Inhibition of cathepsin D prevents free-radical-induced apoptosis in rat cardiomyocytes.
Apoptosis was inhibited in rat cardiomyocytes pretreated with the aspartic protease inhibitor pepstatin A and subsequently exposed to naphthazarin (5,8-dihydroxy-1,4-naphthoquinone). Cathepsin D was released from lysosomes to the cytosol upon exposure to naphthazarin, and the enzyme activity decreased simultaneously. Later, cathepsin D reappeared in granules of increased size, and enzyme activity was restored. Activation of caspase-3-like proteases was detected, and the number of cells showing apoptotic morphology increased with time. Pepstatin A pretreatment did not prevent release of cathepsin D from lysosomes but did significantly inhibit subsequent naphthazarin-induced caspase activation and apoptotic morphology. This suggests that cathepsin D exerts its apoptosis-stimulating effect upstream of caspase-3-like activation.
Ollinger
K
K
Faculty of Health Sciences, Link]oping University, Link]oping, S-581 85, Sweden. karin.ollinger@pat.liu.se
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002402:Cathepsin D / Q000037:antagonists & inhibitors*; D002478:Cells, Cultured; D004789:Enzyme Activation; D005260:Female; D005455:Fluorescent Antibody Technique; D005609:Free Radicals / Q000494:pharmacology; D006321:Heart / Q000187:drug effects; D020287:In Situ Nick-End Labeling; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D009285:Naphthoquinones / Q000494:pharmacology; D018384:Oxidative Stress; D010436:Pepstatins / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D005609:Free Radicals; D009285:Naphthoquinones; D010436:Pepstatins; C014195:Streptomyces pepsin inhibitor; C005503:naphthazarin; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; D002402:Cathepsin D; C031375:pepstatin