Effects of reactive metabolites of oxygen and nitrogen on gelatinase A activity

Abstract

The regulation of matrix metalloproteinase activity is crucial for maintaining the proper balance of tissue remodeling vs. injury. Metalloproteinase proenzymes are activated when the active site zinc is exposed via a cysteine switch mechanism. Peroxynitrite, the product generated from the interaction between nitric oxide and superoxide, has been shown to release zinc from zinc-thiolate groups, suggesting that it might alter metalloproteinase activity. This study examined the effects of nitric oxide and superoxide generators on gelatinase A activity. Results showed that nitric oxide alone had no effect on gelatinase A activity relative to control, whereas superoxide-derived metabolites increased activity. The simultaneous generation of both nitric oxide and superoxide caused an inhibition of gelatinase A activity. This inhibition was reversed by the addition of hemoglobin, superoxide dismutase, or sodium urate, suggesting that peroxynitrite and/or peroxynitrous acid caused the inhibition. Authentic peroxynitrite also inhibited gelatinase A activity. We postulate that the relative fluxes of nitric oxide and superoxide at sites of inflammation may modulate metalloproteinase activity and thus affect matrix protein metabolism.

Nitric oxide modulates caveolin-1 and matrix metalloproteinase-9 expression and distribution at the endothelial cell/tumor cell interface

“…To evaluate the sensitivity of MMP-9 to RNOS, we exposed purified MMP-9 to chemically generated NO or ONOO Ϫ in ranges utilized by others to study the effects of these species on MMP-2 (23). As Owens et al (23) had shown for MMP-2, we observed that ONOO Ϫ significantly decreased MMP-9 activity, with both the latent and active forms affected. In contrast to their observations, NO generated by spermineNONOate inhibited MMP-9 activities in a dose-dependent manner.…”

“…Samples were then incubated for 5 h at 37°C with either spermine-NONOate (0.5 and 1 M) or SIN-1 (20 M, 200 M, and 2 mM). The rate of NO production from spermine-NO, as determined spectrophotometrically with NO-specific electrode, was 5 or 10 nmol/min for 0.5 and 1 M, respectively (23). SIN-1 generates equimolar amounts of O 2 Ϫ and NO, which interact to form ONOO Ϫ .…”

“…SIN-1 generates equimolar amounts of O 2 Ϫ and NO, which interact to form ONOO Ϫ . Owens et al (23) reported that 100 M SIN-1 produced ϳ30 M ONOO Ϫ after a 30-min incubation time at 37°C assayed by monitoring rhodamine formation. We have previously reported that the lung cancer cell lines produce micromolar amounts of NO (27).…”

Matrix metalloproteinases in kidney homeostasis and diseases

“…The cysteine switch contains a thiol residue that can be altered by reactive oxygen species (ROS) and reactive nitrogen species (RNS), causing dissociation from the catalytic site, leading to enzyme activation (96,137). Such regulation is tightly controlled, as it is shown that at lower concentrations, MMP-7 is activated by hypochlorous acid (from myeloperoxidase), whereas at higher concentrations MMP-7 is inactivated, apparently through oxidative crosslinking of amino acids affecting the active site (31, 32).…”

Matrix Metalloproteinases in Lung: Multiple, Multifarious, and Multifaceted

“…The relative fluxes of nitric oxide and superoxide at sites of inflammation are shown to differentially modulate MMP2 activity, because superoxide-derived metabolites increase activity of MMP2 in vitro, while peroxynitrite, which is formed from the interaction between superoxide and nitric oxide, inhibits MMP2 activity (204). MMP activity may also be altered by environmental pollutants.…”