Matrix metalloproteinase-2-induced epidermal growth factor receptor transactivation impairs redox balance in vascular smooth muscle cells and facilitates vascular contraction.

Increased reactive oxygen species formation may enhance matrix metalloproteinase (MMP)-2 activity and promote cardiovascular dysfunction. We show for the first time that MMP-2 is upstream of increased formation and activates signaling mechanisms impairing redox balance. Incubation of vascular smooth muscle cells (VSMC) with recombinant MMP-2 increased duanyu1670 formation assessed with dihydroethidium (DHE) by flow cytometry. This effect was blocked by the antioxidant apocynin or by polyethylene glycol-catalase (PEG-catalase), and by MMP inhibitors (doxycycline or GM6001). Next, we showed in HEK293 cells that MMP-2 transactivates heparin-binding epidermal growth factor (HB-EGF) leading to EGF receptor (EGFR) activation and increased duanyu1670 concentrations. This effect was prevented by the EGFR kinase inhibitor Ag1478, and by phospholipase C (PLC) or protein kinase C inhibitors (A778 or chelerythrine, respectively), confirming the involvement of EGFR pathway in MMP-2-induce responses. Next, we showed that intraluminal exposure of aortas to MMP-2 increased vascular MMP-2 levels detected by immunofluorescence and gelatinolytic activity (by in situ zimography) in association with increased duanyu1670 formation. This effect was inhibited by MMP inhibitors (phenanthroline or doxycycline) and by apocynin or PEG-catalase. MMP-2 also increased aortic contractility to phenylephrine and this effect was prevented by MMP inhibitor GM6001 and by apocynin or PEG-catalase, showing again that increased duanyu1670 formation mediates functional effects of MMP-2. These results show that MMP-2 activates the EGFR and triggers downstream signaling pathways increasing duanyu1670 formation and promoting vasoconstriction. These findings may have various implications for cardiovascular diseases.

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