Fernandez-Patron C, Stewart K G, Zhang Y, Koivunen E, Radomski M W, Davidge S T
Perinatal Research Centre, Departments of Obstetrics/Gynaecology and Physiology, University of Alberta, Edmonton, Alberta, Canada.
Circ Res. 2000 Oct 13;87(8):670-6. doi: 10.1161/01.res.87.8.670.
Matrix metalloproteinase (MMP)-2 has been historically associated with the process of vascular remodeling through the cleavage of extracellular matrix proteins. However, we recently found that MMP-2 also cleaves the endothelium-derived peptide big endothelin-1, ET-1[1-38] and yields the novel vasoconstrictor ET-1[1-32]. We therefore investigated the effects of MMP-2 inhibitors as potential vasodilators. MMP inhibition with ortho-phenanthroline (0.3 to 30 micromol/L) induced vasorelaxation of isolated rat mesenteric arteries (maximum of relaxation=74.5+/-27.6% at 30 micromol/L). However, phosphoramidon (0.3 to 30 micromol/L), which inhibits some metalloenzymes, but not MMP-2, did not dilate the arteries. Selective inhibition of endogenous MMP-2 with the novel tissue-permeable cyclic peptide CTTHWGFTLC (CTT, 10 micromol/L) also caused vasorelaxation (by 85+/-6%), whereas STTHWGFTLS (10 micromol/L), an inactive CTT analogue, did not dilate the arteries. Interestingly, the vasorelaxation that results from MMP-2 inhibition was endothelium-independent. Thus, we examined whether MMP-2 acted on peptides derived from the smooth muscle or the perivascular nerves. Recombinant human MMP-2 cleaved calcitonin gene-related peptide (CGRP) specifically at the Gly(14)-Leu(15) peptide bond and reduced the vasodilatory potency of CGRP by 20-fold. Inhibition of MMP-2 increased the amount of intact CGRP in arteries and enhanced vasorelaxation induced by anandamide, which stimulates CGRP release. Vasorelaxation in response to MMP-2 inhibition was abolished by CGRP[8-37], a selective CGRP receptor antagonist, and by capsaicin, which depletes arterial perivascular nerves of CGRP. We conclude that vascular MMP-2 cleaves endogenous CGRP and promotes vasoconstriction. These data suggest a novel mechanism of regulating the vasoactive and, possibly, the neurohormonal actions of CGRP and establish MMP-2 as a modulator of vascular function.
基质金属蛋白酶（MMP）-2一直以来都与通过裂解细胞外基质蛋白进行血管重塑的过程相关。然而，我们最近发现MMP-2还能裂解内皮源性肽大内皮素-1（ET-1[1-38]），并产生新型血管收缩剂ET-1[1-32]。因此，我们研究了MMP-2抑制剂作为潜在血管舒张剂的作用。用邻菲罗啉（0.3至30微摩尔/升）抑制MMP可诱导离体大鼠肠系膜动脉血管舒张（在30微摩尔/升时最大舒张率为74.5±27.6%）。然而，抑制某些金属酶但不抑制MMP-2的磷酰胺（0.3至30微摩尔/升）并不能使动脉扩张。用新型可穿透组织的环肽CTTHWGFTLC（CTT，10微摩尔/升）选择性抑制内源性MMP-2也会导致血管舒张（达85±6%），而无活性的CTT类似物STTHWGFTLS（10微摩尔/升）则不能使动脉扩张。有趣的是，MMP-2抑制所导致的血管舒张不依赖于内皮。因此，我们研究了MMP-2是否作用于平滑肌或血管周围神经衍生的肽。重组人MMP-2特异性地在甘氨酸（14）-亮氨酸（15）肽键处裂解降钙素基因相关肽（CGRP），并使CGRP的血管舒张效力降低20倍。抑制MMP-2可增加动脉中完整CGRP的量，并增强由阿南酰胺刺激CGRP释放所诱导的血管舒张。选择性CGRP受体拮抗剂CGRP[8-37]和使动脉血管周围神经中的CGRP耗竭的辣椒素可消除对MMP-2抑制的血管舒张反应。我们得出结论，血管MMP-2可裂解内源性CGRP并促进血管收缩。这些数据提示了一种调节CGRP血管活性以及可能的神经激素作用的新机制，并确立MMP-2为血管功能的调节因子。
