Dependence of cathepsin L-induced coronary endothelial dysfunction upon activation of NAD(P)H oxidase.
Cathepsin L is a cysteine protease that can generate endogenous endostatin in vascular and epithelial basement membranes and importantly participates in a variety of pathophysiological processes. The present study was designed to determine whether this cathepsin L-derived endogenous endostatin alters endothelium-dependent vasodilator responses in coronary arteries via NAD(P)H oxidase activation. In isolated and perfused small bovine coronary arteries, administration of cathepsin L (200 ng/ml) markedly attenuated endothelium-dependent vasodilator responses to bradykinin or A23187 by 56.16+/-9.58% and 68.95+/-10.32%, respectively. This inhibitory effect of cathepsin L on endothelium-dependent vasodilator responses could be significantly reversed by pre-incubation of the arteries with O(2)(-) scavenger, Tiron, or neutralizing anti-endostatin antibody. By fluorescent ELISA assay, cathepsin L dose-dependently increased endostatin production in coronary arteries. In situ high-speed dual wavelength switching fluorescent microscopic imaging showed that cathepsin L decreased bradykinin- and A23187-induced NO levels in the intact endothelium, but it had no effect on Ca(2+) response to these vasodilators. This cathepsin L-induced reduction of NO was restored by the pretreatment of an anti-endostatin antibody. Electron spin resonance (ESR) analysis demonstrated that cathepsin L increased O(2)(-) production which could be markedly attenuated by the NAD(P)H oxidase inhibitors, apocynin or anti-endostatin antibody. It is concluded that endostatin could be endogenously produced in coronary arteries when cathepsin L is increased and that this cathepsin L-derived endostatin, if excessive, may result in endothelial dysfunction through enhanced production of O(2)(-) due to NAD(P)H oxidase activation.
Zhang
Fan
F
Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, 410 N 12th, Richmond, VA 23298, USA.
Zhang
Yang
Y
Li
Pin-Lan
PL
D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / Q000494:pharmacology; D000818:Animals; D001920:Bradykinin / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D056668:Cathepsin L; D002403:Cathepsins / Q000494:pharmacology*; D002417:Cattle; D003331:Coronary Vessels / Q000187:drug effects* / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D043169:Endostatins / Q000096:biosynthesis; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology*; D004789:Enzyme Activation; D016166:Free Radical Scavengers / Q000494:pharmacology; D019255:NADPH Oxidases / Q000378:metabolism*
D043169:Endostatins; D016166:Free Radical Scavengers; D000001:Calcimycin; D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D019255:NADPH Oxidases; D002403:Cathepsins; D003546:Cysteine Endopeptidases; D056668:Cathepsin L; D001920:Bradykinin