。虽然大多数分析MMP的应变调节的研究使用在拉伸膜上培养的细胞，但这项工作集中在EC自组装成纤维蛋白凝胶内的毛细血管样结构期间的MMP表达，即在更接近模拟体内细胞机械微环境的条件下。MMP-2和MMP-9（两种在毛细血管形成中具有关键作用的MMP）的活性已随着EAhy 926细胞在细胞索出现期间发生的进行性伸长而被监测。我们发现，与EC索形成的初始阶段相关的酶原proMMP-2的增加。MMP-2未检出。ProMMP-9分泌减少，MMP-9水平保持在相当低的值。为了更精确地分析所观察到的EAhy 926对纤维蛋白和塑料基质的反应差异，我们提出了一个理论模型的机械调节proMMP-2激活的MMPs的2型组织抑制剂（TIMP-2）的存在下。使用缔合/解离速率实验报道的这种酶网络，该模型充分描述了协同作用的proMMP-2和TIMP-2菌株激活过程中的假毛细血管形态发生。总之，这些结果为通过细胞产生的细胞外应力和菌株进行血管生成机械调节的系统生物学方法提供了第一步。
Angiogenesis is a complex morphogenetic process regulated by growth factors, but also by the force balance between endothelial cells (EC) traction stresses and extracellular matrix (ECM) viscoelastic resistance. Studies conducted with in vitro angiogenesis assays demonstrated that decreasing ECM stiffness triggers an angiogenic switch that promotes organization of EC into tubular cords or pseudo-capillaries. Thus, mechano-sensitivity of EC with regard to proteases secretion, and notably matrix metalloproteinases (MMPs), should likely play a pivotal role in this switching mechanism. While most studies analysing strain regulation of MMPs used cell cultured on stretched membranes, this work focuses on MMP expression during self-assembly of EC into capillary-like structures within fibrin gels, i.e. on conditions that mimics more closely the in vivo cellular mechanical microenvironment. The activity of MMP-2 and MMP-9, two MMPs that have a pivotal role in capillaries formation, has been monitored in pace with the progressive elongation of EAhy926 cells that takes place during the emergence of cellular cords. We found an increase of the zymogen proMMP-2 that correlates with the initial stages of EC cords formation. However, MMP-2 was not detected. ProMMP-9 secretion decreased, with levels of MMP-9 kept at a rather low value. In order to analyse more precisely the observed differences of EAhy926 response on fibrin and plastic substrates, we proposed a theoretical model of the mechano-regulation of proMMP-2 activation in the presence of type 2 tissue inhibitor of MMPs (TIMP-2). Using association/dissociation rates experimentally reported for this enzymatic network, the model adequately describes the synergism of proMMP-2 and TIMP-2 strain activation during pseudo-capillary morphogenesis. All together, these results provide a first step toward a systems biology approach of angiogenesis mechano-regulation by cell-generated extracellular stresses and strains.